I've gone through the engine noise threads but haven't found this particular eccentricity.
I get a knocking noise at idle, which disappears with revs, coming back after an intermittent period. However, this only occurs when the bike is leaned over to the left. No other time I have noticed (not leaned off the the right or anything). If I get the noise I can lean the bike up and the noise goes away. The noise generally continues for about a second, drops off, then goes on for about a second (period is not static). It only seems to be from the left side of the engine.
It has only started happening recently, it seems from the other threads that it shouldn't be anything too serious, I'm thinking about pulling it apart in a few weeks to have a look.
Does it sound like cam chain (maybe valve slap according to some) to everyone else?
Donno we can't "hear" it thru the BBS. hehehe
Ok seriously. How many miles are on that bike/engine? Is this knock really loud or subtle?
"Knock" is usually assciated with bad bearings, either main crank, con rod, or, in the GS's case the counter balancer. BUT they aren't usually associated with a vertical orientation. The crank et al, usually have enough rotational enertia that they don't care. I suppose because of the low idle speed it might be a thrust plate or a bearing going... I doubt its valves, when they are off its more of a "tick tick tick tick..." To see if its a timing chain or the tensioner, manually tighten up the tensioner to see if the noise goes away.
GSs also tend to vibrate apart if you aren't careful, and they aren't built with the absolute best materials. So before you tear your engine down looking for a problem, check the torque on the engine mounts, the exhaust headers, and anything else you can think of. When leaned over the frame can flex and cause the engine to vibrate against it.
hope this helps,
My money is on valve clearance... Somehow the leaning seems to get some oil off from the puddle around the bucket... and is causing it to clack. Anyway this bike is notorious for valve noise... so I wont be surprised at all if the valves are within spec and it still make the noise it did.
Cool.
Srinath.
Cheers guys. Seems like it deserves a good going over. I'll have to have a quick look this weekend. Before that though I'll check the bolts as I have some vibration ~4,500rpm that I'd like to sort out as well.
The noise is a more a clack than a obvious knock, and it's definitely not loud.
The engine has actually just gone over 100,000 kms (~60,000 miles), I only bought it a few weeks ago and have put 2,000 kms on it so far. I've only noticed the noise in the last 200km's or so, and it doesn't happen all the time. Goes pretty well for something with that sort of use, and is exactly what I wanted for my first bike.
Impressive mileage :)
My GS knocks too at idle, it depends on the brand of oil I use. It can be heard best with Castrol GP. The engine has to be hot, otherwise it will not occur. The hotter the engine, the more and longer it will knock.
It's probably nothing special since a lot of GS's have that knock, but I would keep an eye on it because of the high mileage.