Im not sure what I have an 82 or an 83 im woundering if the motors are the same and if not what the differece is? I have a motor out of an 83 and i have a motor that came with the bike. thanks

 

The easy way to tell the difference between the 82 and an 83 is easy. If it has the stock steel tank, the 83 has bolt on "air scoops" on the tank where the 82 does not. The 83 has a taller/narower tire than the rear and the 83 has a pro-link rear suspension where the 82 does not. The engines I believe are the same, so you should be able to swap them out. Just make sure the pivot bolt for the swingarm is the same through the engine case.

 

Sorry im kinda new... i have a '01 400ex but i never messed around building anything this 250r was given to me what is an "air scoop" thx

 

plastic things on front of tank to direct air towards motor.

 

Yeah, what he said. Simply though, if the rear shock directly mounts to the swingarm intead of to a linkage like your ex then you would have a 1982 250r.
P.S. We've all been new at some point, some people may crack on your questions.....just ignore it. Most will help you out.
BTW, check out my 2 400ex's that TBR Products just re-did in my pics area. If you need anything for your ex in the future they can hook you up. They are also in the preferred vendor section of the Forums.[img]i/expressions/face-icon-small-happy.gif[/img]