My new to me '92 quadracer makes a small "knocking" noise when you lean your head down by the engine.

Do two strokes tend to make lots of noise? (never owned one before so they are new to me)

Is the bottom end going out?

What does predetonation sound like?

PS It is a lrd ported 265 with a spacer and a yz250 piston (or so I am told by the previous owner). I changed the oil in the case and put new fuel in the thing. It has a trinity stage 4 head so I was told to use race gas (which I did). Rode it for about 3hrs and the noise never got loud but it is noticeable if you lean down to the side by the engine.

Thanks.

 

I believe that noise is the top end. Mine make the same noise. But, still running strong.

 

yah my '87...same thing. Sounds like piston slap so I took off the head and checked and everything's good. Think it's just a quadracer noise, I've heard others talking about it also.

 

Mine makes a rattling kind of noise as it runs too, always has. Im going on 3 years and its never grenaded. I have a feeling that it is the worn clutch basket. The ears had been grooved and likely filed sown before. My plates move back and forth an awful lot (1/8 inch or so) so it could possilby be that.

 

Thanks dudes. I'm new to two strokes and not used to noises, smoke, powerband etc. I do love that power hit on acceleration though...kicks behind on my xr80 that I had in 1984 [img]i/expressions/face-icon-small-smile.gif[/img]

 

My 91 and 86 both had similar noises and never had any problems. I can only hear it at a slow idle above that it goes away. I figure its likely in the clutch or the gears under the clutch cover.