Rattle noise at 4700 RPM

[skm599]

Hi there,

I have a 1981 GS550T that has recently started making rattling noises coming from the engine area. It occurs when I have the bike around 4700 RPMs. The bike vibrates at this particular point and I can clearly hear the rattle. However once I increase the RPMs to 5000 the sounds goes away. It also is not present below 4700 RPM. This happens in neutral or while riding. It also does not matter if I am accelerating or slowing down. Usually when it passes through 47000 RPMs I will hear a little rattle for a second. Occasionally I won't hear anything and the bike will be quiet. However that seems to be becoming more rare. I checked for loose covers and screws and tightened everything down. This has not helped with the noise.

THe bike shows no noticable decline in performance. Actually it runs great. Could this be a valve issue? I did quite a bit of searching and found references in the forum to valve clearance issues but no one as mentioned their noise being dependent on RPMs. So I thought I would ask. Am I endanger of damaging the bike by continuing to ride it? I'd appreciate any info anyone has.
Thanks!

skm599

[Nessism]

You might want to check your cam chain tensioner. If it's not working properly you may have extra slack in the chain which is hitting a resonant frequence at 4700 rpm thus the noise.

[Dave8338]

have you looked into the cam chain tension?

[Dave8338]

have you looked into the cam chain tension?

Sorry nessism; got distracted befor the post...

[bwringer]

Hey, has anyone mentioned checking the cam chain?

I'd be more inclined to think there might be loose baffles in the exhaust somewhere. You can also get some interesting noises if one of the engine mount bolts is a little loose.

[skm599]

Thanks for all the responses! I'll check the cam tensions and report my results.