I'm really curious about putin a 350X motor in either a 250X or 300EX frame or a 250R frame. About how much would a conversion like this cost and could i use either swing arm? I know with the 250R frame i can expect a cross member to be in the way. How much more does the R frame weigh over the EX's since one is steal and the other is aluminum? I appriciate any info you have, thanks!

Dave

 

Im not sure about the aluminum and steel part. I do know there is serious modification done to a 250r frame. THe 350 engine fit right in with a couple a bushings into the x. Thier is a kit and everyhting. The swingarm are interchangable on the x's. Search the forums. thier was a very large discusion of this early. I am going to go with the 250x conversion since. Ive heard if you have the time and money a 250r conversion is much better in most peoples opinions. Hope this helps

 

A 250R frame would b a little hard to come across, and it deserves a 250R engine in the first place. Stick with the 250X or the 300EX frame.

 

One more quick question.. would i be able to use the EX's air box or would i have to go without?

 

ive also wondered about that. What about mounting the carb and controls and such??

 

Dave here is the search result on a very good converation about the 350X conversion. I did a 89 "R" frame conversion. Very very nice.

clickhere

 

HP500 helped me alot. I ask that question earlier.

 

The only thing you have to modify to make an x to x switch is to move the top rear motor mount on the frame, and extend the headpipes on the motor about 3". everything else bolts right up.