I am currently building a 250r from the ground up. my friend just gave me a really good deal pn a CR250 motor. just wandering if it will bolt up the same and what year swingarm i would have to use? what would be some flaws to using this motor

 

You can use the top end from one that was made in the 80's, but you need to weld up the power valves. I don't if the lower end will bolt in,but it will vibrate so much. It doew not have any counterblancer. If your lower in is still good use it and maybe the top from the CR if it fits.

 

In my opinion, which may be incorrect, the CR250 engine would not vibrate TOO badly in the quad frame. I have seen people with a CR500 motor, which is sure to vibrate more, right?
So if htey can hang on to a 500, why couldnt anyone hang on to the 250?
However, since you are building from the ground up, be sure and use an anti-vibe steering stem, bars, anything anti-vibe you can find. I saw somewhere once some anti-vibe motor mounts which used rubber bushings or something to cut down on vibration, maybe look for something like this as well.
However, the one bad thing about the CR motor is the lack of 6th gear, I guess this depends on who you are, but I really like havin that extra gear on my quad.
Good luck with whatever you decide, I hope someone can shed more light on the subject.

 

thanks for all the help guys, but one one q? what year swingarm will i have to use

 

I would stay with a TRX or ATC 250R motor. It will cause you less problems in the long run. But, if you are gonna go with a dirt bike motor get a CR500, I have saw a few real trick Fourtrax 500R's.

 

In regards to the cr motor, I'll simply say this: Do not use this motor in a quad chassis!
The motor will crack the frame...a reputable builder and good friend of mine even tried nylon motor mounts to counteract the vibes, all to no avail.
The only way to build a quad with the cr motor is to use a stronger 4130 chromoly frame, and even then the vibrations will shake the blood out of your arms even with high dollar anti-vibe everything...just ask Charlie Ohton, who built a trick cr 500-laeger framed drag racer. The bike shakes so violently that the pipe mount broke off after two or three runs up the hill. Yes its fast, but it is unrideable for extended periods of time.

If you want the cr cylinder on the trx lower end check out ftzperformance.com. Or if you want more power than a CR 500, get a hold of Dennis Packard who uses Honda Pilot cylinders on trx bottom ends to achieve up to 450cc and well over 100 hp.

What I'm saying is this, you can achieve all of the benefits of the cr motor without the vibrations by retaining the trx lower end...you've been warned.

sanoduner
phx,az