its a common thing with some rappys, i think theres a sticky on this if u look aroundHey everyone im John and im a little new to the 4 wheeler scene ive been a dirtbiker since i was 6.. anyway i just got a raptor 660 its got an aftermarket carb(with new jets) and a full yoshi exhaust. My exhaust turns cherry red after about 5-10 min of riding..any thoughts?
You werent detonating! It sounds like ball bearings in a soda can. You will know it if you hear it. Sounds like you have some valve train problems to me. Or a lack of compression issue. JMOMy brother in law and I have had several conversations regarding what gas we should be running in our 660r's. I have explained to him that according to everything I have read about our stock raptors we don't need to run anything better than 87 octane. Well the other day we were out riding and I noticed as the day got hotter and the longer I rode sometimes when I hit the throttle the motor would rev, but it would not make any power. Furthermore, when it revved like this, the sound was much different than it usually is. I paid no attention to it at first then I got to thinking that I must be getting predetonation due to the ambient temperature and the additional heat generated by the motor. He runs 93 and was not having this problem. I was running 87 and I think that predetonation was what was happening. What does this sound like to you guys?