I have access to a new 400EX frame without a motor. Can and how easy would it be to bolt a motor from a CR250 into it?

 

You would need to change the motor mounts which shouldn't be too bad. The one thing that is a concern is that a CR250 engine does not have a counter balancer and will vibrate really bad.. I spoke with someone who had a custom Lonestar or Laegers frame with custom ply mounts built for a CR500 engine and the person said they can only ride it for short periods of time before it vibrates them too much....

Just my .02cents! [img]i/expressions/face-icon-small-smile.gif[/img]

 

How much would a used or new frame for a 300ex or 400ex cost?

 

I have seen frame go for anywhere from $200 to $800+ on the net.

 

I can have a new 2002 400EX frame and all the goodies... Only missing the engine. Any other ideas on what motor to squeeze in to it? I can get the whole thing for $2400 less the motor. Zero miles!

 

I heard the ATC250R motor is a great motor to put in a quad. It is supposed to be better than the TRX250R motor from what I hear. Good luck!!

 

Hmmm.. Engines from: 250R, 350X, another 400ex engine.... Hell if you are creative and mechanical you can put just about anything in there, it is just with the bike motors, they dont have counter balancers... They thing that gets me is, if they dont have a balancer, why dont they vibe the hell out of you?

 

One thing that you might worry about running a CR250 motor would be that the gears in the tranny arent as strong as the ATV trannys, thought I would throw that in.

 

I would look for an XR600 motor, they're counterbalanced and shouldn't be to difficult to install. That should be plenty of power for that frame.

 

It's not worth it, If you drop a CR250 engine into a 400ex all you have is a trx250r with a lot of vibration, weaker gears and misfitting parts like the radiator. It will probably be much cheaper and reliable to just find an R in good condition, about $3500 total. Now a cr500 engine or a 600xr engine, now that's a project.