which shims to replace?

[Jenya]

Hello,

This the first time I perform valve adjustment. Here is the gaps I measured:

Exahust: Left   - 0.05-0.06 (5 doesn't bite in, 6 doesn't go in, so I figure it is somewhere in between)
             Right - 0.08-0.09

Intake:   Left   - Less than 0.03 (obviously this calls for a thiner shim)
             Right - 0.03-0.04

From this, it looks like two valves are on the border line of tolerance : 0.08-0.09 and 0.03-0.04

Do I leave them and recheck after a while? if so, what would be a reasonable period of time after I should check again?

Jenya

[Kerry]

One's too thick and one's too thin?  Hmmm ....

There is a (small, but nonzero) chance that you could actually switch those two shims.  The factory shims on a given bike don't seem to vary by more than a size or two.  But you won't know for sure until you find some way to pop them out and read or measure them.  (Measuring is better than trusting the number printed on it ... but I have not found very many to be off.)

Unfortunately, unless you can get them both out at the same time you'll need a third shim.  You don't want to be cranking the engine around with a shim missing.

[Jenya]

Well, after turning the engine and re-measuring, I now get different readings. In fact, the valve that I thought definitelly needs to have its shim replaced, because last time I couldn't slip in even a 0.03 blade under, this time allows a 0.04 blade in. I guess the position of lobes was slightly different last time.

So my question is - do I position lobes vertically to a shim, or in a position that allows for the largest gap?

Jenya

[Kerry]

I used to think that "vertically to the shim" was correct (and it's probably not bad) but Clymer is fairly adamant about using one of these positions instead:

[Jenya]

yep Right after I posted, I decided to consult Clymer and leartn about the whole procedure of turning the crank with a 19mm wrench and aligning the marks for two configuration. I just finished doing all that and collected the numbers. One of the intake valves was indeed tight. I replaced the 265X shim with 260 and and it got to 0.06.
I can also use 262 shim, for 0.04mm clearance. Which one is better: 0.06 or 0.04? I am thinking 0.06.

Interstingly, both 265X and 270X shims don't measure what they say. It almost seems like 'X' means something. 265X is actually 268 and 270 is 273. Also, both are of a blacker metal than regular, non 'X' shims, that measure pretty much eaxctly to what is written on them.

Need to get two 275 shims tomorrow for exhaust. Both exhaust valves are loose.

Jenya

[Kerry]

Which one is better: 0.06 or 0.04? I am thinking 0.06.

Yep, that's my vote. 

[runsilent]

Hello,

This the first time I perform valve adjustment. Here is the gaps I measured:

Exahust: Left   - 0.05-0.06 (5 doesn't bite in, 6 doesn't go in, so I figure it is somewhere in between)
             Right - 0.08-0.09

Intake:   Left   - Less than 0.03 (obviously this calls for a thiner shim)
             Right - 0.03-0.04

From this, it looks like two valves are on the border line of tolerance : 0.08-0.09 and 0.03-0.04

Do I leave them and recheck after a while? if so, what would be a reasonable period of time after I should check again?

Jenya

GS500 valve clearance according to Owners Manual is .03-.08mm  (.0012-.0031").  I'd button that up and go ride and check it again in about 8k miles.   

I've got an old 97 GS500E with 80k miles on the clock that is just sitting in the corner of the garage rusting away.     I checked the valves on it at 600 miles and again about every 8k miles thereafter.  It was last checked at 76,800 miles.  The 2 intake valves are still with their original shims never having been changed.  No shims were changed on the exhaust valves till 40k miles when one exhaust valve was changed.  That valve was changed again several times and is now with a minimum standard shim.  The other exhaust valve was changed a couple times also to thinner shims.  I became inclined to set them at max clearance or a bit over since they were always getting tight, not loose.  Seems the GS exhaust valves tend to recede into the seats over many miles.  Your seats may be different.