checked the valve clearance on my K100RS 1985 todat and it seems that some shims need to be replaced.
The only thing that I am wondering about is the standard thickness of the shims. I can order new ones but I need to know the standard thickness of the shims to compare them with with my measurement. I gues the only good way is to remove the faulty ones, measure those and then see what new ones I need to order?

thanks

That's the only way. With any luck you'll find that some of the existing shims can be used in other valves.

that would be nice.

If you measure the shims use a Micrometer, Vernier calipers will not give an accurate reading because they measure the thickness at the outer edge.
If you find any dishing or damage to the running surface DO NOT turn them over discard them.

For your info on getting shims


Valve Shim Alternatives
 
KAWASAKI/YAMAHA BMW 29MM DIAMETER SHIMS
•KAWASAKI: KL600/KL650/KLX650 (85-98), Z1/KZ900 (73-76), KZ1000/1100/ZN1100 (77-85), KZ1000 Police (82-98), KZ1300 (79-82), ZN1300 Voyager (83-88) •YAMAHA: XS400 Maxim & Seca (82-83), FJ/FZ/YX600 (84-90), XJ550/650/750 (81-83) XS750/850/1100/XJ1100 (78-82
 
COME IN INCREMENTS 0F .05MM----FROM 2.00MM~3.10MM
 
Valve shim in half sizes
 
The BMW shims are available in .05mm increments from 2.00 to 3.00mm. I find
that I almost always am using the shims in the 2.35 to  2.70 mm range. In fact,
I just looked in all three boxes of K valve shims in the shop, and cannot find
any worn shims larger or smaller than that range. (Yes, I  save used shims. But
I save used air filters and drain plug gaskets, too. Never know when Brian
Curry might drop over and need some parts...
 
Many years ago, I discovered (like many others) that the Kawasaki and Suzuki
29mm shims fit perfectly in the BMW K models. Oddly, they cost more than BMW
shims, or they did then. But the fact that they fit the Japanese bikes made a
market for the aftermarket guys, so shims came available  from aftermarket
suppliers like Parts Unlimited. Some sold "half-sizes", i.e. shims in 0.025mm
increments. I have several in my shim boxes. I honestly do not know if Motion
Pro or Parts Unlimited still offers these finer sizes, but I found them useful
for getting spot-on consistency in valve adjustments, which DOES  make a very
slight difference in tuning.
 
http://www.parts-unlimited.com/dealers.html


I found when I did mine that I only need a couple of shims. I was able to swap them around to get good values.

A very simple job with the correct tool. There is a horror video on net of a guy using a screw driver and grinding shims to make thinner 

Beware the Yamaha shims that have a chamfer on the edge they can damage your BMW camshafts.

Hi Rick,

I didn't know about this. Is it an issue where the chamfer to flat top end, i.e., the edge at that point?

Thanks,
Glenn

That's the spot, the Yamaha cams have a smaller base circle and the lobes don't come as close to the edge of the shim.
The Kawasaki cams were OK but I have found the BMW cams come almost to the edge of the shim so you need to steer clear of the Yamaha shims just to be on the safe side.

Good thanks Rick!