Anyone ever use the valve shim selection chart??

[Guest]

Hi All, Currently working on an '83 GR650 Tempter...I know, not a GS...but have a shim question. My official GR shop manual has a page with a Shim Selection Chart which shows an easy way to pick and replace the valve shims.

Basically, it gives an example as such: If your clearance is (X) and your current shim is size (Y) then replace it with shim size (Z).

Seems easy enough but most posts on replacing shims here say to have a broad range of different shim sizes and go through the process of replacing shims and rechecking clearances until you get the right clearance.

Is this a good way to do your valve shims? Has anybody ever tried it this way? Going to be checking the valves clearances real soon and just thought if I could do it easier and cheaper, why not. Let me know what you think.

 

[chuck hahn]

Personally shoot for the .05MM at the mid range. I check the clearance on each valve and see what each is at. Then the ones that i feel need tweeked, I pull that shim and see what it is and do the math. For instance..If exhaust 1 reads in at.03 MM and its a .270 shim, then the optimal shim to get it to the .05 midrange would be a .268. But since the dealers basicall sell in incriments of 5 on the shims, then a .265 would put me atthe .08 upper limit. See what i am trying to explain? Youd be best served to check all the clearances, record what each valve is currently at and then check the shims on the ones you feel need tweeked. Have some good calipers or a micrometer handy to check the thicknesses as well. The shim club most likely will have the in between sizes you may need. When you install new shims, place the numbers on them towards the valves..this keeps the cam lobes from wearing off the numbers so they can be read again in the future.

 

[7981GS]

I have several of each shim size and as all of them have been used, I don't believe that one of them is what it is stamped.
What I do, is measure the gap, measure the shim that you pull out and then see which one of the used shims comes closest to the desired gap.
Of the 2.60's, for instance, they measure from 2.52-2.59.

Daniel

 

[chuck hahn]

I always measure them too..some are spot on and some arent. Good mic or calipers are a must for sure.

 

[Guest]

Ok guys, I get what you're both saying. And that is the usual way to do it. Thanks.

I was just intrigued that the shop manual has a chart and a way to pick the supposedly right size shim and was wondering if anyone has tried this before. It seems to make since...as long as each shim you're putting in has been checked that it's the actual size it's supposed to be..and since it's a Suzuki shop manual, I guess the shop technicians did this? Hmmm..