So my little brother has a Yamaha raptor 80 (2005 I believe). It was fine when we got it but in the last couple months it has been an absolute pain to start. To get it going we have to jump it with our other quad, and even then it takes about 30 seconds of the motor turning over to get it going. Once it is warmed up; it starts with the electric start no problem, but once it cools again, we’re back where we started. I have cleaned the carb twice, and also put a new spark plug in but this did nothing. Any ideas to why it does this? Any suggestions will be appreciated thanks.

 

Check compression to see if it at least has over 100 psi. If it shows less that might be the problems area.May be time for a fresh top end.

 

The 80cc Yam engine is well known for this problem, almost always the valve clearance has gone. Adjust the valve clearances first, 0.003" on both valves, then if the fault is still on, check compression and whether choke is working etc.

 

Sounds logical since it's a 4 stroke. I have way too many 2 strokes on the brain..

 

Adjust valves first than check compression. Make sure you have the throttle wide open when you check it. 90% sure valves are your problem.