Valve Adjustment - When to perform?

[markdjr]

Short of opening it all up and measuring, is there a way to tell when it's time for an adjustment? I have a 78 GS550 and it is running pretty well, however at 6k rpm's, (and occasionally a little lower or higher), I get a tinny rattling sound, high up, like near the gas tank or it almost sounds like it could be the keys rattling (its not). From what I've been reading it sounds like this could be a valve clearance issue. That sound right? Thanks.

[Skyboy8950]

Every 4k miles you are supposed to check it. So what are you waiting for?

[doctorgonzo]

Yep, should be on your list of things to do as soon as you get the bike, then once a year afterwards depending on how many miles you put on it.

[Nessism]

The valve clearance tightens with use so it’s unlikely you will notice increased noise when the valves need to be done – the opposite actually; a noisy valve is a happy valve to some extent on a GS engine so just follow the factory service schedule and everything should be fine.

[salty_monk]

Just a point on this.. once you know where they are 4k miles may be a little OTT for a check schedule.

I just checked the ones on my G after around 6k miles & they had moved by less than 0.01 in most cases.... I figure (as mine are all on upper end of spec) I likely have 20k miles to go before I'm out of spec, but I wouldn't recommend leaving it that long.
I will check mine either when I have it open for something else or about every 8-10k miles in future unless I get to the point where I cannot re-set one & it's marginal, in which case I'll know to check sooner next time....

Dan

[markdjr]

The valve clearance tightens with use so it’s unlikely you will notice increased noise when the valves need to be done – the opposite actually; a noisy valve is a happy valve to some extent on a GS engine so just follow the factory service schedule and everything should be fine.

Well if that's the case, any guesses what that noise is? Again, it's a tinny sound, like 2 pie tins lightly rattling on a bumpy road, sounds like it's coming from high up on the bike, I first suspected the keys. Thanks for the help.

[Skyboy8950]

It could be your break or clutch lever. That happened to me; you get to certain RPMs and it shakes the loose lever.

[Johnny K]

May be hijacking but what is the major reason for why the valves go out of "whack"? and have to do a valve adjustment. Just curious.

[Nessism]

May be hijacking but what is the major reason for why the valves go out of "whack"? and have to do a valve adjustment. Just curious.

The valve is clamped to the valve seat under spring pressure, and after opening and closing millions of times, the valve starts to pound into the seat thus causing the clearance between the valve and cam to decrease.

[Johnny K]

Thanks for the explanation. I know a little bit on how the engine works and so forth. Could anyone provide a link or two on how this engine works from spark/combustion to everything else. Or better yet an explanation for the newbs???