87 yamaha Warrior 350

[dcday133]

I just got a 97 yamaha warrior 350. It ran great when i first got it, but shortly after It lost power and started knocking. The guy I got it from told me he only ran 91-93 octain fuel only, but didn't think it was needed. With that information I put 87 in it, ran it for maybe 4 hours, and it started knocking. Is that the problem, or is it something else? Also the oil level was just above the bottom line on the dipstick, is that a problem? Just looking for any info I can get. Thanks...:confused:

[dcday133]

:cool: So I ask a Gp1 Racing mechanic, a local bike repair shop located in Hemet, CA, and he seggusted it to be the valves. So I came home and removed both valve covers and realized that a nut was missing from one of the adustment screws. I just got this quad, and haven't put many hours on it. Is it possible they knew about the nut missing and just tightened the scew? I would think it probably could last for a while that way. but I'm also worried i lost it in my motor. Whats the risk if that was the case?