Post by: citabjockey on April 21, 2013, 05:55:23 PM
http://www.cycleworld.com/2013/04/18/superbikes-of-supercross-racing-technology-vs-costs/
This is a bit of background on SX bike development, including some detail from RV's team.
But -- scroll 2/3 of the way down the article to this little tidbit:
Osterman also said some of the things I?ve been hearing from others about four-stroke MXers. ?When a four-stroke makes a noise, it?s usually too late. There?s so much going on in them, it?s going to cost you. If you grenade a four-stroke, you might as well buy a new one.?
Four-strokes, which fire only every other revolution, have to make up for this by revving higher. When something goes bad inside, all that extra kinetic energy goes into breaking things. Would some form of electronic early warning be too expensive?
World Superbike tech inspector Steve Whitelock used to manage AMA Supercross. He said MX dads were constantly calling and writing him, urging a return to two-strokes. If a two-stroke seizes, you buff the aluminum off the bore, put in a new piston and rings, and you?re running again in 30 minutes. But with a four-stroke, when a valve touches the piston and breaks, it can cascade, wrecking the head, cylinder, crankshaft and crankcase. Just take it to the dealer and write ?get running? on the R.O.? How many times can dad?s plumbing business cover that $4000 bill? Some families put hundreds of thousands of dollars into their sons? riding careers, but in this game, financial sincerity is no guarantee of success.
Yep.
Post by: eprovenzano on April 21, 2013, 06:08:20 PM
Post by: Stusmoke on April 22, 2013, 02:01:09 AM
Post by: Smithdad on April 22, 2013, 03:56:40 AM
That is the world we USED to live in!
Post by: SwapperMX on April 22, 2013, 04:51:41 AM
Post by: VintageBlueSmoke on April 22, 2013, 10:44:38 AM
Ahem...flame away!
Post by: SwapperMX on April 22, 2013, 11:32:37 AM
He says "It?s like the old situation with carbureted bikes: Carbs are only so good. EFI completely erased all those problems. I welcome it. It?s going to make the end user?s stuff better.?
Ahem...flame away!
As bad as it sounds Vintage, this is the general riding public's opinion. One less thing to have to do to your bike, i.e, jetting it constantly. It has seriously affected Yamaha's sales of their 250f's. Purely because they are still carburetted. Look forward a few years, and imagine there are several companies that have had fuel injected two strokes for a couple of years. Do you think people who were looking at buying a new bike would still want a carb'd two stroke. No, they would want the injected spec bike, as it's one less thing to worry about. Regardless of whether it is necessarily better.
Post by: Stusmoke on April 23, 2013, 12:52:44 AM
He says "It?s like the old situation with carbureted bikes: Carbs are only so good. EFI completely erased all those problems. I welcome it. It?s going to make the end user?s stuff better.?
Ahem...flame away!
As bad as it sounds Vintage, this is the general riding public's opinion. One less thing to have to do to your bike, i.e, jetting it constantly. It has seriously affected Yamaha's sales of their 250f's. Purely because they are still carburetted. Look forward a few years, and imagine there are several companies that have had fuel injected two strokes for a couple of years. Do you think people who were looking at buying a new bike would still want a carb'd two stroke. No, they would want the injected spec bike, as it's one less thing to worry about. Regardless of whether it is necessarily better.
Exactly. Whether or not EFI on the four strokes is better has become irrelevant. The public is sold on the idea. Not having to jet everytime you go to a different race is awesome! Mankind is forever seeking ways to make their life easier, and EFI does that in a big arse dose.
Post by: fabbo on April 23, 2013, 03:44:29 AM
Any way just my .02 cents worth.
Post by: Stusmoke on April 23, 2013, 07:49:04 AM
Post by: VintageBlueSmoke on April 23, 2013, 09:56:31 AM
Having said that, being able to take something apart, reassemble it - even in "bum crack nowhere", is comforting. However, having been there, and having my known and reliable carb fail. I still had to hike out and come back for it - more than once. Conversly, if I had FI (et al), my bike might not have failed in the first place...or it might have failed with something else...like something to do with the FI, but I still would have had to walk out.
Stu brings up the point of weight and initially I disregarded it as a "Stuism" but although EFI doesn't weight any more than a carb, a battery is required to run the fuel pump - and that is usually unacceptable weight if you don't require a battery anyway (e-start baby!).
I've said it before but in those transportation mediums that have already converted to FI (automotive and marine), reluctance was initially high - even in sports, but eventually the advantages outweighted the disadvantages. Everybody, even desert racers and boaters, who actually go to "bum crack nowhere", now use FI.
Post by: TMKIWI on April 23, 2013, 10:21:38 AM
Stu brings up the point of weight and initially I disregarded it as a "Stuism"
I like. A new word for TSM.
but although EFI doesn't weight any more than a carb, a battery is required to run the fuel pump - and that is usually unacceptable weight if you don't require a battery anyway (e-start baby!).
EFI/DI can run with out a battery.
Rare earth magnet stator.
e.g ETEC's have enough power from the stator to fire up the EMM in 1/4 of a revolution. No battery needed.
Post by: motoxr377 on April 23, 2013, 03:26:03 PM
"Stuism"
LOL
Post by: Dirtsaw on April 23, 2013, 04:10:40 PM
??Post by: VintageBlueSmoke on April 23, 2013, 04:49:20 PM
No car or truck today comes with a carb. Why do we motorcyclists have to be left with pre-1980's technology?
Post by: 2T Institute on April 23, 2013, 04:49:48 PM
A buddy of mine has a Husky 310 with fuel injection. Brand new. Had to get it remapped just to change the pipe. And the dealer screwed it up the first time they tried. Imagine joe schmo trying to do it in his garage.
Erm just get a Power Commander
Post by: Dirtsaw on April 23, 2013, 05:49:45 PM
Post by: Micahdogg on April 23, 2013, 07:12:38 PM
BTW, you can't really compare the infancy of EFI to what will be in another 5-10 years. When EFI hit the automotive world, it wasn't a slam dunk in the first year. Fastforward through the crude Throttle Body Injection of the 70's, to the "atari" type systems of the 80's and finally in the 90's you start getting some real control. Bikes will evolve the same way.
Post by: Dirtsaw on April 23, 2013, 07:33:45 PM
Post by: Micahdogg on April 23, 2013, 07:42:46 PM
Post by: factoryX on April 23, 2013, 07:45:26 PM
Some say it will make a 2 stroke more 4 stroke like. Who the hell wants that?Uh plenty of people, why they went to 4 strokes to begin with nevermind they've been developed to mimic a two stroke delivery. And you're looking at the two stroke the wrong way. The reason why the two stroke engine is awesome is its tunabillity. You can set it up to run like a trials motor or a top fuel funny car. All EFI would do is work with that. As for its complications, EFI is annoying. Its awesome once its going, but you'll have to make as many changes as you would fiddling with a carb after installing a performance part. After a point you have to ask why? I am both for and against EFI, I think I'll stick with a smart carb, they're results are amazing for both 2/4 stroke. People are even converting EFI set ups back to carb just to run one. GasGas contacted APT after seeing the success on the gasgas forums, and are debating about running them on their bikes.
Post by: Dirtsaw on April 23, 2013, 08:12:48 PM
WTFactoryX are you the dude in Bend, OR??? If so are you ridin the ISDE this weekend?
Post by: vetman on April 23, 2013, 10:24:48 PM
Post by: fabbo on April 23, 2013, 10:41:46 PM
Post by: Jeram on April 24, 2013, 12:21:39 AM
Post by: Suzuki TS250/185 on April 24, 2013, 12:33:52 AM
Apart from the fuel and air, notable moving parts are the float assembly and valve, the slide with it's attached needle, and the spring between the top of the slide and the cap which returns the slide and needle to the closed position along with, or in the absence of gravity, when the throttle is closed. Those are the full time workers, the choke slide is a part timer who hardly has to do anything.
Because of that robust simplicity, carburetor failures are so unlikely that it's almost like worrying that you won't get to go riding because of a catastrophic number plate failure... In all the time I've had bikes and hung with groups of people who rode, I have never known "Carburetor failure" to stop a ride from taking place or end one suddenly with no way home. Both of those scenarios seem pretty remote, judging from my own experience and that of everyone I know.
But don't take my word for it, do a fun study of your own! - Go to "The Motocross Vault" on YouTube and dig up ALL of the great 2 Stroke motocross and supercross races you can find and watch them all. - You'll be waiting a REALLY long time (Forever) before you're watching a race and you see someone grind to a halt due to "Carburetor Failure". You'll probably be waiting even longer than that before you're watching a 2 Stroke race at the drop of the gate, and one guy's bike just sits there, engine suddenly dead due to "Carburetor Failure", while he kicks and kicks.
To see those kind of funny failures happen with some regularity, you have to fast forward to more recent Foopercross and Mowercross, and the handicapped, crutch bristling barges of today's weak scene. The complicated, stupid fuel injection systems that were supposed to be a bandaid and a shot of caffeine for the lumpy and flawed induction and power curve of the Fooper, fail like balloons in a preschool. I don't even watch modern pro MX and SX that much because of how boring it is, but I've seen Justin Barcia, Ryan Dungey, John Dowd and Vince Friese and many more pro riders each end up stranded on the starting line (Barcia more than once!) because their ultra-dependable Rube Goldberg fuel system crapped out suddenly..... And that was after a whole squad of professional wrenches had hunched over the junk for hours and days preparing! Where would that leave someone who doesn't have a squad of professional wrenches?
Oh... I can't WAIT for that trouble-free fuel injection!
His bike wasn't going anywhere.... And speaking of bikes that don't seem to be going anywhere...
I'm not trying to muckrake, but there's a lot of BS that people spew about all the problems "You're going to have", with a carbureted bike and they are almost always fairytales or miss labeled, unrelated problems. Then you get the same people singing hymns about fuel injection and making false comparisons that use Foopers or some "SS A.A.R.P." center console fishing boat engine as examples.
When Foopers with fuel injection were first introduced, the hype was "You'll never have to worry about anything fuel mixture related ever again, because the system with adjust to anything"
BUT, then that turned out not to be true, because the bikes needed to be adjusted to deal with heavy load conditions like deep sand and some other things like that, usually to richen the mixture and keep the operating temps from spiking so high that the pieces of crap would eat themselves alive .... SO they started including alternate couplers and other poo, so that those Fuel Injected Foopertroopers could "Re Jet" their bikes for those special conditions. ...So as it turned out, they still have to tune and "Jet" their Foopers occasionally, and they get a reduction in reliability and serviceability, an increase in weight, and an increase in cost in the not-a-bargain to go along with it.
And the hype that 4 stroke trolls like to harp on about how you CONSTANTLY have to keep trying to jet your 2 stroke.... Well, that's a load a manure too.
On a 2 stroke streetbike, do you really think you'd have to start by jetting your bike in Seaside Heights, then stop in Easton, PA and re jet because you gained some elevation, then stop again in Hazleton, PA to re-jet again??? No, you wouldn't... You'd be too busy just riding along and enjoying yourself.
Post by: Stusmoke on April 24, 2013, 12:54:13 AM
"Stuism"
LOL
I like it
Its too far back to quote but the one VBS posted with the stuism remark in it I agree with. Its especially useful on long treks where you could be going up and down several thousand feet.
Post by: citabjockey on April 24, 2013, 03:44:51 AM
But, all kiddin aside, you make some very strong arguments. Not the least of which was the fact that you really don't have to mess with a two stoke bike's jetting once its really setup. I don't know that I have ever messed with different jetting (other than dropping a needle one notch to ride at 8000') for "local conditions".
On the other hand, most folks never have to think about their FI automobile engines. And they don't break at the start line either (or when you go to pull out of the garage to drive to work). That's the magic of large sample sizes and years of testing -- a hurdle the FI bikes have yet to clear. I can confidently predict that when the FI on these four strokes is as common as that on cars it will not be breaking -- at least not at the rate it seems to now.
Now, if I could have my two stroke motocross bike, AND my two stroke single track tail bike, and my two stroke dual sport bike and -- heaven fobid -- by two stroke street bike I will be one smoking happy camper. Problem is that all save the first example I can't have them in CA. We may all have our opinions on environmental regulations but the fact remains they are here to stay and they are quite probably going to get even more strict. So, for me to have my two stroke cake and ride it too my bike would probably have to have a system cleaner that what you can manage with a carb. I would be fine with a carb. I have been for years. BUT I can't have the bikes I want with them.
So if FI/DI or some other wizzbang upgrade appears that can hoist the valveless wonder motor onto the green sticker pedestal , AND it doesn't break every 10 hours...
I am going to buy one.
The carburetor on the typical two stroke motorcycle engine is extremely unlikely to fail, because it does it's complex job with very few moving parts, no stupid fuel pump, and with the fuel and the air both at atmospheric pressure.
Apart from the fuel and air, notable moving parts are the float assembly and valve, the slide with it's attached needle, and the spring between the top of the slide and the cap which returns the slide and needle to the closed position along with, or in the absence of gravity, when the throttle is closed. Those are the full time workers, the choke slide is a part timer who hardly has to do anything.
Because of that robust simplicity, carburetor failures are so unlikely that it's almost like worrying that you won't get to go riding because of a catastrophic number plate failure... In all the time I've had bikes and hung with groups of people who rode, I have never known "Carburetor failure" to stop a ride from taking place or end one suddenly with no way home. Both of those scenarios seem pretty remote, judging from my own experience and that of everyone I know.
But don't take my word for it, do a fun study of your own! - Go to "The Motocross Vault" on YouTube and dig up ALL of the great 2 Stroke motocross and supercross races you can find and watch them all. - You'll be waiting a REALLY long time (Forever) before you're watching a race and you see someone grind to a halt due to "Carburetor Failure". You'll probably be waiting even longer than that before you're watching a 2 Stroke race at the drop of the gate, and one guy's bike just sits there, engine suddenly dead due to "Carburetor Failure", while he kicks and kicks.
To see those kind of funny failures happen with some regularity, you have to fast forward to more recent Foopercross and Mowercross, and the handicapped, crutch bristling barges of today's weak scene. The complicated, stupid fuel injection systems that were supposed to be a bandaid and a shot of caffeine for the lumpy and flawed induction and power curve of the Fooper, fail like balloons in a preschool. I don't even watch modern pro MX and SX that much because of how boring it is, but I've seen Justin Barcia, Ryan Dungey, John Dowd and Vince Friese and many more pro riders each end up stranded on the starting line (Barcia more than once!) because their ultra-dependable Rube Goldberg fuel system crapped out suddenly..... And that was after a whole squad of professional wrenches had hunched over the junk for hours and days preparing! Where would that leave someone who doesn't have a squad of professional wrenches?
Oh... I can't WAIT for that trouble-free fuel injection!
His bike wasn't going anywhere.... And speaking of bikes that don't seem to be going anywhere...
I'm not trying to muckrake, but there's a lot of BS that people spew about all the problems "You're going to have", with a carbureted bike and they are almost always fairytales or miss labeled, unrelated problems. Then you get the same people singing hymns about fuel injection and making false comparisons that use Foopers or some "SS A.A.R.P." center console fishing boat engine as examples.
When Foopers with fuel injection were first introduced, the hype was "You'll never have to worry about anything fuel mixture related ever again, because the system with adjust to anything"
BUT, then that turned out not to be true, because the bikes needed to be adjusted to deal with heavy load conditions like deep sand and some other things like that, usually to richen the mixture and keep the operating temps from spiking so high that the pieces of crap would eat themselves alive .... SO they started including alternate couplers and other poo, so that those Fuel Injected Foopertroopers could "Re Jet" their bikes for those special conditions. ...So as it turned out, they still have to tune and "Jet" their Foopers occasionally, and they get a reduction in reliability and serviceability, an increase in weight, and an increase in cost in the not-a-bargain to go along with it.
And the hype that 4 stroke trolls like to harp on about how you CONSTANTLY have to keep trying to jet your 2 stroke.... Well, that's a load a manure too.
On a 2 stroke streetbike, do you really think you'd have to start by jetting your bike in Seaside Heights, then stop in Easton, PA and re jet because you gained some elevation, then stop again in Hazleton, PA to re-jet again??? No, you wouldn't... You'd be too busy just riding along and enjoying yourself.
Post by: factoryX on April 24, 2013, 04:08:55 AM
That's great. Just like Dungy and his new air forks? Heh. No one is arguing a computer can't do a better job at air/fuel mixtures. I just don't want to see it as the only option someday because of the added expense and guess work. Jetting charts are a no brainer and jetting can be changed inside of 10 minutes no matter where you are without some electronic device wand batteries..WTF, I keep forgetting to check OMRA. Have a link?
WTFactoryX are you the dude in Bend, OR??? If so are you ridin the ISDE this weekend?
Post by: Dirtsaw on April 24, 2013, 05:25:45 AM
Too late for the ISDE. Numbers came out last night and no post entry. I'm on minute 5. Next race out there is at the ODOT pit and it's a Hare & Hound 108 miles on May 19th... It's on the OMRA schedule as the Monkey Butt XC...
Post by: VintageBlueSmoke on April 24, 2013, 08:53:19 AM
What you are missing about the simplicity of carbs are that they are so 'simple', they are only perfect at one point in the atmosphere at one point of the throttle opening. Eveything else is a compromise. Sure your carb'd bike runs fine because a it is like a bell curve. However, with FI fuel/air metering becomes more linear.
Yes, you do add other parts that could fail but the technology has come along far enough where those failures are rare.
Post by: TMKIWI on April 24, 2013, 09:35:18 AM
Bloody electronics.
Post by: VintageBlueSmoke on April 24, 2013, 11:12:39 AM
Post by: Micahdogg on April 24, 2013, 04:02:37 PM
Here is some food for thought:
-1970 Chevy Vega, carbed 2.3L making 90HP.
-1990 Chevy Corsica, injected 2.2L making 120HP
-2010 Chevy Cobalt, injected 2.2L making 155HP
That is progress. Anyone care to take a stab at how much the two stroke has progressed in the past 20 years? I'm not talking, chassis or ergo's - just straight up motor progress. Cause from where I sit it appears very little has changed - rather it has just been refined.
I love two strokes, but not because they are relics. I know the design is superior - that is why I choose them. But we don't have to become stagnant.
-2013 KTM 250sx, carbed, 49HP
-1993 Honda CR250, carbed 45HP.
Go back to 1984 and the CR250 was advertised has making 43HP. So in 30 years, the motors are making 14% more power? That's just not acceptible. Would anyone have bought a 2000 Chevy Cavalier with a carbed 2.2L that made 100HP?
Post by: factoryX on April 24, 2013, 04:41:07 PM
Post by: Suzuki TS250/185 on April 24, 2013, 07:44:55 PM
-1970 Chevy Vega, carbed 2.3L making 90HP.
With a compression ratio of 8.0:1 and 2 valves per cylinder
-1990 Chevy Corsica, injected 2.2L making ***120HP???*** ***WRONG ANSWER*** It actually makes only 95 Horsepower - BECAUSE of a substantial compression ratio increase over the aforementioned engine, to 9.0:1 (That's an 11% increase in compression) also 2 valves per cylinder
So... the Vega had 1/22 more displacement and 11% less compression, and it produced 90 Horsepower..... And the Corsica with Fuel Injection, 1/22 lesser displacement, and 11.2% higher compression produced 95 horsepower???
That's really not impressive... After all, any of our bikes could surely produce 5% more horsepower if granted a 11.2% increase in compression.
Post by: Micahdogg on April 24, 2013, 07:59:46 PM
)Post by: citabjockey on April 24, 2013, 08:07:13 PM
Post by: Micahdogg on April 24, 2013, 08:09:51 PM
Post by: Suzuki TS250/185 on April 24, 2013, 08:59:39 PM
All I'm saying is that the increase in compression accounts for the increase in horsepower. With that much difference in the compression ratios in favor of the fuel injected example of nearly equal displacement, it doesn't appear that there was much gain, if any, resulting from the fuel injection. It appears to have resulted, in fact, from other differences in design.
The other demonstrative precedent is the fact that 4 Foopties haven't gained any horsepower as a result of fuel pumps, fuel pressure, and the resultant, frequent failures associated therewith...
Post by: Micahdogg on April 24, 2013, 09:40:06 PM
I still contend, despite the teething process that fuel injection will go through - it will lead to increased power and efficiency alone. And I'm happy with a carb on my bike.
Post by: factoryX on April 24, 2013, 10:31:57 PM
Post by: SwapperMX on April 24, 2013, 11:56:13 PM
4 Foopty, love it !!
Post by: 2T Institute on April 25, 2013, 12:20:47 AM
A 5.0 litre V8 fitted to many cars here make way more HP than they ever did on carburetor. V8 Supercar race versions were about 120HP up on carbed versions with a 9.0:1 comp cap and 7500 rpm rev limit.
Fuel injected 4T MX bikes will be the same more predicable torque to the rear wheel at any throttle opening.
Post by: citabjockey on April 25, 2013, 02:27:45 AM
For two strokes we have a different ballgame. Very few examples of FI two strokes exist as models for guys (like Uniflow) on which to base their experiments. yes, I know there are some outboards and some snow machines but compared to the ocean of automobiles that have had FI for a couple of decades now the amount to two stroke FI knowledge is quite small. So the "issues" seen currently with injection on the 4-stroke MX bikes are orders of magnitude more difficult for two strokes I would think -- just because this is a NEW art.
BUT -- a FI (or heaven forbid DI) two stroke may have much larger advantages over carbie bikes than the FE 4T had over the carb 4T. Features like 30% smaller gas tanks and ability to get green sticker registrations in CA. These are features that have far more impact for the average rider than the FI on 4 strokes have. I for one welcome the coming change -- if it comes to pass before two stroke bikes disappear completely.
Again, for myself, I fully embrace the functionality, reliability, simplicity and serviceability of existing carbs. I would be fine keeping them and think that having CARB and EPA worrying about emissions from such a tiny set of ICE's is ridiculous. BUT such wishful thinking is unrealistic. I really believe that for the long term continued production of two strokes we must have a technology jump. Eventually.