Valve knock?

[lawman]

My bike is finally running, great, but...

I had trouble with the exhaust valve shims being way off.  I got that fixed.  When I first ran the bike it was great.  Now, after about 15 miles of puttering while I adjust things, there's a knock when I accelerate.  Not always, just with hard acceleration, and it's not all that noticable.  I thought it was a loose bolt at first.  Now I think it's coming from the valve cover.

When I did the shims I checked again and again, and it was within spec.  The high end of spec, but within spec.  I had blown the oil out of the shim bucket with compressed air, but I am wondering if I got Buddha's oil float anyway.

Am I right that this is probably loose shim related valve knock?  Is this somthing I can live with, or do I need to worry about it?

[ATLRIDER]

May sound obvious but you should take the valve cover back off an recheck your valve clearances.  If the knock wasn't there b4, then somethings off or been disturbed.

[gsJack]

Sounds like gas knock if only when accelerating after engine is hot, could be you have some compression now.  If your using regular gas try a tank of premium just to see if it goes away.  Can't remember what year bike and how many miles you have on it.  Could be a different grade of oil coild get you back to regular gas if that's the problem.

[5thAve]

start by rechecking valve clearances.  Be sure the engine is cold when you do this.

+1 GSJack and detonation. Rule this out with premium unleaded.

certain model years have a problem (not serious) with excessive end play in the cam shafts. Makes a knocking sound from the valve cover area. Search this forum for more discussion. I forget the fix.

[lawman]

2004 with about 14k miles.

It was running like crap when I got it, so I can't really compare now to then, which is why I hit you guys up.

This is stupid, but I think you're totally right about the gas - didn't even think about it...  My last bike was a 1979 - I could drink a 5th and pee in the tank and it would run.  I will toss some octane boost in there, and then hit premium when I fill back up.  The valve knock didn't make sense to me - I triple checked those clearances.

Nice to be riding again... though last night was 40 degrees.

[ivany]

2004 with about 14k miles.

It was running like crap when I got it, so I can't really compare now to then, which is why I hit you guys up.

This is stupid, but I think you're totally right about the gas - didn't even think about it...  My last bike was a 1979 - I could drink a 5th and pee in the tank and it would run.  I will toss some octane boost in there, and then hit premium when I fill back up.  The valve knock didn't make sense to me - I triple checked those clearances.

Nice to be riding again... though last night was 40 degrees.

Just FYI, GS is not far off. The engine design is from the 70s...

[lawman]

Perhaps, but the carb was updated in 2001, the 04 GS500F has a TPS update, and low octane gas is a known problem for these.

[joshr08]

im not understanding how 87 octane gas would be the problem.  thats what this low compression motor is set to run on from the factory.