Well. It makes no noise for the first 2 minutes, than gradually starts. I found that the noise changes tones when I shift out to 1st and back into neutral. The engine is strong! Ive read on some other forums about the clutch bearing going out and sounding like a knock. Next I guess I will remove the cover and inspect it. I will let you know what I see. I know the history of the quad and its never been rode hard, but it has sat for 2 years so I bought it with the intention of working out a few bugs. Im not ready to hear that it needs a crankshaft yet tho