i have a yamaha moto 4 that has no compresion i checked and the rings and cylinder are in great shape if it is 180 degrees out will that cause this problem or can anyone tell me what would cause this i had a sticky valve but i cleaned it and its working good
180 out of time will not do that, a bent or sticking valve will, or the timing not set right will also..
when you say that you have compression, by what means have you measured it. second is there a possibility that you may have washed the rings down. if that is the case, take some spray lube,trans fluid and or oil and put a smal amount into the spark plug hole, rotate the engine a few times and see if there is any improvement.
Did you replace the rings recently? Is that why you said it has good rings? If you did and didn't bore it over and put in a new piston you may have broken a ring gland or ring. Time to pull the head. -Mark