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Thread: 2011 R1200GS - Hemisphere valve shims - 0.05 mm increments - a puzzling observation..

  1. #1

    2011 R1200GS - Hemisphere valve shims - 0.05 mm increments - a puzzling observation..

    A puzzling observation...

    At 136,000 km I am going to change two valve shims to the next largest size as the valves are at the loose end.

    What's puzzling\surprising is that even though the replacement valve shims are only available in 0.05 mm increments, the original shims are engraved to three decimal places, not two. My original exhaust valve shim is engraved 5.275X and my original inlet valve shim is engraved 5.475X.

    I would have expected the original shims to be engraved to two decimal places, not three.


  2. #2
    i should be out riding! wyman.winn's Avatar
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    Quote Originally Posted by 141987 View Post
    A puzzling observation...

    At 136,000 km I am going to change two valve shims to the next largest size as the valves are at the loose end.

    What's puzzling\surprising is that even though the replacement valve shims are only available in 0.05 mm increments, the original shims are engraved to three decimal places, not two. My original exhaust valve shim is engraved 5.275X and my original inlet valve shim is engraved 5.475X.

    I would have expected the original shims to be engraved to two decimal places, not three.

    my take is the factory will get the valve clearances as close to optimum as possible and use 3 digit shims to do that...bear in mind that the 3 digit shims are in increments of .005mm or about 0.000196" while the 2 digit shims are in increments of .05mm or 0.00196"....

    i think getting the clearances within about 0.002" is pretty dang close enough...!!!
    ~wyman~

    2015 BMW S1000R - Duke - Black Storm Metallic
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