yzf to yz convert

[jacko748]

Hi guys,
New to this but my yzf 250 has demolished engine clutch gearbox and a couple of casings left. Thats it!!!!
Could anyone tell me if I could convert it to a yz 250 if I could get a motor for a fraction of the cost of a rebuild? My dilema is , if I buy a yzf motor there is a chance it may happen again if I dont get it serviced straight away.

 

[rmc_olderthandirt]

To start with there shouldn't be anything specific to it being a four stroke that is causing clutch and/or gearbox problems. If you managed to get a bad unit then replacing with another four stroke should be reliable. If the problem is related to something you are doing to it then I would expect a two stroke engine to suffer the same demise.

If you insist on changing to a two stroke then I suspect that you would be a lot better off selling the existing bike or "parting it out" and buy another bike. To swap you are going to need a complete motor and transmission, pipe, silencer. I would not expect the carburetor to be in the exact same spot and angle so you would have to make a new "boot" between the carb and airbox. If the throttle cable isn't compatible you may need to have a custom throttle cable made.

The four stroke pipe is fairly skinny compared to the expansion chamber of a two stroke so it might interfere with the frame. I really doubt that the mounts for the pipe and silencer would be in the right spots so you will need to do some welding on your frame. Radiators might not match up so you may have to buy the two stroke versions and then weld on the frame to mount them. You might need new plastics to cover the two stroke silencer.

When you were all done you would have a one off bike that has no advantages over a real YZ-250 and could be a real pain when you needed to replace a part.

Rod

 

[jacko748]

Cheers Rod,
It used to be that the sentance 2 stoke drove fear into the heart of us 'Yorkshire men' now its 4 stroke! Being tight as a ducks ass we don't like tospend money, I think it's back to the screamers.
Jay.