Shim sizing...

[Guest]

I checked clearances on my valves and I couldn't get my thinnest gauge (.0015) in between the lobe and shims on 6 of my 8 valves. 2 I had enough clearance for my .002 gauge, which is borderline within spec.

Here's what I've got:

Cylinder	1	2	3	4
Exhaust Clearance (in/1000)	-	-	0.002	-
Shim	2.50	?	2.60	2.60
Intake Clearance (in/1000)	-	0.002	-	-
Shim	2.55	?	2.55	2.60

As you can see... Ex 1, 2, and 4 and In 1, 3, and 4, I couldn't get a clearance reading, thats how tight they are. Shims on Ex 2 and In 2 are both unmarked, or the numbers wore off. I plan on moving the shims around a bit, putting my smaller shims on valves I could not read to see if can get a measurement with the smaller shims to have a better understanding of what I'll need. Any suggestions?

[sam000lee]

Nope sounds like you've got the right idea. If your smallest shim still doesn't have any clearance you'll need to order a thinner shim to get the proper readings. If you can't get a feeler gauge in but can spin the shim bucket then it might only be one size off.

[Steve]

When you move your shims, put SOMETHING in place of the shim or you WILL damage the cam lobe.

A quarter will work well enough, just don't plan on dropping it into a vending machine later.

I keep hearing that "one size smaller if the bucket spins" theory, but have experience otherwise. I had one bucket that spun easily, but had to drop three shim sizes. That film of oil does a wonderful job.

If you plan on using the GSR Shim Club, let him know that you will need some extras in various sizes smaller than what you have, he will send what you need. Just send all the unused shims back when you are done.

You really need to get a caliper to measure your unmarked shims. Harbor Freight has sales going all the time, you can get a 6" caliper for as low as $10, and it will do just fine to determine your shim size. Also, read the shim carefully. Have a good light nearby, move the shim around to catch the light at different angles. You can sometimes catch a hint of the size by doing that. Also, be aware that there might be an "X" after the number. That is important, it signifies a 'half-size' shim that was only available at the factory. If you are really anal about setting the clearances in a very small range, you can use those.

.

[748cc]

Re-instating this valve shim inquiry:

I bought a few K&L shims recently, and took my HF calipers to them before making placement selections-they all seemed to be off by as much as +.003mm. My question is: How accurate are K&L shims to their posted sizing and to what tolerance are held to? There was mention elsewhere of K&L shim quality being sub-par at one time, but they were discussing shim breakage rather than sizing differences. Then again, my HF calipers could be off by a few degrees, so... what's more likely? TIA for your replies.

[bwringer]

A few points to make:

- Be VERY VERY VERY careful about mixing units. You mentioned .003mm, but those calipers can only resolve .01mm. Did you mean .03mm or .003 inch?

- Those calipers read in .01mm, but they're not actually capable of that level of accuracy. It also takes practice to learn the right "touch" for maximum repeatability and precision (how much pressure you apply, etc.). They are very useful for distinguishing one size of shim from another at a very low cost, but you can't put a lot of stake in that last digit. (Make sure you understand the difference between accuracy and precision.) Also, K&L shims come with a protective coating of some sort of waxy stuff that affects this measurement; you have to clean this off.

For example, if you measure two unmarked shims with these calipers and you get 2.64mm and 2.72mm, you can reasonably conclude that they're probably nominally 2.65mm and 2.70mm shims. So if you measure the shim that came out at 2.72mm and you measure the replacement at 2.64, then you can be fairly confident that it's the next size down.

- If you really want more accurate and precise shim measurements, I'd suggest the Harbor Freight digital micrometer. $30 with a coupon, and it has the precision and accuracy needed to confidently measure in .01mm increments; there's a little "clicker" that ensures consistent tension and it reads directly in mm. The one caveat is that you should remove the battery between uses, and keep a few spare batteries around; the inexpensive stuff like this tends to keep draining the button battery even when it's turned off. A Starret or Mitutoyo won't drain its battery, but it costs about ten to fifteen times as much... you can buy a lot of button cells for that $300.

https://www.harborfreight.com/digital-micrometer-63647.html

I've found using a micrometer that there's a little bit of variation in OEM and aftermarket GS shims, but overall the aftermarket shims actually tend to be a little closer to their marked size.

In other sizes of shims used on other bikes (like the little shim-under-bucket shims used in V-Stroms and such), the OEM shims also wander around a bit but the aftermarket shims I've measured have almost all been dead on.

[748cc]

Thanks bwringer-all very good advice Yeah, 0.03mm is what I meant to say. For instance, a shim stamped 2.65 is actually reading 2.68; another stamped 2.60 is reading 2.63. I bought lots of 5pcs in each of those sizes hoping to 'dial in' my valve train with 'less than accurrate' samples-i've succeeded in that regard. As for coatings, these only came lightly coated in oil-no wax, paper, adheasive backings, etc. The tool being HF had me wondering where to point blame for the off reads, that's all. If someone claimed they too found K&L shims way OoT I'd have tilted the scales in that direction.
Thanks again, sir!

[Steve]

For instance, a shim stamped 2.65 is actually reading 2.68; another stamped 2.60 is reading 2.63.

If those are OEM shims, make sure they don't have an "X" after the number. A 2.65x shim should measure 2.675mm, which you could easily read as 2.68. Same thing for a 2.60x, it should measure 2.625, which could be read as 2.63.

I don't know of any retail outlet where you can order any "X" shims, if you want to be that precise in your adjustment. The only place that I know of is the GSR Shim Club. (<-- click link) Ray keeps a good stock of shims of all sizes. The basic concept is to determine what you think you might need, contact Ray. He will send what you ask for. When you are done, send the leftover shims back, along with a small donation to the cause, you are done. If you want to build up your own stash of shims, the best source is Z1 Enterprises.

Lastly, please feel free to take advantage of the offer in my signature. Just a simple calculator to help you determine which shims you might need, and a handy log sheet to keep track of what you have done.

.

[748cc]

Thank You, Steve. No OEM pcs in this lot, only K&L knockoffs. And, I'd not have dived in without your spreadsheet, Sir-super easy & well calculated! No GS rider should be without it, cause it also doubles as a maintainence log-much neater than a scribble pad!

[Grimly]

Re-instating this valve shim inquiry:

I bought a few K&L shims recently, and took my HF calipers to them before making placement selections-they all seemed to be off by as much as +.003mm. My question is: How accurate are K&L shims to their posted sizing and to what tolerance are held to? There was mention elsewhere of K&L shim quality being sub-par at one time, but they were discussing shim breakage rather than sizing differences. Then again, my HF calipers could be off by a few degrees, so... what's more likely? TIA for your replies.

I got a few new shims recently and one of them was wildly wrongly marked. What should have been a 2.55 was a 2.15. Due to the measuring fairies I was fine though, as a bit of shuffling around brought all of my gaps to the wide end of tolerance. I bought a bit more time and allowed for settling in after the rebuild.
I let the shim supplier know, but he obviously couldn't care less, as I heard nothing back.
During the rebuild I had acquired a couple of random lots of shims and went through all of them with the digi calipers, engraving them with their actual sizes for future reference, then stacked them neatly into groups and stored them in pill bottles. Should make future gap-setting less time-wasting and traumatic.