Do you happen to knwo the price or where to find the on the website, because theer is way to much stuff on that website.

 

http://www.lsracing.com/atv_quad_par...RF+450+CHASSIS

$2380.

250R geometry frame with mounts or special pieces for either motor. You will need to have an exhaust system made also. If you think a YZ426/450 or CRF450 motors don't require maintenance, you've got another think coming to you. If you fail to properly maintain these engines you will have a HUGE bill on your hands, especially with the 426 because the parts are quite a bit more expensive than the CRF. The top end will need to be done more frequently on the 2-smoke, but it is a simpler procedure. I'd buy a 250R someone already put the suspension money into for you, because all of the good stuff is rebuildable/revalvable, and put a 265 power vavle cylinder in it. This way you can put it all together and not have nightmare/custom fab machine that you can actually sell when you're done with it/need money. Oh, don't forget the CRF450 is not a legal motor for racing, so you'll have to have it worked over just to qualify for a race as things stand right now.

Good luck.

 

I knwo very well they still require maitenance, my neighbor has one, still in the dirtbike of course and we rebuild the top end about every 50 hours. Thanks, but my biggest question is, can a stock 400EX frame be made to hold the YZF or CRF and what kind of fabbing is required for the radiator?

 

yeah my buddy mx's and has a 250R and he is ordering the powervavle cylinder. I dont know what size but it is supposed to put over 70hp to the rear wheels. And for 500 dollars more he could of ordered one that puts 85 RWHP. I like to see the fourstrokers do that without turbo or nos.

 

I would be a little skeptical of those HP numbers unless the thing is ported for drag racing with a drag pipe and head mods to utulize race fuel or alcohol. I have a 350 powervavle on my ATC and it is supposed to put out 60-65 RWHP. I know more can be had, but reliability is the issue here and no stroker crank. I'll post the numbers on here as soon as it is dyno'd

 

he has the crank already. and yes it is ported and all that. head work I dont know what is done. I think he is getting a cool head or something.