86 GS850G top end tapping - any advice please?

[ChazNZ]

I've recently bought my GS850G - a bike I've always wanted! This one has done 115,000km (just over 70,000 miles) and seems in generally fairly good shape. Original apart from the exhaust and nothing obviously butchered. It starts readily, doesn't smoke and pulls well.

But... At tickover there is a fairly loud tap from (I think) the top end. Video here: https://youtu.be/jAylFk5hcac Once you get rolling the noise is no longer apparent.

I don't really want to go in there just yet - I want to ride it for the Summer (through until May here in New Zealand). However, if I could eliminate the noise by (say) servicing the cam-chain tensioner or doing the tappets, then I will. And if I'm likely to cause further engine damage by leaving it, than I guess I had better do something.

Is this a familiar noise to anyone? Any suggested further diagnosis I can do?

Much appreciated!

 

[ged]

Nothing to worry about. Its called camshaft end float or cam walk. Horizontal movement of the camshaft causing ticking or tapping noise during idle or low revs. Goes away when revs increase. Have a look at BikeCliff's Website http://gsarchive.bwringer.com/ There is a great read me article about it called CAMSHAFT ENDFLOAT MOD. Cheers

 

[ChazNZ]

Thanks so much, that's very reassuring! In the article it mentions that the tap doesn't happen when you start from cold, which is also true for mine. So that pretty much confirms it for me.

So I'll just relax and keep riding it. Summer is just about here so can't wait to get out there.

Here's a pic of the GS

 

[ged]

Welcome to the forum ChazNZ and you have a nice bike. Cheers.

 

[cowboyup3371]

With that said, you should still check and adjust your tappets as part of regular maintenance unless you have documented proof they were recently done

 

[Steve]

It may be cam walk, but it's more persistent and regular than any I have heard. Cam walk usually comes and goes at idle, then disappears at about 2000 RPM. Yours seems to be a regular knocking. You said it goes away at higher revs, but I still heard it in the video. Yes, it's masked a bit by other noises, but it's still there. I would definitely check valve clearances, but also be sure to torque the cam holders first.

.

 

[ChazNZ]

It may be cam walk, but it's more persistent and regular than any I have heard. Cam walk usually comes and goes at idle, then disappears at about 2000 RPM. Yours seems to be a regular knocking. You said it goes away at higher revs, but I still heard it in the video. Yes, it's masked a bit by other noises, but it's still there. I would definitely check valve clearances, but also be sure to torque the cam holders first.

.

That's interesting, thanks. This video was recorded before the engine was warmed up - it does improve. I'll definitely do as you say though.

 

[hampshirehog]

Agree with Steve - that doesn't sound like cam walk to me. I'd pull the cam cover, check the valve clearances plus cam chain tension and look for loose cam bucket as well. If you lean the bike on one side does the noise go away?

 

[Chris P]

Agree with Steve - that doesn't sound like cam walk to me. I'd pull the cam cover, check the valve clearances plus cam chain tension and look for loose cam bucket as well. If you lean the bike on one side does the noise go away?

I have a 79 GS550L that has that problem and it goes away when it leans to the right. What does it mean?

 

[Boriqua]

I am going to go out on a limb here and say .. old technology makes noise. I get a rattle when I first start the bike that goes away once its warmed up .. about 2 miles out..
After that my bike definitely has a sewing machine sound to it. I actually find it quite pleasing. My VTX 1800 while a stalwart beast was soulless.


I want to check the cam chain tensioner and possibly rebuild come the hot weather but I bought a brand new Triumph bonneville in the last year they did carbureted so I think it was around 2003 but I cant swear. It ticked and tingled from the day I bought it to the day I sold it. It literally sounded like my grandmothers sewing machine. I kind of figured so long as it was good consistent tick .. it was fine.

You shouldn't ignore all noises but you should keep in mind you are on 30yrs+ technology and have the engine and all its idiosyncrasies directly underneath you between your legs.