Two Stroke Motocross
Two Stroke Motocross Forum => General Two Stroke Talk => Topic started by: JohnN on January 12, 2010, 07:07:47 AM
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Found this on KXriders....
There is a big difference in the aluminum vs. the steel frame weight. The steel K5 frame weighs 19 lbs 7 ozs and the KX450f frame weighs 24 lbs 11 ozs. I weighed them with the same scale 30 seconds apart. There is no typo or mistake, the steel frame is lighter. The KX500AF is 5 lbs lighter than the KX450f. My AF frames are about 1 lbs lighter than the KX450F and probably most other KX500AF's. There you are and there you have it.
JFAB
http://kxriders.com/forums/index.php/topic,6848.0.html (http://kxriders.com/forums/index.php/topic,6848.0.html)
So aluminum frames do not help save weight.... hmmmmmm!
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I think some one wrote a long term test where the author ( :-X :P) called the aluminum frame craze was a farce.
Maybe I am mistaken though :o :-*
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I never really got the idea of aluminum frames. i hear people talk about better rigidity and that stuff, but i t seems that one year they make changes to reduce rigidity and next year other changes to increase rigidity. just my 2 cents or whatevvah.
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Good to see that a reader from another website found this site and posted a link to mad's report below his question so others could read the report.
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I think some one wrote a long term test where the author ( :-X :P) called the aluminum frame craze was a farce.
Maybe I am mistaken though :o :-*
Speaking of which, I do hope you haven't forgotten Part III...
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Not surprising.I know this will never happen but I wish a company would produce a nice steel framed, air cooled,conventional forked bike for us woods guys.Like mentioned every year they try to provide more flex in the chassis,forks,triple etc..I do realize that a dedicated woods racer would differ from a mx/sx bike as far as rigidity etc..Lets not forget it has to be a 2stroke.BBBBBBBBBBBRRRRRRRRRRRRRAAAAAAAAAAAAAAAPPPPPPPPPPPPPPPPPPPPPPP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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Hmm...
Steel frame
Conventional Forks
Air Cooled
2 Stroke
Sounds like a Maico to me. From my experience, though, the best woods bike in the world, flat-out, is a '76 or '77 400cc model. They've got an ass-load of torque right off the bottom and lots of fun power to play around with up top, but won't blow your head off. My dad describes the handling as, "The only bike that rides like a unicycle. Put the front wheel wherever you want, and ignore the rear, because it'll always do the right thing." They don't have the longest suspension travel in the world, but in the woods you don't need it, and the low seat-height gives a much better sense of confidence when the bike stops for whatever reason (rock, root, seizure, whatever) and you need to put your foot down. The worst part on the bikes are the foot pegs, and that tells you something about what the rest must be like. And they're light! My dad's 250 (yeah, it's just a 250) is right around the 200lb mark. High- or Low- pipes available.
(http://www.vintagemaicos.com/newgallery/images/1976%20Maico%20AW440%20Jim%20Hunt.jpg)
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Hello Everyone,
Yes, it appears that not much weight savings gain is made in the switch from steel or chromoly to aluminum.
But, there IS one MAJOR DIFFERENCE, Fatigue Life. They don't mention that in their colorful and flashy advertising. I would much rather haul myself around on a well engineered frame that doesn't have aluminum's Cumulative Fatigue Damage characteristics. Just out of curiosity, I've been checking into the differences and the more you learn, the worse it gets. It's actually on the edge of being a little scary, not just dissapointing, to tell you the truth.
Put it this way, I really want the SSS forks, but because of the frame I'm glad my YZ's an 04!
Sometimes it feels like the biggest inovation to hit motorcycling lately has been precision planned obselecesnse.
Thanks,
Jim
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Ya, the Steel frames are probably lighter because you need less metal to make it all stronger, the difference is that the steel frames aren't really updated anymore, they are old designs, so... The alluminum frame bikes tend to handle better. Although, KTM makes improvements to their steel frames still. What I am curious to is that, my 2001 cr125 is claimed to be 193 pounds dry weight, but, the KTM which is 9 years newer is 200 pounds, I wouldn't have expected this from KTM, although, the KTM sure does beat my bike in other areas, such as transmission and engine. My engine is kind of getting disappointing...
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I'll never understand the love and admiration for air cooling. Liquid cooling adds a little weight. Adds some hoses. And a water pump. In all my years I have only see one guy get stranded from a hose, and it was OWNER INDUCED.
For what you gain with liquid cooling (more HP, torque, less vibration, longer life and cleaner to name a few) why would you want to go back.
I agree...USD forks (exactly the same as the single shock debacle) was a marketing ploy to get suckers to buy a new bike. And, they still didn't tune the forks for themselves. :o >:D
Chassis not being updated is the fault of the manufacturer. You can achieve the same characteristics with steel as they do with aluminum. They (the factories) all want you to buy new junk, so they stop updating the things they don't want you to buy.
That said, if you compared a new, say 2005 models, steel vs Aluminum, could you tell the difference??
You can't blindfold a rider. But if you could, testing would be more trustworthy for sure.
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Mad,I am aware of the benefits of water cooling.That being said as a woods bike I wouldn't mind an air cooled engine.I have ripped radiators off after some big crashes in the woods the ended my day of racing.So you add up the cost of the ended day and the cost of repair during the week could get a little costly.maybe I am just getting cheap in my old age. :)
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Mad,I am aware of the benefits of water cooling.That being said as a woods bike I wouldn't mind an air cooled engine.I have ripped radiators off after some big crashes in the woods the ended my day of racing.So you add up the cost of the ended day and the cost of repair during the week could get a little costly.maybe I am just getting cheap in my old age. :)
Buy some radiators guards!!
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My main complaint with water cooling is the simple fact that it's ugly in my eyes. The fins MAKE a bike, aesthetically, and that's how it goes. I can't get used to the thought of having this little blob-of-clay looking thing sticking out of the cases and pretending to call itself a source of power. It doesn't look the part.
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My main complaint with water cooling is the simple fact that it's ugly in my eyes. The fins MAKE a bike, aesthetically, and that's how it goes. I can't get used to the thought of having this little blob-of-clay looking thing sticking out of the cases and pretending to call itself a source of power. It doesn't look the part.
Sounds like my wife when she asks me id her shoes and purse match. I;ll take cleaner and more HP any day. But that's just me.
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Mad,I am aware of the benefits of water cooling.That being said as a woods bike I wouldn't mind an air cooled engine.I have ripped radiators off after some big crashes in the woods the ended my day of racing.So you add up the cost of the ended day and the cost of repair during the week could get a little costly.maybe I am just getting cheap in my old age. :)
Buy some radiators guards!!
Well rad guards are good on side impacts.I'll give you on example where they don't help.on my cr500 I crashed real hard in a rock garden during a hs and flipped the bike 2-3 times bike skipping across the rock garden after that.Well it pushed the pipe up so far that it mangled and tore the mounts off.Might have been better if i didn't have the guards for that one.Doesn't happen often but is costly when it does.
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Weigh a Ducati frame and any modern chink frame. You will be surprised to know that a steel frame is actually lighter if built right. Meaning triangulated.
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One other thing to consider... Metal does fatigue, regardless if its alum or steel... The steel frame is much easier to have repaired then the alum. Most of us have a steel welder and could make the repair if needed, but access to an alum welder would require a trip to a specialty shop.
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I am all over pop-can made frame! Look at the Aprilia 550 ,TM's and the new 4 stroke Yami! :-* They make the bike stand-out and it blends better with everything else!
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Mad,I am aware of the benefits of water cooling.That being said as a woods bike I wouldn't mind an air cooled engine.I have ripped radiators off after some big crashes in the woods the ended my day of racing.So you add up the cost of the ended day and the cost of repair during the week could get a little costly.maybe I am just getting cheap in my old age. :)
Buy some radiators guards!!
Well rad guards are good on side impacts.I'll give you on example where they don't help.on my cr500 I crashed real hard in a rock garden during a hs and flipped the bike 2-3 times bike skipping across the rock garden after that.Well it pushed the pipe up so far that it mangled and tore the mounts off.Might have been better if i didn't have the guards for that one.Doesn't happen often but is costly when it does.
Other than the radiators, would an air cooled bike have finished the day after the same crash? What about the rider? After a crash like that, I go home. I don't get a paycheck from it. I think most guys would call it a day. If it happens to a pro, they keep radiators etc. in the trailer. They would bolt them on and go. Still not seeing the benefit of air cooling.
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mad,i think an air cooled bike would have finished as long as the exhust stayed in the manifold.The rider would have finished also as he had no broken bones.As far as spare rads and replaceing them when you are in a hs in the middle of the woods it is not possible to replace them especially if the hoses are ripped off or the rad is puncutered and puking coolant out of it.As you know you would wind with an overheating problem.Now you would need a top end and a new rad.lol Like i said doesn't happen often and water cooling is not a major complaint and maybe i am just getting old that is why i said air cooled.
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In many cases,steel frames are heavier than aluminum frames-it depends on the frame.Honda's early CR frames were heavy and also way too stiff.In later years,they thinned them out in order to feed some flex in to the chassis.If the bike I wanted had an aluminum frame,I'd buy it though I would prefer a steel.A couple things always bothered me about aluminum frames.One,the aforementioned bolt in the aluminum frame though most have a steel insert though when a friend has one of his spin in the frame of his CRF-well,there it was as the insert was made inside the frame.The other concern was the thickness.The spars look pretty beasty but in most cases the wall thickness is very thin.Having had aluminum frame guards a few times over the years I eventually switched to plastic as my boots tended to rub them either through or paper thin over the course of a season.I couldn't help but wonder how thin my buddys CRF spars had become over 3 years where his knees rubbed against them.Unfortunately he declined my suggestion we drill a hole to measure it-all in the name of science of course.As for the reasoning being it,Honda initially seemed to start it as an engineering exercise but these days it's all economics.Steel frames need to be bent,welded,gusseted cleaned,primed painted etc and have more individual parts.Aluminum frames generally consist of no more than 5-6 pieces that are either cast,forged or extruded.It's more cost effective these days to mass produce an aluminum frame than a steel one.Does anyone honestly think the companies would offer a much more expensive unit that performs the same function no better and charge the same $$ for the bike?Didn't think so.On the other hand,I'm glad my bike has an aluminum swingarm instead of a steel one.Of course,the swingarm is an unsprung unit so you can't really compare them as similar in function either.
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i just hate working on aluminum frame bikes. everything is so hard to get to with those huge spars. as far as air cooled engines, i remember how they over heated in slow going/hard use and then the jetting was all over the place when hot. i don't miss air cooling at all.
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I will certainly admit, an air-cooled bike likes to have some speed on its side. Motocross used to be a faster sport than today, but I imagine a high-rev-low-speed racing environment like Supercross would really put the strain on an air-cooled machine. For the kind of riding I like to do, however, which largely consists of desert and forest roads (yes, you can go from deep forest to barren desert in five minutes here in Oregon) there's always a lot of air flowing over the cylinder.
There are a lot of things I love about my Husky, but I've always been dissatisfied with its cooling. It fell victim to the widespread fin-shaving campaigns everyone was participating in during the early-80s, and it shows. I was drilling my friend on bike identification (because I could) and showed him a string of Huskies, asking for displacement. I showed him a lot of '70s models, then I showed him an '82 250. He thought it was a 125! Even Maico, who were always great with cooling, sold their soul a bit. While their cylinder looked the same, and the fins actually stayed fairly consistent, they constantly removed more and more of them. Take a look at an '83 and compare it to a '74 radial. Have a look at the distance between the lowest fin and the cases. On the '83, you could put a beer there. On the '74, you might fit slice of bread, if you mash it with your fingers.
No wonder everyone switched to water cooling. The air cooling didn't work, because they took 50% of the cooling surface away whilst cranking the power ever higher! That's not to say the big fins worked as well as radiators; they didn't, but they got the job done as well as needed, and gave the bikes yet another layer of personality that we have been duped out of lately. Well, I should say, the personality that the rest of you have been duped out of. :P
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I love fins......
(http://top-10-list.org/wp-content/uploads/2009/08/The-Little-Mermaid.jpg)
(http://www.popartuk.com/g/l/lghr12355%2Bdolphin-sunset-steve-bloom-poster.jpg)
(http://www.rossgrahamphotography.co.uk/pics/hotrods/59CadillacFins.jpg)
(http://www.bottom-time-scuba.com/images/fins/fins_mako.jpg)
Just not on dirt bikes.... sorry :D :D
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You forgot some.
(http://cdn-www.airliners.net/aviation-photos/photos/4/9/2/1178294.jpg)
(http://www.giftsandfreeadvice.com/free_advice/wp-content/uploads/2009/10/mako-shark.jpg)
(http://www.naval-technology.com/projects/ohio/images/ohio1.jpg)
(http://motors.opferman.com/About/News/07052009/DSC03222.jpg)
(http://christopherjagmin.com/download.phtml/38/fin.png)
By the way, did you notice that three out of the eight "fin" pictures we posted were associated with Maico (or Mako)? There's the Mako brand fins, the Mako shark, and of course, the Maico motor!
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I've seen a number of steel frames crack and even break in half, even a relativly late model KTM.
Can't remember seeing an alloy frame broken in half.
With the obstacles you encounter in modern motocross ie jumps with 100ft or over gaps strength is a big issue.
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Total NZ - for your viewing pleasure!! ;D
(http://twostrokemotocross.com/wp-content/uploads/2009/04/img_6630.jpg)
To clarify, the bike was a "home grown" CR500 conversion. From eye-witness accounts the weld separated at the front "Y" part of the frame. This caused extreme stress on the rest of the frame and after a big jump, racer Scott Elderfield found that his bike was two instead of one!
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Now that could make for a really bad day! :o
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well at least engine maintenance will be easier than ever ::)
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Total NZ - for your viewing pleasure!! ;D
(http://twostrokemotocross.com/wp-content/uploads/2009/04/img_6630.jpg)
To clarify, the bike was a "home grown" CR500 conversion. From eye-witness accounts the weld separated at the front "Y" part of the frame. This caused extreme stress on the rest of the frame and after a big jump, racer Scott Elderfield found that his bike was two instead of one!
Ouch, that could've been nasty.
Well now i've seen a broken ally frame for sure.
There doesn't seem to be much damage to the bike, did he feel it start to go and pullover i wonder.
She would've been a sweet ride before that little mishap.
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Scott hit a jump, a pretty high one at that and when he landed, the bike broke in half. He was very lucky not to have gotten hurt!!
He is a video from the ride day....
http://video.mpora.com/p/fLVzVVGqV (http://video.mpora.com/p/fLVzVVGqV)
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I think that bike is from this video!
500 2 Stroke day at Apex 10/04/09 (http://www.youtube.com/watch?v=3TpKN3I6Y-Q#ws)
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Yeah, I recognized it, too. Also notice that video contains the #2 Maico, which I seem to be noticing all over the place these days.
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In the video if you look closely you'll actually see two Maico's, #2 which is Keith Ree on a 500 MX and #74 Neil Berry on a 320 MX.
I really enjoyed that video.....
Braapppp!
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Here's another that is more typical.
http://www.thumpertalk.com/forum/showthread.php?t=576795&highlight=aluminum+weight (http://www.thumpertalk.com/forum/showthread.php?t=576795&highlight=aluminum+weight)
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WHat up with the guy on the suzuki?
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The guy with the Suzuki did something a little different....
(http://twostrokemotocross.com/wp-content/uploads/2009/04/suzuki_cr500.jpg)
He stuck a Honda CR500 motor in his Suzuki Frame....
There's a bunch more photos from that practice day here;
http://twostrokemotocross.com/2009/04/500cc-two-stroke-day-at-apex-motocross/ (http://twostrokemotocross.com/2009/04/500cc-two-stroke-day-at-apex-motocross/)
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i was on a ktm 500 that day did 5 laps then a wire came off the coil ,So i went back to pits put the wire back on (had to take the tank off) went to kick her ,she kicked me back and broke the kick start shaft game over,had a good day though. ;D
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I read somewhere that one of the main reasons why the Japanese manufacturers started using aluminum frames is because of a shortage of quality steel in the Asian countries? Whether this is true or not I'm not 100% sure however I did read that either somewhere on the net or in a motrcycle mag.As soon as I recall where I read that info I'll put it on this site asap.
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You probably read that in one of MadScientist's articles right here on TSM. That's where I read it.