Engine Transplant?

[DESDAK4]

I am asking this question for a friend. He is woundering how long they have been making some the dirt bikes you guys are useing the engines out of to put in your quads and which engine is really the best to do this with. He will be wanting to do this project based on either a 250r or 400ex frame. He just needs ideas for motors and how far he can go back in years to start looking as this will be somewhat of a budget build.

Thanks for all your help in advance.

Jay
USAF

[d-14 rider 27]

usually we go with the 400-500 range, yamaha started building the yz400f in 98 i believe which is similar to the 426. honda started the crf 450 in 02 these are new yet, there are motors on ebay once in a while. remember, you can get damn near half your money back by parting it out. i havent done a yamaha conversion yet, but other than the oil rezzy it looks like it fits in a 400ex frame a helluva lot easier than the 450. i built a 450 tho cuz i like honda, and i have a hard time kickin a yamaha with a bad hip (at 19 years old :eek: ) but anyways, you can always go with a bigger bore machine like a xr600.