1998 Suzuki lt80 noisy.

[Jamesjoe22]

Just got this bike for the boy and fires right up and has good power but just seems noisy. Has a pretty decent ticking/almost knocking sound at idle and low rpm. First thought was rod bearing or wrist pin but riding it when you get into the high rpm’s it pretty much goes away. I did notice some oil coming off of one of the exhaust flange bolts. Any experience with a bad exhaust gasket sounding like that? Or could it be the clutch ? Any help would be appreciated !

[Mech]

There are ways to pinpoint the cause of the noise, but it still takes a bit of experience to say how bad it is..

So.. does the noise seem louder hot or cold ? If it's loader cold how long before the noise quietens slightly.. Pistons expand a lot in the first minute as they heat up. If it's worse cold and quietens quickly then piston slap would be the suspect. Bottom ends don't quieten much in that short time but they do get loader as the oils warms and thins.. in ten minutes say.

If you put it into gear and apply a bit of throttle to load things up, does the sound get louder or quieter.. Piston slap and broken rings and valve problems won't get much quieter or louder, but crank play will get louder under a load. 

If it's in neutral and you give the throttle a very little blip to raise the revs a couple of hundred revs, then let it off again.. what does the sound do. Is their a momentary taping sound ? That's a sign of the piston pin being worn. Piston pin wear doesn't get noisy under load but it does as the load comes off the piston and the piston can fly up and down freely with a few revs on.

Temperature making a difference to the sound tells us a lot. Load effecting the sound tells us a lot. Revs with no load on things(just as it reaches revs and then starts to slow) tells us a lot. The combination of these three things helps us pinpoint the problem.

[Mech]

Start it up from cold and listen as it idles, then listen with a very gentle rev within a minute of startup, and then slip it into gear and apply a little load while it's still very cold and listen. Then warm it up for a few minutes but not long enough for the oil to get hot, and do all three tests again. Then warm it right up so the whole thing and the oil's hot and do all three tests. Take notes of all three temps three tests and report back.