My buddies 02 raptor(Yoshi pipe) would not start for him until he flooded it out. Then it would start to pop and fire a little, eventually it would run. It also did not want to idle down for him.

After rejeting a couple of times we decided to check the valve adjustmend. All 3 intake valves were way to tight, no free play at all, and 1 exhaust valve was loose. After adjustment it starts right up and runs great. The best it has ran since new.

He had them checked/adjusted by the local shop a couple of months after buying it. So it seems that it should be done 1 or 2 times a year.

 

Yes that is correct. Mine did the same exact thing and the valves where the last thing I checked as well.

 

Thanks a lot witti! Thats good to know. Thats the last thing I would have checked if I was having those problems too.

 

Valves out of adjustment are also the root cause (IMO) of the "backfire and boot-coming-off" problem.