I had a yfz450 in a tzr250 chassis. All in all, I was pretty underwhelmed by the bike. I had fun, but the fabrication is key, and lots of tinkering. It seemed if I always had something to do to the bike. Eventually sold it. Just like a boat, the best two days are the day you buy it and the day you sell it.
With my Yamaha 450 Motard, it's the opposite. Zero tinkering, just gas and go. The last race at Barber, there was another Yamaha 450 Motard on the grid, Jamie Thompson. His is the same year as mine, 2003, same Bridgestone slicks, and was running really good. Would a hybrid 450/125 have faster lap times? Probably at most tracks, but is it worth the hassle? I guess it comes down to if you get enjoyment out of building/tinkering. If so, the hybrid is the way to go. Me? I hate working on the damn things, so it's Motard for me.
I dont think there is a lot of time to be gained on short, tight tracks, but up here at BIR, I think the aerodynamics of a SS would be very beneficial to the top speed. I was contemplating turning mine into one a few years ago, till I parted it out.
I thought I should let you in on some of the info I have I this subject GPtech conversion: YZ450 eng, oem yz450 chassis, R6 forks, short ohlins shock - basic dirtbike conversion around $4k (depending how many new and improved parts you use) - corners very well and plenty of data since 08 - light headwork and can run with SV's - simple conversion/job - very low maintenance, very low cost , high fun factor Framecrafters: make frames for above powerplant taking the project to the next level - TZ250 geometry with a smaller package than TZ frame Rear wheels: 5.0 works well on both chassis, a 4.5 could be even better (less rotating mass, etc) And now we are testing/unveiling then racing (starting this weekend) : Moto 3 bike GPtech - Yamaha YZ250F engine, Framecrafter chassis, RSC products, Galespeed wheels, Graves tuning Fully adjustable subframe, pegs, bar angle - competitive price to moriwaki250 - similar in size but more adjustable fit We are using the YZ to prototype the chassis then we are using the WR250 electric start, 6 speed, fuel inj engine for the production bikes. Bikes are available completely built or in kit form. All parts will be easy to buy from suppliers.
Very similar - weight and where it is, size, etc - the corner speeds are through the roof our Moto 3 WR250 is somehwere in between 450 and mor250 seating size I heard of at east one moto 3 (gp spec) Italian manf is coming to US. FTR is making a moto 3 (gp spec) bike too. These are far more expensive and tuned much higher.
Yup - been on a supermoto. Where do you think I got my engine? I went with the hybrid project as a result of my supermoto experience. Again, where are you getting that the 125 rear tire is insufficient for the hybrid? You only speak from heresay. Have you ridden a 450/125 hybrid? Can all those silly Europeans be wrong? Can all those who have build hybrids stateside be wrong? The torque is not limited by the tire. The technological limit is the stock cush drive on the 125. You're also not comparing apples to apples here. A supermoto on a big track with standard suspension will of course outride the tire. The extra levering force of that tire on the suspension will cause it to do funny things. But needing a 165 and being at the limit?... Only if you're a point a squirt rider with a heavy wrist. What about a 600? Get heavy wristed with that and you'll have problems exiting corners also. Does that mean it needs a bigger rear tire? What about motogp? Clearly those machines make tons of torque but do they need bigger rear tires? Now back to the 450/125 hybrid. It's essentially a 125. You ride it like a 125. When is a 125 ever ridden in point and squirt fashion? Only when you want to go slow. Same case with the hybrid. The gearing alone (I'm at 16/33) limits exit drive. It's meant to be ridden like a 125 with the benefit of low end power. As for corner exit - the bus stop here at Pacific is the slowest corner on the track. I have no problems exiting. When I hamfist it, the front wheel comes up. No problem with grip there. What stop and go type track are you talking about? A go kart track? I'm not going to tell you you're wrong based on your perceptions. I will tell you that a lot...and I mean a lot...of people have done this conversion (more in Europe than here) and have been extremely successful racing the things. The limiting factor is not the tire width. If that were the case, someone in Europe would be fitting wider tires but that simply isn't the case. Believe what you want about tire width. I can't convince you otherwise. Only thing I can do is point out that tons of people including me have done it without problems. Only if your SS races against a 450/125 hybrid. Based on aerodynamics alone a 450/125 hybrid will go faster. As for the hassle. It's a disease. Tinkering.
If you don't have one, or haven't built one or don't race one please dont give advice about one. These super single/hybrid threads get really deep in bullshit. If you need someone to convince you to get one then don't waste your time and money. If you're gonna do it you'll just do it.
I have to agree: supersingle threads are usually filled with people with no experience with these bikes and either giving advise or bringing up topics that dont even matter in the build. Just ask companies and individuals that are familiar with the bikes - you will get honest answers. I have actually had a suspension company tell me what i built would not work (after a season of racing and winning), unless someone has hands on experience with these bikes dont even listen to them
one of these days, Geoff (and it could be a couple of years before money and time align) i'm going to be enlisting your services to build a super single. i want to race one so bad...
Who are you guys using for rear sprockets? I went with Rebel Gears aluminum and even after just one trackday, the teeth are bending over. I'm sure my cheap chain doesn't help but custom sprockets are getting expensive.
I will offer rides to anyone interested (with valid skills ) - i have been meaning to set something up formal, but i need more bikes, structure, etc. This is just the ticket to push me to offer the following: If you want to test or ride one- call gptech and we will set a time and place easiest for both parties. If i dont travel any further than mi tracks i can offer this for the cost of entry (whatever org at track at same time), gas in bike and some cash to cover normal wear (approx $100), and cover any crash damage. If i have to travel to a track then there is additional costs. Fly in and test for yourself. Anyone doing a complete build will get dealer cost on all parts. Buy as you build is ok too. Thanks for the confidence, if you do buy a kit - i guarantee you will enjoy or i will buy the complete bike back.
geoff - are you going to be at barber next weekend for the ahrma event? i'm going to be racing the evil dr. hate mcdeed's yamaha supersingle. friday practice will be my first time on it. hope to see you down there.
Andrew Weiss raced a super single in clubman in 2001-2002 IIRC. He used a Yamaha Raptor 660 engine in a TZR250 frame. Not only was Andrew a good rider, his bike was FAST. I think his bike was built by Tim Barker. I'm not sure if they do this sort of thing anymore, but I remember that thing being badass. I'd love to see a superbike thumper with a big bore KTM thumper in it. I'll bet the vibration would be pretty insane-o.
I would give my advise on what sprockets I use on my 450 that had done dozens and dozens of races on the same sprocket with little wear, but since I havent done the hybrid thing, I will keep my mouth shut.
No barber - i am going to putnam with usgpru with new 250 moto 3 bike same weekend (framecrafters is also coming with me) With enough time someone could reserve our 450 as a rent a racer (you are somewhat dependent on my schedule) I see more and more 450s at races over the years. Once people figure they are next to nothing to maintain and crash then you might see more. All about the cornerspeed and braking.
Yes, Andrew's bike was fast! I think it was actually a Yamaha SZR660 punched out to 780cc with ram air, if I remember correctly. Oh yeah, I beat that bike at the 2004 GNF on... my Motard.
