Hello all,
I own two high mileage 1985 K100 (RS and RT), amongst other bikes. I'm in the process of checking valve clearances. All valves on both bikes are tight and need adjustment. I'd like to remove all shims and then see if any of the shims can be swapped to a new location, before ordering extra shims? Or would I cause damage to the valves by rotating the camshaft with a wrench without shims in place? What about having shims re-machined by a professional machine shop? Better to buy new?

Thanks!

Why not systematically remove, record and replace each shim in sequence, noting in a chart the printed shim thickness as you progress through all 8 shims?  Then, measure the gaps, do your math and that will provide a final strategy to swap shims where possible and replace those that cannot be swapped.  Record your numbers in this chart:  http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/4valves/4valves.htm

The surface of the shims are hardened and machining them will compromise the hardening, causing premature degradation.  Better to shop new.

Thanks for your reply. Sure, you could do that but that doesn't answer my question... I was curious about whether it is ok to remove a shim and then rotate the camshaft.

I can't believe that it is a good idea to do that.  The cams might contact the bucket edges and potentially damage them if so.  I'm sure others will pipe up and possibly counter that opinion.

BTW, you can use Suzuki shims in these engines. Suzuki shims might be more readily available.

robmack wrote:I can't believe that it is a good idea to do that.  The cams might contact the bucket edges and potentially damage them if so.  I'm sure others will pipe up and possibly counter that opinion.

BTW, you can use Suzuki shims in these engines.  Suzuki shims might be more readily available.

Don't rotate the engine without the shims it will cause damage. Kawasaki shims also fit but beware of the Yamaha shims they have a small champfer which I believe will cause premature wear on the cams. Always measure the shims at the centre using a micrometer because vernier calipers will give a false reading on worn shims.

Thanks for the replies. I just wanted to make sure that it was a big no-no....

Best price for new shims:

https://newmotorcycleparts.net/motor_parts/valve_shims.html