Two Stroke Motocross
Two Stroke Motocross Forum => General Two Stroke Talk => Topic started by: KXwestYZ on January 16, 2010, 09:26:21 AM
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After we had the chat about handicapped 4 strokes I decided to post on the vital mx forum about how its unfair 4 strokes have this handicap, I've always steered clear of other motocross sites cos I thought they woldnt have members who were at all interested in 2 stroke-
http://www.vitalmx.com/forums/MotoRelated,20/westyz,777553?page=1#topic_778136 (http://www.vitalmx.com/forums/MotoRelated,20/westyz,777553?page=1#topic_778136)
I posted this thread and to be honest I was really impressed that maybe 85% of the responces have been supportive and constructive about the plight of 2 strokes...
Not sure if its same on other sites but thought I'd share this as a positive experience I had. Maybe things are changing out there..
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I was surprised you weren't shot on site. :o I had posted this a couple days prior. http://www.vitalmx.com/forums/MotoRelated,20/Joke-Bad-golfers-and-4-stroke-riders-have-something-in-common,776544 (http://www.vitalmx.com/forums/MotoRelated,20/Joke-Bad-golfers-and-4-stroke-riders-have-something-in-common,776544) I think the 4 stroke guys are getting worn down. :P
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well done.But what the 4t people need to understand is swept volume a 2t dose not have the power stroke of a 4t.Although a 4t fires on the 4th stroke that stroke is twice as much as a 2t, because of the the ports on a 2t are open half way down the bore.This is an advantage that the 4ts have as well as twice the displacement and must be used in any argument of 4t =2t 4t people never think of that.
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All i can say is WOW! These guys are definitely interesting in the way they talk, and the way they view things. One guy said that he had owned a 2 stroke, but had no where near the talent to ride it, he said that his four stroke covered that up. Four strokes are KILLING talent and good form.
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You're a brave man for posting on that site....
Thanks for mentioning the site and acting with dignity and intelligence. I truly believe that by stating the facts as we see them instead of telling folks they are dumb or stupid for their choice to race four-strokes will be the way to bring back the two-strokes.
I'm actually surprised they were so nice to you!! Guy B is the owner of Vital and he commented and even asked a question... usually he just says something brief and not so nice about two-strokes... but then he makes a bunch of money working or the Big 4 manufacturers...
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KXwestYZ excellent post, well stated, your expressed you opinion and let others comment without being argumentive.
In my opinion, the racing would be so much better if it was both strokers and smokers. I believe that both bikes will handle the track obstacles differently. For example, (In my opinion) I see the strokers as a bike that prefers to rails turns, and the smoker as one that square up turns more, is easier to change lines, while the torque of the stroker will allow it to get out of a corner to set up for an obstacle differently then the way the smoker puts the power to the ground. This (again in my opinion) shows there will be more areas on the track where the bikes would react differently. I see more passing, closer racing, more exciting for us, the MX fan.
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Interesting replies. I especially liked the one who said the whole "handicap" concept made him look at 4 strokes differently now. If just ONE announcer at a Supercross race would mention that, if just ONE mx magazine could use that angle when reviewing a 4 stroke, it would start seeping into the consciousness of prospective 4 stroke buyers. I know i sure as hell wouldn't want to ride a bike that needed a "handicap"
If you want to look at the displacement disparity in yet another way, think about if AMA rules forced 125cc 4 strokes against 250cc 2 strokes. Think about that for a moment, it's absolutely laughable right? Unthinkable right? Yet it's perfectly ok the other way around. Just goes to show what a superior engine the 2 stroke is.
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Man, that handicap would lead to a total slaughter, wouldn't it? The guys on 125 4Ts would be down ten seconds a lap!
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Jetzcorp, that's funny!! It amazing that the four-stroke supporters see their handicap as being straight up racing. They would all cry if it were reversed!!!
Sure the bike (four-stroke) is easy to ride because of a tame power delivery, but it's as slow as a stone! Especially when it's half the size of a two-stroke. ;D ;D ;D
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Here's the question I posed for my good friend who argues with me about 2 and 4 strokes weekly. I have always said, if the 4 stroke wouldn't have had handicaps, the 4 strokes would have never taken off like they did and the 2 strokes wouldn't have died. He said yes they would have bla bla bla. Same ol same ol about demand etc. So this weekend while arguing I said, Ok, let's take a look at what you say and I say. If it would have been 125 4 stroke and 250 4 stroke from the beginning, and no 450F, would it still be 4 stroke rules. He paused and said, well, and really couldn't answer well. I said it would be about 50/50 in my opinion, and he somewhat agreed. He did mention the manufactures were pushing the 4 strokes with advertisement etc. But I opened his mind up with that question. Sure when compared to the 2 strokes the 450f is the key to their arguments. But when you take that bike out completely, then you get a ....?
The reason I say 50% each is as follows. First, the 4 stroke is better for beginners. The 4 stroke is better for women. The 4 stroke is better for some, in how they race. But on shear power and the better bike, the others would sell. So again, my opinion is 50/50 or somewhere close.
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You have hit upon the root of the entire problem... the only reason there are four-strokes in motocross is because of the handi-cap allowing them almost double displacement.
Any one that argues that the four-strokes would have taken off if they were equal displacement is sadly mistaken, it would never have happened at all.
Now that we are at this point, the four-stroke supporter argument has changed, as it has over the course of it's rein. Now they are saying that no one liked two-strokes, they were this, they were that... all conveniently avoiding the one and only reason... bigger displacement!!
I truly see this as the largest swindle in motocross history. A total shame!
The only way to get these folks to see the "light" is to be respectful to them, they are just confused and convinced their opinion is correct. Yelling at them and calling them names will have a tremendously detrimental effect and not help our cause one iota.
Which has been so brilliantly demonstrated by KXwestYZ in his initial post on Vital and in his follow up responses. Amazing and wonderful results can be achieved by following his example. Thanks again!
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Guy B is the owner of Vital and he commented and even asked a question... usually he just says something brief and not so nice about two-strokes... but then he makes a bunch of money working or the Big 4 manufacturers...
John, since RupX pointed out TSM on Vital today, I figured it'd be worth stopping by to clear up a couple things that I noticed.
1. You're mistaken. I don't own Vital MX. I'm an employee here.
2. As far as me making a bunch of money working "or" the Big 4...I also happened to notice in another thread that someone commented that Yamaha was an advertiser on Vital. The last time I checked, they were still interested in selling two-strokes, too. Yes, they advertise. But that doesn't dictate opinion. The same goes for the other manufacturers.
3. Yes, I occasionally have fun with some of the two-stroke aficionados over on Vital. But that's generally when they bring up the notion that there's some kind of secret society where I'm supposed to talk up four-strokes, and talk down two-strokes. Or that I'm getting paid off. To clarify for the crew here, I grew up watching and riding two-strokes. I get that they're fun to ride, cheaper to maintain, etc. Yes, I still love the smell and sound of a two-stroke, etc.
4. I did notice one other thread where there was a quote from me in Racer X. "I think two-strokes are sort of like a past relationship. You remember the good parts, and quickly forget the bad parts. There's a lot of nostalgia for the scent, and the sound, but the equipment and racing itself is better now." I don't remember the exact context of the thread that came from, but it's a personal opinion, and I'll give you an example of what I'm talking about from last summer.
During the intermission race at Unadilla during last year's National that featured both vintage and modern two-strokes, I was watching the riders drop into the Screw-U section, and back out. I also watched the pro class guys through there during one of their motos. Where a lot of the two-stroke guys were having trouble keeping the front end down, and were busy fanning the clutch, while almost universally, the four-stroke guys were motoring smoothly up the hill. There's a lot less flailing on the four-strokes. That's part of what prompted my comment.
Anyway, that's it for my quick stop by here. Have fun, and watch out for the black helicoptors. ;)
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I got to agree that there is a conspiracy theory theme to alot of 2 stroke fans posts.
I just like riding them, and I would love to see some at the pro races.
And i hope to see some manufacturers continue to develop new technologies to fully use the 2 stroke potential. Because I plan on continuing to purchase new bikes.
I think we can all agree on this.
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I'll second it.
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That is a funny ass quote though
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Guy B is the owner of Vital and he commented and even asked a question... usually he just says something brief and not so nice about two-strokes... but then he makes a bunch of money working or the Big 4 manufacturers...
John, since RupX pointed out TSM on Vital today, I figured it'd be worth stopping by to clear up a couple things that I noticed.
1. You're mistaken. I don't own Vital MX. I'm an employee here.
2. As far as me making a bunch of money working "or" the Big 4...I also happened to notice in another thread that someone commented that Yamaha was an advertiser on Vital. The last time I checked, they were still interested in selling two-strokes, too. Yes, they advertise. But that doesn't dictate opinion. The same goes for the other manufacturers.
3. Yes, I occasionally have fun with some of the two-stroke aficionados over on Vital. But that's generally when they bring up the notion that there's some kind of secret society where I'm supposed to talk up four-strokes, and talk down two-strokes. Or that I'm getting paid off. To clarify for the crew here, I grew up watching and riding two-strokes. I get that they're fun to ride, cheaper to maintain, etc. Yes, I still love the smell and sound of a two-stroke, etc.
4. I did notice one other thread where there was a quote from me in Racer X. "I think two-strokes are sort of like a past relationship. You remember the good parts, and quickly forget the bad parts. There's a lot of nostalgia for the scent, and the sound, but the equipment and racing itself is better now." I don't remember the exact context of the thread that came from, but it's a personal opinion, and I'll give you an example of what I'm talking about from last summer.
During the intermission race at Unadilla during last year's National that featured both vintage and modern two-strokes, I was watching the riders drop into the Screw-U section, and back out. I also watched the pro class guys through there during one of their motos. Where a lot of the two-stroke guys were having trouble keeping the front end down, and were busy fanning the clutch, while almost universally, the four-stroke guys were motoring smoothly up the hill. There's a lot less flailing on the four-strokes. That's part of what prompted my comment.
Anyway, that's it for my quick stop by here. Have fun, and watch out for the black helicoptors. ;)
Thank you for stopping by and clearing up some false information. I appreciate it.
Probably best to respond to your notes by number...
1. Sorry, here I assumed something that was totally wrong. In my defense, every time I've heard anything about Vital is was in the same sentence with your name. Who does own Vital??
2. This was not my full understanding.. I've mentioned it in other areas of the site before, when any media outlet sells advertising, it is difficult to say lots of bad things about them. Not a conspiracy, just smart business. Yes I have seen Yamaha advertisements on Vital, but the ones I did see were about the bikes they were trying to sell (I believe leftover four-strokes)
Also if memory serves correctly, you have done freelance photography for Yamaha. I know that when someone pays me for a job, I consider myself an employee of that company...
Yes, I mis-spelled "for" but you mis-spelled helicopter! ;D ;D
3. Secret society? How can we join?? :P
4. I thought it was an interesting quote and worth repeating... believe it or not, I did get it.
The Unadilla race was a hoot!! Yes the two-strokes do require a bit more work to get around the track... we all agree to that. My question is what would happen at that same point were the 250 two-strokes and 250 four-strokes allowed to race each other... you know the joke about equal displacement??
If you read this entire thread you will notice that I suggest that members of this site (and others) be respectful of others...
As one last parting comment, why is it because some people don't agree with you about four-strokes that they are labeled crazy or nostalgic or conspiracy theorists??
Black helicopters?? Really??
Personally I would have wanted to be a fly on the wall at the AMA meeting late last year, early this year where it was decided that 250 vs 250 wasn't fair.
It would also be interesting to ask or find out why the FIM changed from 250 vs 250 for 2010..
All the two-stroke "fanatics" have been asking for, is fair rules. The current handicap does not work and is not fair.
As for responses on the forums, some folks get carried away and say silly and sometimes stupid things. It's the nature of an open forum and it goes both ways....
All the best..
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Vital MX is a part of the Vital Media Network... here is a link to their "About Us" page...
http://www.vitalmedianet.com/?page_id=2 (http://www.vitalmedianet.com/?page_id=2)
As I stated previously, I stand corrected.
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For those interested in the post on Vital MX that prompted Guy B to stop by and visit, here you go...
http://www.vitalmx.com/forums/MotoRelated,20/The-2-Stroke-Backlash,927236 (http://www.vitalmx.com/forums/MotoRelated,20/The-2-Stroke-Backlash,927236)
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I checked Vital MX out and noticed quite a few 2-stroke haters or at least un-beleivers on the site,one blogger said "2-strokes are dead,get over it".I say in my book 2-strokes are ALIVE & WELL!!!and if a day comes where the companies quit making the 2-strokes or the government outlaws the 2-stroke for whatever sick reason I'll just buy used 2-strokes & rebuild them as needed!I personally will always own & ride 2-stroke dirtbikes until I either DIE or become so CRIPPLED that I can't ride any longer!!!!GOD BLEES THE 2-STROKES LEFT OUT THERE! :)
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Vital Mx.......everything u don't want your forum to be :-X
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I do believe too much time is spent bitching about the 4 stroke bikes. In '72 when the displacement rule was instituted they needed the advantage and the manufacturers took advantage of it starting in '99. Ironically it started with Yamaha,the only big 4 manufacturer still selling 2 strokes in the USA. We should just ride our bikes and eventually tables will turn. It's beginning already.
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There is only bitching about 4 strokes because they have to "cheat" and are too expensive to maintain. ::)
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And i hope to see some manufacturers continue to develop new technologies to fully use the 2 stroke potential.
While it's nice to have improvements, eventually you would get a two stroke that is just as fragile as the current four strokes. I mean that's what they do to four strokes, they try to build them to their full potential, and as a result they are very unreliable. You can't have power and reliability at the same time.
A two stroke could also be made much more powerful and at the same time more fragile by using lighter parts, less material etc... I hope I'm wrong, because I like how reliable they are right now compared to four strokes. Now we at least have a choice, but what if two strokes go the same way as four strokes did? To be competitive you would have to get the new bikes, and you would end up with a flimsy piece of metal no matter if you buy the 4st or the 2st :(. Does this make any sense at all :D ? I hope I'm wrong :).
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You do already have that they are GP 125 road race bikes, the Aprilia RSW125 and the discontinued KTM FRR125 both make in the vicinity of 55HP on the wheel. The Aprilia/KTM 250's (09 was the last year of 250GP :'( ) make over 110HP at the wheel. Unreliable, well most survive a weekend at 14,000rpm that's all that matters. Parts are expensive and light but who wouldn't want a 110HP 100kg bike?
http://www.sportrider.com/features/146_1004_marco_simoncelli_gilera_rsa250/index.html (http://www.sportrider.com/features/146_1004_marco_simoncelli_gilera_rsa250/index.html)
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That's crazy but I wouldn't want one if I can't afford to maintain it. :(
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Well the same was probably said in the 80s when they switched to water cooling and power valves.
If they would have stopped there then we would be riding around like Jetz.
Bring on DFI!!!
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And i hope to see some manufacturers continue to develop new technologies to fully use the 2 stroke potential.
While it's nice to have improvements, eventually you would get a two stroke that is just as fragile as the current four strokes. I mean that's what they do to four strokes, they try to build them to their full potential, and as a result they are very unreliable. You can't have power and reliability at the same time.
A two stroke could also be made much more powerful and at the same time more fragile by using lighter parts, less material etc... I hope I'm wrong, because I like how reliable they are right now compared to four strokes. Now we at least have a choice, but what if two strokes go the same way as four strokes did? To be competitive you would have to get the new bikes, and you would end up with a flimsy piece of metal no matter if you buy the 4st or the 2st :(. Does this make any sense at all :D ? I hope I'm wrong :).
According to Mitch Payton you are wrong. He said we had already maxed out the 2 strokes. That's the thing about a 2 stroke motor. You can port them, and you can put a pipe, and a intake on them for about $600? On a 250F, you can spend that on just a pipe. The whole reason 4 strokes have amost equal power, is because they run at about double rpm to make up for the lack of firing at the other 2 strokes, and that is with double the displacement as well. A 2 stroke is harder to turn up the rpm's like that because of the back pressure etc. I don't believe most 2 strokes even have a rev limiter because of that. It just runs out before it could explode.
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Vital Mx.......everything u don't want your forum to be :-X
I agree...
It's so nice to have conversations with like minded folks that respect each other... I truly appreciate everyone on this board for following that one rule.
You guy's are the best!
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I do believe too much time is spent bitching about the 4 stroke bikes. In '72 when the displacement rule was instituted they needed the advantage and the manufacturers took advantage of it starting in '99. Ironically it started with Yamaha,the only big 4 manufacturer still selling 2 strokes in the USA. We should just ride our bikes and eventually tables will turn. It's beginning already.
Hi Big Boar...
Are you sure that the displacement rule was instituted in 1972?? If so, do you have any sources for this information? I've been trying to hunt it down for quite some time. Thanks!
As for the complaints about the four-strokes, much of that is from people that have been burned by it.. sometimes folks just want to let a little steam off. I agree with you, the best way to handle the situation is to chose the bike you prefer and enjoy riding/racing it.
As for the tables turning now, some of it's due to people speaking out about it. In some cases giving others the "words" they need to settle the confusion in their own mind.
It's a difficult road to take, when everyone around you is saying that you are wrong, to step out and think on your own.
My hope is that this site contributes in some small way to making it easier for people to decide on their own.
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According to Mitch Payton you are wrong. He said we had already maxed out the 2 strokes.
If so than it's great. Gives me a feeling of security :D.
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I'll second it.
So you do know what a ratio-rite is for then :D
Nice to see you here!
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Well the factories are handing you a race ready bike that with little modification can be competitive on a national scale-if you are. It's pointless and adolescent to trade insults and barbs. Before you toss one my way I own both. But the CRF is up waiting for me to gather cash for a rebuild. After which it's probably going up for sale so I can buy a modern (300 KTM) big bore smoker. Yep I drank the Kool Aid. Meanwhile I ride my '80 YZ465. Great bike,only 2nd over after 31 years. Well it did spend about 15 years in the corner of the original owners garage after he broke a femur after 3 rides. 2nd owner only rode it 3 or 4 times then sold it to my ex for a Xmas present for me. Man I miss her. :D
John it was 1972 as far as I can remember and this is the only documentation I can find-from The American Motorcyclist June '97. Maybe a year or so in either direction but I am reasonably certain it was '72.
(http://img.photobucket.com/albums/v606/TRexRacing/4stroke.jpg)
And a Ratio -Rite is for people that suck at math. :D
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(http://img.photobucket.com/albums/v606/TRexRacing/4stroke.jpg)
And a Ratio -Rite is for people that suck at math. :D
That is very interesting. So the original 360cc vs 250cc would have actually worked. Go figure.
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Oh and I'd like to call your attention to something fun and interesting. You can race 500CC 2 strokes in the Vet/Senior classes. Hell the rules are written so if you toss some knobbies on a Sportster you can run it. Us old guys can have all the fun. Big Bore Smokers Rule.
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That is very interesting. So the original 360cc vs 250cc would have actually worked. Go figure.
Probably not. These were heavy, slow revving, 4 strokes that would have had a devil of a time being muscled around the track. Doug Henry not withstanding, I don't believe the 4 strokes were finally competitive until the 450F's came around. Even the YZ400F and YZ426 were brutes that would wear the rider out and had trouble competing with the smokers. It took a full 200cc handicap and years of technological advancement before they could beat the 2 strokes straight up
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That is very interesting. So the original 360cc vs 250cc would have actually worked. Go figure.
Probably not. These were heavy, slow revving, 4 strokes that would have had a devil of a time being muscled around the track. Doug Henry not withstanding, I don't believe the 4 strokes were finally competitive until the 450F's came around. Even the YZ400F and YZ426 were brutes that would wear the rider out and had trouble competing with the smokers. It took a full 200cc handicap and years of technological advancement before they could beat the 2 strokes straight up
That's what I meant. That given what we know now. That if the rule that was on the books from the 70's until 1994, in 2010 would probably be perfect today. It was only a 4 year span from when they upped the rules to 550 to Doug Henry. So for a 4 year rule, it messed up a 30 year rule. If they would have made the rule back to original in 1999 when Doug Henry won on the 400f, today we would have about 50/50 of 2 and 4 strokes out there. I still can't figure out the logic in the room when they shot out the cc rule after Doug won. Ok, guys, Doug Henry just won on a 400F, and we all know the bike is gonna only get better. So let's make it 450cc...
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It's pointless and adolescent to trade insults and barbs. Before you toss one my way I own both.
You and I are in complete agreement here. Personally I feel that the barbs and insults have created more problems than the bikes ever did.
As for tossing you one, it won't happen from me! 8) 8)
Thank you so much for posting the blurb from the AMA magazine.... I must have missed that issue.
By the way nice YZ you have there... not sure if you saw the one I restored, it's worth a look... ;D ;D
http://projectyz.jfn3.com/ (http://projectyz.jfn3.com/)
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I still can't figure out the logic in the room when they shot out the cc rule after Doug won. Ok, guys, Doug Henry just won on a 400F, and we all know the bike is gonna only get better. So let's make it 450cc...
Then to add insult to injury, they passed the unleaded fuel rule, which lowered the available horsepower of the two-strokes...
It sort of sounds like there was an agenda of some type in place. :o :o :o ;D ;D
Oh no... here they come!!
(http://www.fivedoves.com/letters/jan2009/bc6bf6.jpg)
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That is very interesting. So the original 360cc vs 250cc would have actually worked. Go figure.
Probably not. These were heavy, slow revving, 4 strokes that would have had a devil of a time being muscled around the track. Doug Henry not withstanding, I don't believe the 4 strokes were finally competitive until the 450F's came around. Even the YZ400F and YZ426 were brutes that would wear the rider out and had trouble competing with the smokers. It took a full 200cc handicap and years of technological advancement before they could beat the 2 strokes straight up
That's what I meant. That given what we know now. That if the rule that was on the books from the 70's until 1994, in 2010 would probably be perfect today. It was only a 4 year span from when they upped the rules to 550 to Doug Henry. So for a 4 year rule, it messed up a 30 year rule. If they would have made the rule back to original in 1999 when Doug Henry won on the 400f, today we would have about 50/50 of 2 and 4 strokes out there. I still can't figure out the logic in the room when they shot out the cc rule after Doug won. Ok, guys, Doug Henry just won on a 400F, and we all know the bike is gonna only get better. So let's make it 450cc...
Gotcha, i see what you meant! i can't help but wonder that if all manufacturers had never stopped developing 2 strokes mx engines, if they had thrown as much development dollars at them as the 4 strokes, whether even a 450F would be able to hang with a 250 2 stroke. I mean KTM is the only one of the very big manufacturer's to continue. If the whole world was still developing them (not just for snowmobiles) i have a feeling we'd see some incredible advances.
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Totally agree. The 2 strokes would have different fueling most likely, which would cut down on some of the fouling or seizing of the motors. The bikes would be faster. KTM's is at 51 hp. I think in 2005, they didn't even fathem that, and said they had peaked. So I agree. But from what I was told, the main reason you didn't see any more 2 strokes on Honda's floor wasn't because of lack of sales etc. It was because they felt it was truely pulling sales away from the 4 strokes. The 2 strokes were cheaper, thus some people went for cost over anything else.
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Don't worry about the black choppers I got the Barrett trained on them. Head shots only Braaaraap!
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2-Strokes & .50 Cals, my 2 favorite things!! Well, next to ..... (Family site, I think you know what I mean, ha ha!)
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Hi Big Boar, welcome to the site.
I wasn't throwing insult's, I just saw that you were new to this site and thought you may have got lost :D
I posted the IT v TT vid the other day ( you need to check all the boards Turquine ) :).
I have the same TT and know what its like to try and hang on to it :(
I am trying to swap it for a pre 85 125 but no takers at the mo.
Nice bike you have there.
Pity your not closer or we could jack up a race together.
I don't mind coming second. :P
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Thanks for the welcome. I wasn't speaking about or to anyone in particular just an observation about how these things get sometimes.
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You do already have that they are GP 125 road race bikes, the Aprilia RSW125 and the discontinued KTM FRR125 both make in the vicinity of 55HP on the wheel. The Aprilia/KTM 250's (09 was the last year of 250GP :'( ) make over 110HP at the wheel. Unreliable, well most survive a weekend at 14,000rpm that's all that matters. Parts are expensive and light but who wouldn't want a 110HP 100kg bike?
http://www.sportrider.com/features/146_1004_marco_simoncelli_gilera_rsa250/index.html (http://www.sportrider.com/features/146_1004_marco_simoncelli_gilera_rsa250/index.html)
Wow!!! Carbys on the gp bike :o :o Who woulda thought........
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Hey Big Boar.
I know what you mean.
Most of the guys here are pretty good when it comes to keeping it polite.
A bit of ribbing here and there but no insults normally.
Oh i feel a love in happening :P
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A 2 stroke is harder to turn up the rpm's like that because of the back pressure etc. I don't believe most 2 strokes even have a rev limiter because of that. It just runs out before it could explode.
I thought the rpm difference was due to the fact that 4 strokes bore x stroke have grown hugely oversquare, while 2 strokes have remained fairly square, not needing high rpm to find their horsepower? Interestingly, evinrude direct-injection 2 strokes are some of the most highly oversquare 2 strokes i've seen
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A 2 stroke is harder to turn up the rpm's like that because of the back pressure etc. I don't believe most 2 strokes even have a rev limiter because of that. It just runs out before it could explode.
I thought the rpm difference was due to the fact that 4 strokes bore x stroke have grown hugely oversquare, while 2 strokes have remained fairly square, not needing high rpm to find their horsepower? Interestingly, evinrude direct-injection 2 strokes are some of the most highly oversquare 2 strokes i've seen
I'd say you are pretty accurate, but along with what I said. :-) Meaning, when we put in the 144cc kits and 300cc kits in our 2 strokes, it is bringing the cc's up and not really losing any RPM's from it, and it would be considered overly square. But, even at being square, 4 strokes need a rev limiter like on old XRs, because they will go until they blow. The pistons will probably hold up even higher, but the valve train give's way. Where as the 2 stroke is somewhat limited via, porting and pipe. If we were to change the pipe for instance, most likely we could bring the RPM's higher, and along with that, raise the ports. But then you lose the low end. I'm theorizing that we could actually have a pipe that had a cavity that could change with RPM, somewhat like a power valve does. Maybe work together. I think we have not seen what a 2 stroke can really do yet.
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I'll add a correction to myself from what I said. 2 strokes look to be more undersquared. CR250 for instance is 66.4 x 72. So when we go to the 144cc or 300cc we are probably making them even more square. i will admit I haven't studied that side of it enough. But me being a porter, I can say I can raise RPM on a 2 stroke with changes to the ports etc.
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Well, I'll just say this about revving two-strokes. My 250 Husky, obviously, doesn't have a rev limiter, and I feel confident that if I wanted to, I could make that thing grenade by revving it. When I'm at Vmax on that bike, I'm holding it at something like 1/16 throttle, and you can tell just by listening to the engine that it does not want to go any higher. What's scary is that when you get to the point that you think, "Shit, better not go any higher!" the bike is still pulling pretty hard. I think it might have something to do with my pipe not having anything in the silencer, perhaps, because it seems as though the power curve keeps climbing to infinity. I could just be reading my bike wrong, I mean, I've never taken a Husky (or any bike) so high that it actually blows, and I don't have a tach or anything to look at a red-line, but that's just my experience. If I was feeling suicidal, I'm pretty sure I could just hold that thing wide open, break the sound barrier, leave a trail of flames, travel back in time, and shatter that motor. I don't, however, think I could just open it up and get a boom on command, I think it would take some time.
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If you want to see a two-stroke that revs to the moon... check out the little motors they put into remote control airplanes!
They rev over 20,000 rpm... without rings!
JETZcorp, you're Husky, while a cool bike will not rev as far as you think it might. My feeling is that the open silencer probably makes it sound as though it's going to blow... seriously you may want to fix that, your bike will run better.
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I think you're over-estimating how much that changes how the thing sounds. The noise it makes is exactly the same, just with higher volume and a sharper crackle on idle. As you may know, I rode it around quite a lot on the last ride without anything it it at all, just the silencer can acting like a big Tuba horn. It was much louder, but it didn't make me feel like I was going faster or revving higher. You learn to ignore it after 30 seconds and ride normally. When I rode my dad's 390, which has full packing and a spark-arrestor, it had exactly the same sort sound as the 250. Incidentally, they both have a very different sound from all the other bikes of the time. They actually sounded unique back then, OMG. And of course, I have no delusions that these bikes are made to rev as high as a modern bike, if for no other reason than because I think my rod (so to speak) is still made of 1982 metallurgy.
Anyway, a lot of what determines maximum RPM is the stroke, as I was reading in the Two Stroke Tuner's Handbook. Rods and pistons and such are limited in the amount of force you can put in them before they go, and of course we know that force goes up with speed. That means that the faster your piston gets a moving, the lower its max RPM will be for a given strength of construction. That's why the model airplane motors can rev so high, they may go from BDC to TDC in a very short time, but because the stroke is so short, they can take it because the physical speed of the parts never gets all that high. This is why four-strokes are so oversquare, so they can rev high and match the two-strokes. I think the two-strokes tend toward square (or even undersquare) because port timing is very important and you don't want 1/100th of a millimeter error in your port translating into 25 degrees of crankshaft rotation. That's my theory on that, anyway.
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I think you're over-estimating how much that changes how the thing sounds. The noise it makes is exactly the same, just with higher volume and a sharper crackle on idle.
For a really smart guy this is not such a smart statement.
How much experience do you have outside of your vintage machines? How many years have you ridden bikes of many differing decades? How many years of race tuning experience do you have?
You seem to forget that I have been around and ridden literally hundreds of different motorcycles. Including Maicos (AW 400 & 490) Husqvarna (CR390 ) air-cooled machines, watercooled machines, drum brake machines, disc brake machines, no brake machines... well you get the idea...
I understand that you love your bike, we all love our bikes, and if we don't we sell them or buy another one that we do like.
Not trying to give you a hard time but most of your knowledge and experience comes from talking to folks that have a lot of experience or from reading... there is something to be said for actual time on multiple machines.
In no way am I claiming that I know all, in fact the more I learn, the more I find out there is to learn (thank you 2T institute for that amazing quote) To me what's amaing is that over the past three months I've learned more about two-stroke tuning that I have in the previous 30 years...
All I'm asking is to keep your mind open to some new ideas, there's still lots to learn!
An open silence is irresponsible, even if there is no one within a 100 miles of you. It also makes LESS power... guaranteed!
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Open silencers cost ponies. No way around that.
And stroke is a factor in RPM limits but unless the pipe will go there you can be as oversquare as physically possible and it means nothing. Making power is like conducting an orchestra. Everything must work in concert to get the max out of the music. 2 stroke,4 stroke,rotary or steam it's all the same.
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I was just talking about the psychological effect of the sound. John has said quite a number of times that he thinks the sound of a loud bike, like one with an open silencer or straight stinger, makes the rider feel like he's going fast, or like the bike is revving higher than it really is. Well I'm saying, from my personal experience having had the bike TRIPLE in volume over the course of half a second (when the silencer fell apart) that it didn't change my perception of anything. I didn't feel like it was suddenly powerful, it didn't seem like it was revving real high. It was just louder, and then I got used to it, and kept riding. Where in the hell does tuning experience and riding a large variety of bikes come into that? I didn't say anything about horsepower, or resonance, or back-pressure, or any of that other stuff that's associated with altering a silencer. I don't contest any of that. I was just rebutting your speculation about how noise of the bike may have changed my perception of what my bike is doing.
Why does it seem like every time I write something today, people are reading something else?
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I was just talking about the psychological effect of the sound. John has said quite a number of times that he thinks the sound of a loud bike, like one with an open silencer or straight stinger, makes the rider feel like he's going fast, or like the bike is revving higher than it really is. Well I'm saying, from my personal experience having had the bike TRIPLE in volume over the course of half a second (when the silencer fell apart) that it didn't change my perception of anything. I didn't feel like it was suddenly powerful, it didn't seem like it was revving real high. It was just louder, and then I got used to it, and kept riding. Where in the hell does tuning experience and riding a large variety of bikes come into that? I didn't say anything about horsepower, or resonance, or back-pressure, or any of that other stuff that's associated with altering a silencer. I don't contest any of that. I was just rebutting your speculation about how noise of the bike may have changed my perception of what my bike is doing.
Why does it seem like every time I write something today, people are reading something else?
Hey really, I'm not trying to pick on you... please re-read some of what you wrote. It sounded like you were contesting that...
As someone that cares deeply about the longevity of our sport, I don't like to see people do things that could jeopardize our collective rights to be able to ride. When you talk about the lack of silencers on your machines, you seem to do so with a great deal of pride. At least that's how I'm reading it.
If you didn't bring it up so much, it wouldn't be an issue...
I don't want younger guys that read this board to think that kind of stuff is what they should be doing too.
Just to kind of clear things up, I'm very glad that you are a part of this community and share your ideas and opinions. It certainly makes me think about my beliefs and understandings in a new way. Your passion for two-strokes is contagious!!
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There is a formula that you can use to determine the limit factor on the RPM a motor will turn. Engineers use it when designing engines. Short stroke engines will outrev long stroke engines with similar porting layouts. Remember the Can-Am's? They had a 57mm stroke when most 250's had 64mm stroke and Maico's 250 had 70mm stroke. Now, most 250 2S have 70+mm strokes. The old Can-Am Rotax motor can be designed to out rev any of the new design motors, but it will only be an advantage in certain types of riding, like road racing.
Long stroke engines are generally more tractable and user friendly for MX. The later model 4S 50mm stroke ( + or -) allows them to get the RPM's needed to compete with a 2 stroke, and with only firing every other stroke, the motor gets that long stroke feel.
I patterned my nitro/methanol pro hillclimber after the model airplane motors. 20,000RPM is only part of the story. The HP these little motors make per cc is incredible.
Keep your mufflers packed and like new or face what we have faced up here in my area: tracks shut down from too much noise after this 4 stroke revolution.
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The ceiling for a durable engine is 5K FPM average. Depending on stroke/rod length that can mean acceleration rates over 8K FPM. The formula for average piston speed is (stroke (in MM) X 2 X RPM) / (24.2X12). Peak speed is somewhat more complex. I use software now so I can not recall the formula. Well that and I'm old too. Using that formula and a 70 MM stroke you're just a tick over 10K for 5000 FPM.
The short stroke 4 strokes achieve high rpm because the bore is large enough to have the valve area to breathe well at those speeds. The short stroke is necessitated more to allow a large bore for valve area than RPM. High RPM is the area in which VE is optimum for them.
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Current 4 stroke "The ceiling for a durable engine" don't go together. LOL
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The current crop of four stroke MX bikes is far exceeding the tune of the 2 strokes. Tune your CR250 to the level of a CRF450R and it will need frequent maintenance as well. The advantage of two strokes is the superior output at a relatively mild state of tune that the diesels simply can't match. That and the relative simplicity inherent in their design.
A CRF at 10K is at 4490 FPM. CR250 at the same is 5206. Wouldn't live long there.
Look I disagree with the current rules too. But the 4 strokes have elevated the state of the art for smokers as well. Try looking at the bright side once in a while.
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The current crop of four stroke MX bikes is far exceeding the tune of the 2 strokes. Tune your CR250 to the level of a CRF450R and it will need frequent maintenance as well. The advantage of two strokes is the superior output at a relatively mild state of tune that the diesels simply can't match. That and the relative simplicity inherent in their design.
A CRF at 10K is at 4490 FPM. CR250 at the same is 5206. Wouldn't live long there.
Look I disagree with the current rules too. But the 4 strokes have elevated the state of the art for smokers as well. Try looking at the bright side once in a while.
Huh? I don't understand your statement. What part has the 4 strokes elevated the state of the art for 2 strokes? Where would the 2 strokes be if all the same R&D went that direction? Millions upon millions have been spent on the 4 strokes. again, you are comparing apples to oranges. Please redo your calculations using 250cc vs 250cc and 450cc vs 450cc. The fact that cc's or FPM has to be higher to even compare to 2 strokes is the problem. so sure, if we up our 2 strokes 40% RPM, we will have problems. But we don't have to, the power exceeds the 4 stroke per cc without needing too. I mean, in your logic my CR500 should be compared to a Chevrolet V8.
A better deal would be to limit the 4 stroke max RPM and make them reliable.
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Huh? I don't understand your statement. (You can say that again.) What part has the 4 strokes elevated the state of the art for 2 strokes? Where would the 2 strokes be if all the same R&D went that direction? Millions upon millions have been spent on the 4 strokes. again, you are comparing apples to oranges. Please redo your calculations using 250cc vs 250cc and 450cc vs 450cc. The fact that cc's or FPM has to be higher to even compare to 2 strokes is the problem. so sure, if we up our 2 strokes 40% RPM, we will have problems. But we don't have to, the power exceeds the 4 stroke per cc without needing too. I mean, in your logic (I thought you didn't understand?) my CR500 should be compared to a Chevrolet V8.
A better deal would be to limit the 4 stroke max RPM and make them reliable.
I won't confuse you with facts since you've already made up your mind. Actually their should be no limits other than displacement and weight. Pound for pound and CC for CC. Let's not make this restrictor plate racing.
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I won't confuse you with facts since you've already made up your mind. Actually their should be no limits other than displacement and weight. Pound for pound and CC for CC. Let's not make this restrictor plate racing.
Facts make up minds and my mind surely can change, so please enlighten me with how they have elevated the 2 strokes above where they would have been had there been R&D directly? If you can put facts up, it can change my opinion if it supports what you say. I really would like to know. Since there is only 1 Big OEM who even does R&D on them anymore. Edited: 1 stopped making them, and 3 just remakes the 2005 model, which only 1 is sold in the US. Also, not understanding the CC for CC and pound for pound? Well, atleast the pounds. Should we keep weight constant or try to make bikes lighter? You would be surprised to know what direction the MX racing is going. Just think NASCAR and you will know. Gone will be the days a local pro can jump into a national and say I wanna race. Track changes etc. There will be a lot coming in the next few years. 2 stroke cc for cc against 4 strokes is not on the horizon.
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I took Big Boars post as him just saying that the development / tech level present in 4ts nowadays means that 2ts will be benefiting from much that has been learned from the 4t side of things - AND, that new 2ts when they come, will be a much better thing than they have been in part because of it.
We all know that 2ts HAVE to become cleaner than clean to continue to exist, because of the prejudice against them as being dirty , smelly, polluting things.
The wildy over-square development of 4ts is down to needing the revs to get higher HP levels, and the need for more flow, in and out of the head, to achieve that.
As 2ts inlet and exhaust comes through / out of the barrel, well , the stroke needs to be longer for the inlet and outlets - simplistically put, but accurate.
DFI will change this, to a certain extent, as the limit to fuel getting in is largely overcome, though you still need to get the air in - I think that to get the entire air/fuel charge in by just an injector unit itself would be extremely difficult - the injection system possibly would be bigger, more complicated than the engine itself - not that I am much of a motor man, my engineering experience and qualifications are more on the fabrication/chassis side of things, so I'd defer to others.
I've 2 good friends who are, respectively, a thermo dynamics specialist/engineer, and a EFI/DFI specialist / engineer. Our conversations with regards to 2t development are always interesting - neither are 2t devotees, but both, from their pure engineering points of view, believe that the 2t has a great future - moreso than 4ts, if only government/public prejudices are overcome, and manufacturers with a total commitment to 4ts can be "dealt' with - their words, not mine!
I doubt we will see such over-square dimensions on 2ts as 4ts, as they don't need it, but the DFI outboard motors are slightly over-square (ironically, I think some that I checked quite a while ago, pretty much echoed the over square dimensions of a CR500 - an engine that was quite an anomaly amongst big capacity 2ts).
Interestingly, the DFI 2ts , are using bigger capacity engines than the 4ts. I'd say it's a result of outboards being rated in HP, not capacity, and as the 2ts are so much lighter, they can go to bigger engines (yet Still be lighter!), for their under-stressed nature when delivering the HP level required, whilst giving all the benefits of more torque that the big engine delivers ( to add to the higher torque a 2t has, over a comparably sized and tuned [level of] 4t).
It will be interesting to see what happens with 2t tuning.
The rumours surrounding the Husaberg DFI 230 & 370 have them as having a straight pipe - no expansion chamber. This is the sort of thing I've discussed with my above mentioned friends. There may be a lot of different approaches to 2ts with the advent of 2ts - DFI can mean that the scavenging effect of a chamber will not be needed to 'reclaim' the lost fuel charge from the exhaust port, and the efficiency this gives negates the need for a chamber - ie: the 2t will not need to have such 'exotica' on it. A trapping valve exhaust port can add to this - combinations of these and AST and FAST tech means there will be potential for myriad combinations. My mates do also say that you'll still be able to get even more power with the use of a chamber, most notably when not using a trapping valve, as air/oxygen used to scavenge out the exhaust can be reclaimed to get it back into the engine. As both are also practicing academics, their maths escape me at times, as my math levels have decreased to that of just force vector analysis etc - if you don't use it, you loose it, is so very true.
Any way you look at it, Anybody who says 2t are at the end of their development is a fool. The variety of options that manufacturers/engineers have available to them is astounding. With respect to Mitch Payton, his assessment only applies to the old school 2ts which we currently are left with. And those comments were probably made a few years ago. Well do I remember many quotes attributed to Mitch, calling the YZF250 'cheater bikes' when he had only the 125 Kawi to do battle with it - mind you, he and his riders did damned well with it, and JS made the other riders look a bit silly the last year he rode the 2t (and , yes, I know he used a 4t for the last round at Glen Helen that year - after he'd wrapped up the title on one of the few 2ts still on track).
You can bet Honda will be lobbying even harder to keep 2ts from being given capacity equivalency - they are so committed to 4ts. Mind you, if it came to it, they still probably have more 2t engineering innovations locked up than anyone.......The EXP / ARC technology was probably just the tip of the iceberg. :'(
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I took Big Boars post as him just saying that the development / tech level present in 4ts nowadays means that 2ts will be benefiting from much that has been learned from the 4t side of things - AND, that new 2ts when they come, will be a much better thing than they have been in part because of it.
(YES!! Thank you you've passed the audition. The 2 stroke advantage will be hard to ignore. It is green manufacturing,less material to build and maintain. Better fuel efficiency when they're done cleaning them up. But I still love the smell of 2 stroke oil burning. That will be hard to get used to.)
You can bet Honda will be lobbying even harder to keep 2ts from being given capacity equivalency - they are so committed to 4ts. Mind you, if it came to it, they still probably have more 2t engineering innovations locked up than anyone.......The EXP / ARC technology was probably just the tip of the iceberg. :'(
And it's likely I've purchased my last new Honda because of their corporate,uhm........well...................bullying? I've fallen for the European stuff anyway. My Tuono did that.
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Great write up Bearorso.
"I won't confuse you with facts" "But the 4 strokes (have) elevated the state of the art for smokers as well."
On a side note you used present tense not future, it is an opinion not any facts about if or if it will or will not help 2 strokes with 4 stroke development. I will agree that it is possible, but at a varying degree, compared to the last 5 years with only 2 strokes. But believe it is a fact I will not, and being a smart azz about it didn't help your point. I believe the 2 strokes would be further if they continued R&D on them and had to meet new emmissions. We would very likely already see things like DFI etc. Those are already on Diesels etc. Look at snowmobiles, boats and Lotus. Focusing on 2 strokes.
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Bye the way bearorso. I was gonna mention the CR500 because I have one :-) They even had shorter strokes when they first came out. Many people said those were more abrupt. I think most of the current 2 strokes were undersquared because of years of trying all different ways, showed them that current bikes give the best overall power, and smoothness together.
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I think I get what your saying bearoso, and I agree. If 4 strokes were never produced, than I think that 2 stroke MX bikes wouldnt have seen much development in the past 7 years. Just look at it this way, I'd say 2 stroke development stopped on average around 2003-2004. If they had continued to be developed up through 2010 the bikes would have had some cooler plastic, and all of these "updated" 2010 2 strokes would have had aluminum frames.
Just look at the difference in bikes between 1993, and 2000. Not a huge difference.
But now that these cleaner, smoother, and more torquey motors have been developed and the games been elevated, albeit a displacement handicap. The MX world can't go back to 2003 now. So that means 2 stroke manufacturers need to hit the drawing boards, and give the people what they want.
And reading bearoso's post it sounds like there's great potential.
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KTM guy, I agree, although did the clean air emmission talk come before or after the 4 strokes came into play? My belief is, that no matter with 2 or 4 strokes, the emmissions was gonna be directed this way. It was just a matter of time. So according to DC, the big OEM's said we have 1 of two directions to go and they chose, well you know. But Tiki on vital will tell you that, emmissions even though was used as a bogus reason to push the 4 strokes, it was still really being pushed. So, that points to the things like EFI in the 4 strokes etc. It was coming on a 2 or 4 stroke most likely either way. I guess the real question, is what advancements besides emmission type things, will the 2 stroke gain from these 4 strokes? I think frames maybe, had a llloooong conversation with my 4 stroke loving friend last night about that. I am not sold, although he is, that the 4 strokes or just years of developement have made the chassises better and handle better. I am not sold, because the handling is different on a 4 or 2 stroke, but he disagrees.
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I'm not surprised they went with the 4 stroke route. All the OEMs have gone down the EFI road with their street bikes for years. And then to top it off some crazy New Englander showed up to Vegas race on a 4 stroke works bike and waxed everybody.
The things that keeps me off of them is the weight, boring power delivery, and I can't work on the bastards!
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I'm not surprised they went with the 4 stroke route. All the OEMs have gone down the EFI road with their street bikes for years. And then to top it off some crazy New Englander showed up to Vegas race on a 4 stroke works bike and waxed everybody.
The things that keeps me off of them is the weight, boring power delivery, and I can't work on the bastards!
Oh, when it comes to money, I definitely see why. But they didn't look at the big picture. Running off people who blow their new bike up and can't afford rebuilds. People chosing not to buy a new bike every year because of cost. Things like that. They saw money for parts, the ability according to my source for Honda, to use street bike parts like valves etc. Basically less retooling and stuff.
Damn Doug Henry, too bad we all like him so much, or maybe we'd direct our hate towards him. LOL
I just traded my XR600 off because I couldn't stand the thump thump feeling when coming out of corners etc. My friend said you like other street bikes, I was like, well... hmmm well those are in some ways more like 2 strokes because they fire like a 2 stroke because they have opposite pistons firing so I guess that is why.. I just couldn't stand my XR and hopefully the XR200 goes down the road today.
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I've always thought that the CR500 was loosely based on the 250s, stemming from the Mugen 360 kits, Honda never really putting much effort into it, what with the short stroke etc. But being a 500 2t, power was never a problem.
I know that a lot of privateers who continued to use CR500s in the GPs, prior to the arrival of the CRF450, actually ran their bikes with a smaller bore, with capacity of between roughly 400 to 440. Christian Burnham (sp?) was quoted as running a de-bored 500 , I think with the Sarholtz team, saying it was the best 2t engine he ever used. It appeared in a 4t/2t article to my recollection, the British Moto magazine a couple of years ago.
I first thought you were directing the 'Facts" thing at me, and was a bit puzzled, but caught on it was between you and Big Boar.
I think we are all on the same side, just misreadings, misunderstandings.
I could easily misinterpret Big Boars point about tuning a CR250 (with my belief that the current/non current 2ts have a comparatively higher state of tune than 450s because they have to, to compete against engines that are so much bigger) to the same level as a CRF450 - believing, as I do, that with the current level of 4t tech ( that is still going to progress vastly), that 450s are at very low relative states of tune, being that no one could use all the power that they could get out of a 450 even now - that's always been the case with any open classer, and always will be.
I remember reading Dave Thorpe's column in Dirt Bike Rider years ago, when he'd write each year that the Honda engineers would present him with an 80/90+ HP engine for initial testing, and he'd get them to back off and just give him his 60/70 HP engine that he favoured.
But then I slowed down and just realised Big Boar was referring to piston speeds, and , of course, a 72mm stroke would put a hell of a lot more stress on things than the 60mm (not sure exactly what it is?) stroke of the CRF, at the same revs if you tried to spin the 2t that hard. I think the hard rev limiter on a CRF is somewhere near 11400!!!!!! :o(or at least one of the 010 450s have that as their cut out). That's fairly mind blowing on a single intended for use on the dirt, don't you think? So as my favourite penguin would say , Kaboom, Kaboom!
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For sure for sure on about everything you just wrote. I think the 400 2 stroke with an electric start, DFI and counter balancer to negate any vibration, would be the best open classer ever built. Hmmmm, just thinking of how good that would be makes me dreamy. LOL 8)
By the way, via a current pro mechanic of the big 4, they do still detune these 450F's. I'm guessing the new 350F will be about the same HP as the raced 450F's just by tuning up a 350F and down a 450F. Why oh why couldn't they have made life easier with keeping with the 1970's - 1994 rules of 360cc. >:D
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As far as the RPM thingy, my friend (the 4 stroke lover) and I had thought about coming up with a bolt on kit for the 4 stroke bikes to make them more reliable. First, the piston would be heaver and stronger, thus would slow the RPM down. Then a lower rev limiter. But my only fear was that the crank would have a harder time because of the heavier piston. I guess it might negate itself with the slower top rpm's but heavier piston. That idea made it one night on the phone. LOL
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Great write up Bearorso.
"I won't confuse you with facts" "But the 4 strokes (have) elevated the state of the art for smokers as well."
On a side note you used present tense not future, it is an opinion not any facts about if or if it will or will not help 2 strokes with 4 stroke development. I will agree that it is possible, but at a varying degree, compared to the last 5 years with only 2 strokes. But believe it is a fact I will not, and being a smart azz about it didn't help your point. I believe the 2 strokes would be further if they continued R&D on them and had to meet new emmissions. We would very likely already see things like DFI etc. Those are already on Diesels etc. Look at snowmobiles, boats and Lotus. Focusing on 2 strokes.
I'll not bother you anymore. If I wanted to argue I'd find a woman.
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Nice post Bearorso :)
Yes the DI outboards are very under stressed. They are not actually bigger then comparable 4/S, most are smaller.
With engines designed for a HP output instead CC's they have kept the 2 stroke large to produce torque.
As an example the DI 200HP makes 40HP more between 3000-45000 rpm then a 225HP 4 Stroke.
To make things confusing the manufactors are aloud a 10% variation from the advertised HP.
A big bore DI 2/S Dirtbike would be able to pump out 65HP very easy and be as smooth as silk.
That thing would eat up any track, be lighter and more reliable then any 4 stroke.
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Hmm, that sounds like a description of-
But I'm not supposed to say that, am I?