shims - exhaust

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  • Sexysuzi
    • Feb 2026

    #1

    shims - exhaust

    Hi,

    Just serviced the shims on my gs 550.

    I have one question:

    An exhaust shim,

    Current 2.65 - Space - 0.04 (with a little push..)


    Shall i replace this with a 2.60 shim - space 0.08, 0.09 with a push.


    Thoughts?
  • hampshirehog
    Forum LongTimer
    Past Site Supporter
    • Oct 2007
    • 12675
    • Hampshire. UK

    #2
    Both are in spec so just toss a coin.
    79 GS1000S
    79 GS1000S (another one)
    80 GSX750
    80 GS550
    80 CB650 cafe racer
    75 PC50 - the one with OHV and pedals...
    75 TS100 - being ridden (suicidally) by my father

    Comment

    • Agemax
      Forum Guru
      • Apr 2008
      • 8371
      • plymouth uk

      #3
      slacker is better, go for the swap. wont have to worry about changing that one again for a long while.
      1978 GS1085.

      Just remember, an opinion without 3.14 is just an onion!

      Comment

      • hampshirehog
        Forum LongTimer
        Past Site Supporter
        • Oct 2007
        • 12675
        • Hampshire. UK

        #4
        Originally posted by Agemax
        slacker is better, go for the swap. wont have to worry about changing that one again for a long while.
        You still have to check them though.
        79 GS1000S
        79 GS1000S (another one)
        80 GSX750
        80 GS550
        80 CB650 cafe racer
        75 PC50 - the one with OHV and pedals...
        75 TS100 - being ridden (suicidally) by my father

        Comment

        • Agemax
          Forum Guru
          • Apr 2008
          • 8371
          • plymouth uk

          #5
          Originally posted by hampshirehog
          You still have to check them though.
          true, but it wont need replacing
          1978 GS1085.

          Just remember, an opinion without 3.14 is just an onion!

          Comment

          • BassCliff

            #6
            Hi,

            I run all of mine on the loose end of the spec, or a little over. My last valve check had more than half the valve clearances at 0.10mm and the others at .07mm. I change the oil often, check the valves twice a year (every 5000-6000 miles), and I might change one shim each time. The engine has been very stable over the last 50,000 miles.


            Thank you for your indulgence,

            BassCliff

            Comment

            • Bonehead

              #7
              Previous posts are spot on. Having read just about a books-worth of information on valve adjusting/clearances looser is better. Having a valve even a little tight may be a disaster later on, especially if you arent religious about the maintenance. Added to the fact that the clearance is on the tight end of the spectrum with a push I would definitely replace. Better to do it now

              Comment

              • allojohn
                Forum Sage
                Past Site Supporter
                Super Site Supporter
                • Jan 2011
                • 3515
                • NoMo, MN

                #8
                Measure the all shims, new and old. They're not always what they say they are. Best be safe.
                -Mal

                "The only reason for time is so that everything doesn't happen at once." - B. Banzai
                ___________

                78 GS750E

                Comment

                • Sexysuzi

                  #9
                  thanks all. Decided to leave the shim in place. 0.04m clearance. will check in the next 6000 miles...:-)

                  Comment

                  • BassCliff

                    #10
                    Hi,

                    Originally posted by Sexysuzi
                    thanks all. Decided to leave the shim in place. 0.04m clearance. will check in the next 6000 miles...:-)
                    I always swap the shim on a .04mm clearance. I would rather have .09mm than .04mm clearance.

                    The factory manual states to check the valve clearance every 4000 miles. I check mine a little less often because I run them so loose all the time.


                    Thank you for your indulgence,

                    BassCliff

                    Comment

                    • Agemax
                      Forum Guru
                      • Apr 2008
                      • 8371
                      • plymouth uk

                      #11
                      I would have swapped them out while i had it apart....just my opinion
                      1978 GS1085.

                      Just remember, an opinion without 3.14 is just an onion!

                      Comment

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