OzVMX Forum
Clubroom => General Discussion => Topic started by: vmx42 on November 01, 2012, 08:18:24 am
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Hey Guys,
Don't you wish that the factories would make something like this...
(http://i154.photobucket.com/albums/s255/vmx42/PA230008_145025.jpg)
(http://i154.photobucket.com/albums/s255/vmx42/PA230002_376349.jpg)
(http://i154.photobucket.com/albums/s255/vmx42/carbon_silencer_475229.jpg)
(http://i154.photobucket.com/albums/s255/vmx42/engine_cradle_351917.jpg)
"I just wanted to share this amazing project with all of the two stroke fans out there. We just finished this factory level 2 stroke build after a year and a half of R&D, testing, changes, etc. The end result is amazing and we ended up with a 53hp rocketship that weighs 15 lbs less than the AMA minimum weight limit for that class! 201 lbs, ready to ride with an empty tank. We used a Varner Motorsports modified KTM 250 sx powerplant in a 2011 Honda 450 frame with production based Showa suspension including a SFF Showa fork, modified, valved and set up by MB1 Suspension. The entire engine cradle and billet engine mounts are hand fabricated and machined to accommodate the KTM powerplant. Racetech Titanium was instrumental in helping bring the weight down with all of their titanium fasteners, axles, brake piston and pivot hardware. The bike also utilizes many one-off titanium or alloy parts and heavily modified OEM parts as well. DLC coatings were utilized in many critical areas including the shock shaft, brake hardware and pins, brake pistons, select transmission parts, titanium linkage pivot bushings, and swingarm pivot bolt to name a few. It took over 500 hours of trial and error, testing, changes, extensive mods and many hours of scratching our heads to get it perfect but I feel this is the most refined 2 stroke conversion build anyone has ever done. "
You can follow the build at: http://twostrokemotocross.com/forum/general-two-stroke-talk/crfktm-250sx-hyrbrid-drool-worthy/
VMX42
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Works for me :)
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And me. 8)
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Cool, but what does it achieve above and beyond fitting a linkaged KTM250SX with lots of titanium bits?
???
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It won't suffer from head shake.... :D
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Cool, but what does it achieve above and beyond fitting a linkaged KTM250SX with lots of titanium bits?
???
I would have thought by now that you would have understood that logic has no place on this forum!!!
The guy who constructed it did actually answer that question... from his measurements, the Honda based bike is 5lbs lighter than the equivalent KTM. Beyond that I think it was his dream bike and he is proud of the results...
I reckon its great and a terrific alternative to the wave of 4-strokes in the marketplace. It just shows what the Japanese could produce if they put their minds to it. Afterall they are all complaining about new bike sales being down, but all they do is recycle last years 4-stroke with minor evolutionary updates. If one of them was brave enough to lobby the rule makers and produce up-to-date 2-strokes they might just surprise themselves with the market response.
And if they don't I for one will continue to celebrate somebody doing their work for them!!!
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Seems like a lot of work for 5lb, especially when you end up with a shitty aluminium frame...
Look at Yamaha - they haven't touched their 2T YZs in EIGHT years now (god-awful 2013 plastics aside), and yet the bikes are still just as competitive against their opposition (both 2- and 4-stroke) as they were back in 2006. *shrugs*
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Seems like a lot of work for 5lb, especially when you end up with a shitty aluminium frame...
Look at Yamaha - they haven't touched their 2T YZs in EIGHT years now (god-awful 2013 plastics aside), and yet the bikes are still just as competitive against their opposition (both 2- and 4-stroke) as they were back in 2006. *shrugs*
I will pass your details onto him and next time he wants to construct his dream bike he can give you a call for permission... :o
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If I was going to go to that much trouble I would have chosen a KTM 380 engine
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Great bike, I for one would line up for a new honda 2 stroke if they seen the light. The most modern bike in my shed is a 98 WR250 2 stroke, its such a fun bike to ride. After all his time and effort, I hope he wares it out with a grin from ear to ear.
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As the self appointed chief batton twirler for the hot rod dirt bike movement, this bike rings my bells. Who cares about the logic of it, it's one mans concept of the perfect dirt bike and I respect his right to build it.
The cookie cutter sameness of the modern dirt bike design bores me shitless, this bike gives me hope that the good old hot rod, DIY mentality still exists out there in McMansion suburbia.
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MMMM 490 Yam in a modern frame that sounds like a good idea . But I love this bike looks like a shxx load of dollars have gone into it .
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I think it's a thing of beauty but I don't like aluminium frames!
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Hybrid = good shit
best of both worlds ;)
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Honda parts prices and ?
I'm not trying to be negative, but I just want someone to explain why this is "better" than a 250SX with titanium bits?
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I'm with Nathan, why a KTM ? Good on him though.
Much prefer YZF frame/ yz 250 conversion fitted with Ohlins 360 kit :P
(http://i118.photobucket.com/albums/o82/evo550/KGrHqJHJBUE63VVHdSPBOy7o6m6iQ_62.jpg)
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I'm not trying to be negative, but I just want someone to explain why this is "better" than a 250SX with titanium bits?
It's really got nothing to do with better. It's just one mans concept of the perfect motocross bike, nothing more, nothing less. While I'm here sticking up for the bloke and his bike, I myself wouldn't have built it his way but that's what these projects are about....we all have a different perspective on what's 'cool'.
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It's really got nothing to do with better. It's just one mans concept of the perfect motocross bike, nothing more, nothing less. While I'm here sticking up for the bloke and his bike, I myself wouldn't have built it his way but that's what these projects are about....we all have a different perspective on what's 'cool'.
So is that really that hard to understand? Well said Firko...
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I like the concept and associated ingenuity
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It certainly is a sweet creation. I would have liked the 300 engine in it for that added pulling power
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Here is my idea of a two stroke build :)
luv that pipe!
http://blog.derestricted.com/racing/250cc-swm-fantic-2-stroke-dirt-tracker/
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Here is my idea of a two stroke build :)
luv that pipe!
http://blog.derestricted.com/racing/250cc-swm-fantic-2-stroke-dirt-tracker/
Very nice!!! ;)
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Here is my idea of a two stroke build
luv that pipe!
http://blog.derestricted.com/racing/250cc-swm-fantic-2-stroke-dirt-tracker/
Very nice!!!
Damn that's nice..........here's something similar, a C&J cr450f
(http://i1112.photobucket.com/albums/k495/firko2/08Aug06-CJ-Honda4-1.jpg)
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Here is my idea of a two stroke build :)
luv that pipe!
http://blog.derestricted.com/racing/250cc-swm-fantic-2-stroke-dirt-tracker/
Hmm, a special flat track frame with a Gasser motor. I don't see where Fantic and SWM fit into the picture ???
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I'm not trying to be negative, but I just want someone to explain why this is "better" than a 250SX with titanium bits?
It's really got nothing to do with better. It's just one mans concept of the perfect motocross bike, nothing more, nothing less. While I'm here sticking up for the bloke and his bike, I myself wouldn't have built it his way but that's what these projects are about....we all have a different perspective on what's 'cool'.
Sure. But what is it about this bike that floats his/your/Jeff's boats?
Is it simply that it got built despite logic?
I'm not trying to be argumentative or negative, I genuinely don't understand what is to be excited about: The end result doesn't seem to achieve anything particularly useful from either a rider's or an engineer's point of view.
If it makes it's builder happy, then great - but why does it make him happy?
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Nathan,
I just like the bike. I appreciate that it is one guys dream bike and I admire the standard of work he has put into it.
Nothing more than that...
Could he have built a great KTM...? Sure!!! But he didn't so I posted the images of the bike he did build.
As for why to get excited about it... a 201lb, 56hp 250cc Two-stroke sounds like a lot of fun to me [and heaps more fun than a 4-stroke - IMHO].
And as for an engineers point of view... well again he obviously thinks that the KTM is the best engine and the CR the best chassis... so he set to work to produce a combination of the 2 hoping that the synergy would produce a great bike. His execution looks first class... so from an engineers point of view I reckon he has done damn well.
Motocross would be far more interesting if top line racing allowed these kind of one-off specials to compete, the cookie cutter 4-strokes are a bit boring IMHO.
So that is why it floats my boat... I just like it. I didn't sit down and examine the logic behind it, nor did I consider the ultimate performance, or the cost. It's just a MOTORBIKE... and I reckon it looks HORN [to paraphrase Robbie Phillis].
I think that just about covers it... Have I mentioned that I just like it? :D
VMX42
P.S. I also like the Dutch Twin shockers [sorry Firko] and the NZ fuel injected 2-stroke. Not a cookie cutter in sight...
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Firko nailed it.
Personally have not rode an alloy framed smoker that I was happy with - they are just far too harsh and do not feel right. Probably the closest I have tried was an alloy framed YZ250 up in Japan (or was it an OW?) with the next being my highly modified '97 CR250. Some foam in the frame rails, '96 RM250 conventional forks and a few custom bits here & there made it quite tractable.
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Sure. But what is it about this bike that floats his/your/Jeff's boats?
Is it simply that it got built despite logic?
I'm not trying to be argumentative or negative, I genuinely don't understand what is to be excited about: The end result doesn't seem to achieve anything particularly useful from either a rider's or an engineer's point of view.
If it makes it's builder happy, then great - but why does it make him happy?
Nathan, if you have to ask those questions and expect a considered answer it's my guess that you'll never understand the mindset of people who build specials. There is no defined answer to any of your questions and if you asked the builder those same questions he wouldn't be able to answer them either. Building these kind of bikes never fully makes sense to anyone outside of the thought process that creates them but who gives a toss? This and any other special are the end result of one mans dream and whether they're logical or not is totally irrelevent.
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I'm all for specials that make sense: I built my 1986 KX200 because I loved the KDX-C motor, but the rest of the bike was too low and too fat. It was easier/cheaper to build a special, than try to get the KDX roller behaving like a KX.
I'm about to build a 98 KX200 for much the same reasons.
I own a "YZ200WR" which combines the WR200 motor with the weight, ergos and handling of a YZ125 - I didn't build it, but it makes sense because it is now a bike that doesn't exist otherwise, and is ultimately superior to all of its three donor bikes.
A mate is building a re-powered KLX250 Evo race bike - it makes sense, because it's both making a low cost race bike from bits he's got hanging around, and because it should be superior to both donor bikes.
Hybrid bikes like the XL Elsinores, Yamaicos, 500AFs and even those bloody HLs all make sense - the end results are clearly better than (or at least different to) the donor bikes.
While I can appreciate the workmanship in the KTM-CRF, it still strikes me as a pointless exercise - spending a lot of time and money to end up with something that's not appreciably better than either of the donor bikes.
(Yes, his time and money to spend as be sees fit)
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my kx500AF which is a late model 450 frame with 500 donk
is the best balanced bike i have ever ridden and i have been
on a few, been riding her for 5 years now and would never part with it ;D
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Only thing I don't understand is why he didn't start of with a CRF250 chassis instead of the 450... If the idea was to make it as light and nimble as possible.
To all those here who don't like alu frames, how new a bike have you tested? Honda have spendt the last 5 or so generations of aluframes making them less stiff, so you can't compare them to the -97 frame who flexed about as much as a brick.
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08 TM250, 08 CRF450R, 06 YZ125, 07 CR125, 10 KXF250, 09 YZF250 and a couple more I've forgotten about.
The only one that I think is worth piddling on, is the YZ125. ;)
Notice that the Euros who are serious about enduro bikes are sticking with steel - and the way TM's WEC/EWC fortunes took a dive around the time they switched to aluminium...
When I bought my "new" MTB in 2005, I did a lot of research to get one with geometery as close as possible to my old chromoly Diamond Back. Ended up with a [Jim] Felt with an aluminium frame.
What a fugging shitbox!
Where the old one tends to be stiff and harsh at low speed, it all comes together as you get the speed up - the springiness of the chromoly starts working for you and it all starts flowing.
The alumium one starts off feeling dead at low speed, but as you pick the speed up, it feels.... dead.
Same basic story with dirt bikes - while they're better than the old 97 CR250 railway tracks, the newer aluminium-framed bikes lack the feel of a decent chromoly frame. My Husky 150 is the best handling bike I've ridden, despite the suspension not being properly sorted (it's close). The Beta 350/400 is a very close second.