I have 98 king quad. It has difficultly staying running. When I crank it over it makes two different distinct sounds. One sound is it turning over very fast (and will not start). While cranking over, some times it will change from turning over fast to turning over slow and then will start. When running, it seems to make top end noise. I took a compresion test and while it appears to turn over fast, I have very low compresion. When it slows down, the compression reads about 120. I'm hopping some one can tell me what the problem might be.

 

the automatic decompression actuator in the head is probably going bad. Most electic start engines have this built into them. I know the ole z has one. keeps the starter from having to work hard to start the engine.

 

IT does have a decompression valve but it is manual. I think it is just used to pull start it. I'm pretty shure it doesn't decompress automaticly.

 

i wasnt exactly sure what kind was on your model. It could be going bad also, opening when it shouldnt. Just a thought.

 

Check the intake valve clearance. These motors are famous for the intake valve tightening up. The compression will drop dramaticly when that happens.