Seems like engine knock?

[free99]

Hey everyone, kind of a perplexing issue. I know about the dreaded "cam walk", with a fix detailed on bwringer's site, but... For some reason, the last few weeks when I'm getting off the highway (and the engine's good and warm) there's a consistent knocking sound. I think it might be there above idle, but I can clearly hear and mildly feel it at idle.

I've checked color on both cylinders using my colortune, checked carb balance, the carbs were cleaned about a month and a half ago... I'm not sure why it appears the knock has become more pronounced.

There's an occasional misfire when idling, the carbs are stock and as mentioned, tuned and balanced. No change in jetting, etc.

The tips on both spark plugs are this interesting brown color. Is this an indication of something? (Apologies on the weird framing, oily fingers and smooth phone cases are a poor pairing)

 

[free99]

It sounds a little bit like, https://www.youtube.com/watch?v=-kGxLMDATu0 but more consistent. Additionally, I notice the bike generally has trouble idling. The choke helps somewhat, but only marginally. Carbs cleaned ultrasonically, then backwards air pressure was applied. This is after all jets were removed, and the carbs disassembled.

 

[Hokano12]

Sounds like cam walk to me. I’ve had cam walk with valve clearances being too large. Then once I got the clearances into the proper spec, the walk went away. Maybe check your clearances, adjust if it’s out of spec, and keep riding.

 

[Gorminrider]

I hear cam-walk in the video - if you have that cla clonk sound at that slow rythm, that's most likely what you have too. They actually did a recall/mechanic's bulletin on the GS500 but didn't on their earlier bikes......with the valve cover off you can actually push the cam backnforth a little and/or if you lean the bike while running it may go away.
I put some thin brass shims on the left side of cam-ends in my 650 which was much more pronounced than your example. People say it "goes away" above idle rpm but I could hear mine at higher rpm-t'was just masked by faster engine.

 

[free99]

Gorminride, would you say the brass shims helped?

My engine rarely slips into this knock mode, unless I've been hauling ass on one of the local highways, which is more often than not. I generally slow down a mile or two out from my destination to let the engine cool; my point in mentioning this is that the knock seems to appear when she's hot.

If the shims work, any suggestions on design and install? Thanks kindly.

 

[Gorminrider]

I've sold the bike and haven't heard report on how it's doing with the mod. But I think it's worth a try(it surely shut it up the time I ran the mod) if yours sounds anything like the mp3 I made. (link still works-you ca download the mp3 there too.)

https://www.thegsresources.com/_foru...oat-mod-update
Maybe Stainless sheeting would be better than brass. Less likely to wear. My preliminary thought was I didn't want bits of hard metal worn off and running through the engine but I'm not sure that's a real worry because as it is, the cam is banging and spinning on the aluminum clamps when camwalk is bad, so what's the difference?