I have a rolling chassis that I have totally redone but the LT250 engine is in pieces in a bucket, half of the parts are probably not there! Anyway, I want to stuff another engine in this frame, what do you suggest? I have been told LT500, Yamaha RD400, or even 350X engines. Will these fit O.K. with some mods? What other engines would be good, I saw a 1983 YZ490 in the local paper for $500, it said the engine was strong, I would go through it just in case, I don't know much about that engine though, will it work?

Thanks for any suggestions, comments, etc..!!

 

I think any engine you want to put in anything will work with the right modifications. I know of a guy that has a GS1100 motor in his Quadracer 250. The motor is huge and puts the bikes weight over 500 pounds, not good for jumping but the thing will ROLL!!! The only problem I see with the YZ490 engine is that it is air-cooled, and a guy I worked with was just telling me about the one he owned the other day. He said that the maintanance on the thing was crazy. His buddy owned a Yamaha dealer and he said that was were they made their money from, with the parts. That's just one person, but it is still air-cooled. Personally, I have a 86 lt250r and am in the process of putting the motor together this weekend, and I'm giving it one more shot at life. If it doesn't live up I'm looking for a 96 or up GSXR-750 engine to stuff in her. I own the motorcycle and I love the motor. later.

 

I have an 88 Lt250r and have seen several conversions. I have seen the LT500 engine several times and a really nice Ninja 650 up in Oregon. they even used Green plastic. I think an xr engine would be a nice conversion, depending on heigth of the motor. if you do a Lt500 engine you have to use the lt500 harness and cdi box as it is different than the 250. They are also expensive engines to buy around 750 to 1000

1988 LT250R
2000 TRX400EX

 

do not use 2-stroke motorycle engine in quad. they are not balanced and vibrate very bad. any 4-stroke you can stick in there will probably be ok. just make sure engine is low enough in frame for counter shaft sprocket to be in correct location as this can cause suspension binding under power. good luck

 

There's a question I have about the motorcycle 2 strokes. I can't see a big problem with actually balancing the crank, rod, piston, magneto and anything else attached to the crank. This would eliminate the need for a counterbalancer altogether. I know it can be done, just look at a modified engine for a car. Some are internally balanced and some are external. Internally balancing the assembly would greatly reduce any vibration, and I'm sure any reputable machine shop could do this. Has anyone here ever done it or know someone who has. I sure would like to know. Later