82 GS 850G Stumped on engine noise

[Anonymous]

I bought an 82 GS 850G 3 months ago in very good condition with 24 K miles on it and am having trouble diagnosing an engine noise. It occurres between 2500 and 3500 RPM only, and is a slight knocking sound and appears only when I'm very slightly accelerating. Its not a deep engine knock, more higher pitched like a flutter/ between a knock/tapping noise. The bike runs great other than this noise. I'm wanting to get to the bottom of this so I can take it on long trips. Recently valves were adjusted, carbs adjusted and sychronised, all fluids changed, tuned, adjusted timing chain. Its seems to have something to do with tolerances, meaning when I'm only slightly throttling at the rpm's mentioned above thats when its heard, ie., a little too much tolerance somewhere which creates the noise. It doesn't do it for the first couple of miles of riding when its not so hot.
I hope these are enough clues and would really appreciate any ideas you might have.

[Anonymous]

Could it be pinging?
I was also thinking it might be somthing being a touch off or loose when at a certain temp and the vibrations are just right for that rpm range.
To be honest, the GS is known for some engine noise. It doesn't sound too concerning to me.
Mine can make some funny sounds too, but I attribute it to the nutorious GS time chain sound and to exhaust vibration at certain RPMs. I have checked both of these out many times and they are both ok, so I ride through it.

[earlfor]

Re: 82 GS 850G Stumped on engine noise

I think the problem is present at higher rpm's but you just cant hear it going down the road due to road/wind noise. I know you said your valves were recently adjusted......HOWEVER :-) :-) 10 to 1 you have a couple that are too loose. It only take one valve out by 2 thousands beyond range and you would be shocked to hear how much noise it will make. heh heh I just adjusted the valves on my 1150 and the worst one was only 1 thou beyond max spec. I could hear it from 50 feet away. LOL
Adjust the valves....carefully. vewwwey carefully. Be sure the engine has sat overnight and is stone cold when you do the adjustment.

Earl

I bought an 82 GS 850G 3 months ago in very good condition with 24 K miles on it and am having trouble diagnosing an engine noise. It occurres between 2500 and 3500 RPM only, and is a slight knocking sound and appears only when I'm very slightly accelerating. Its not a deep engine knock, more higher pitched like a flutter/ between a knock/tapping noise. The bike runs great other than this noise. I'm wanting to get to the bottom of this so I can take it on long trips. Recently valves were adjusted, carbs adjusted and sychronised, all fluids changed, tuned, adjusted timing chain. Its seems to have something to do with tolerances, meaning when I'm only slightly throttling at the rpm's mentioned above thats when its heard, ie., a little too much tolerance somewhere which creates the noise. It doesn't do it for the first couple of miles of riding when its not so hot.
I hope these are enough clues and would really appreciate any ideas you might have.

[Anonymous]

Adjust the valves....carefully. vewwwey carefully.

Good advice from the Waskally Wabbit!

[Planecrazy]

Here's another interesting possibility ... Although I doubt this is your problem, check the chain guard and see if it is either not properly mounted or whether the mounting tab has broken. My buddy has been riding my 550L all summer, and reported a strange knocking noise that was really worrying him. When I took a close look at the bike while he revved it through the rpm range, I discovered that the lower mounting tab for the chain guard had broken off the frame and needs to be re-welded. The moment I stabilized the guard and stopped it from vibrating against other components, noise vanished.

By the way, it had also slid off of the other tab, which on this particular bike it is simply press fit on to before bolting it down on the tab that broke.

Regards,
Steve

8)

[bwringer]

What is this "chain" you speak of? Is that some sort of primitive system for turning the back wheel? Sounds really greasy and dangerous... :twisted: :twisted:

The point stands about looking all over the bike for other loose odds and ends. Exhaust heat shields and such like to work loose and rattle sometimes.