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Quick Question - Valve Shims & Noise

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    Quick Question - Valve Shims & Noise

    Last fall, when I started my project bike for the first time, there was a clacking noise coming from the top end somewhere, and after running it a few times, the noise quieted slightly but never disappeared. I torn down he top end this winter and everything looked good, well within spec, but when I started it this spring the noise is still there?

    My initial thoughts were cam tensioner, but it seems to be functioning fine? So now I'm wondering if the valve shims clearance isn't sufficient? I know they are close to being too tight, but before I order new shims, would that explain the clacking noise?
    1982 GS650e - Cafe or Scrambler...that is the question...

    #2
    Originally posted by KillerGriller View Post
    Last fall, when I started my project bike for the first time, there was a clacking noise coming from the top end somewhere, and after running it a few times, the noise quieted slightly but never disappeared. I torn down he top end this winter and everything looked good, well within spec, but when I started it this spring the noise is still there?

    My initial thoughts were cam tensioner, but it seems to be functioning fine? So now I'm wondering if the valve shims clearance isn't sufficient? I know they are close to being too tight, but before I order new shims, would that explain the clacking noise?
    By all means take the time to get the right shims in place. The common reason why you'll still get noise is from a condition known as "Cam Walk" and is a well known issue caused by plain old ordinary wear. If you do a search you'll find plenty of info on this site on the subject, it's considered to be "normal"
    1980 Yamaha XS1100G (Current bike)
    1982 GS450txz (former bike)
    LONG list of previous bikes not listed here.

    These aren't my words, I just arrange them

    Comment


      #3
      Originally posted by LAB3 View Post
      By all means take the time to get the right shims in place. The common reason why you'll still get noise is from a condition known as "Cam Walk" and is a well known issue caused by plain old ordinary wear. If you do a search you'll find plenty of info on this site on the subject, it's considered to be "normal"
      Cheers, I'll look into it
      1982 GS650e - Cafe or Scrambler...that is the question...

      Comment


        #4
        And honestly it isn’t much to worry about
        sigpic
        Cowboy Up or Quit. - Run Free Lou and Rest in Peace

        1981 GS550T - My First
        1981 GS550L - My Eldest Daughter's
        2007 GSF1250SA Bandit - My touring bike

        Sit tall in the saddle Hold your head up high
        Keep your eyes fixed where the trail meets the sky and live like you ain't afraid to die
        and don't be scared, just enjoy your ride - Chris Ledoux, "The Ride"

        Comment


          #5
          Originally posted by KillerGriller View Post
          My initial thoughts were cam tensioner, but it seems to be functioning fine? So now I'm wondering if the valve shims clearance isn't sufficient? I know they are close to being too tight, but before I order new shims, would that explain the clacking noise?
          If the valve clearance is not sufficient, there would be LESS noise, not more.

          Well, at least until the valves burnt, then there would be a LOT of noise, if the engine even ran at all.

          What makes you think the tensioner "seems to be functioning fine"?
          You can't see it in operation, you can only see the results if it's NOT functioning fine.
          If you're not living on the edge, you're taking up too much space.

          Comment


            #6
            Originally posted by Who Dat? View Post
            If the valve clearance is not sufficient, there would be LESS noise, not more.

            Well, at least until the valves burnt, then there would be a LOT of noise, if the engine even ran at all.

            What makes you think the tensioner "seems to be functioning fine"?
            You can't see it in operation, you can only see the results if it's NOT functioning fine.
            I would expect that too -> less valve clearance = less noise until catastrophe, but it's worth an ask. What about "No" clearance between the shims and cam lobes? I will be pulling the cylinder cover tonight to take a look at them and measure, but out of curiosity?


            "Cam Tensioner seems to be functioning fine" is based on it's behavior during reassembly and when I had to adjust the cams to line them up for timing. It may be misbehaving, if a clacking sound is typical of a malfunctioning tensioner it'd make sense. I'll check it again tonight when I have the cover off.

            Also, this isn't the typical ticking of an older engine, it's a separate/distinct "clack-clack-clack" sound at the same time, the bike sounds like a tractor.
            Last edited by KillerGriller; 05-27-2021, 04:59 PM.
            1982 GS650e - Cafe or Scrambler...that is the question...

            Comment


              #7
              If the cam chain was too loose, it could slap against the cam cover. Best way to ensure that tensioner is working properly is to remove it and fiddle with it in your hands- you’ll quickly figure it out as how the lock screw and lock nut are designed to work. The tensioner plunger shaft must be able to slide out,but not push back .
              1981 gs650L

              "We are all born ignorant, but you have to work hard to stay stupid" Ben Franklin

              Comment


                #8
                Originally posted by KillerGriller View Post
                Cheers, I'll look into it
                A very recent discussion on cam walk can be found here.



                I haven't noticed it on my 850 which has 52K miles on it. I wonder if it only becomes an issue on some engines and not others.
                Roger

                Current rides
                1983 GS 850G
                2003 FJR 1300A
                Gone but not forgotten 1985 Rebel 250, 1991 XT225, 2004 KLR650, 1981 GS850G, 1982 GS1100GL, 2002 DL1000, 2005 KLR650, 2003 KLX400

                Comment


                  #9
                  Originally posted by Burque73 View Post

                  I haven't noticed it on my 850 which has 52K miles on it. I wonder if it only becomes an issue on some engines and not others.
                  My 80 engine only does it when warm and only sometimes at that.
                  Today, it started doing it as soon as it ran.
                  Ach, who knows why - it's one of those things.
                  Just thought of something - the previous slack time it was on the sidestand for a fortnight. Normally, it's on the centre stand.
                  ---- Dave
                  79 GS850N - Might be a trike soon.
                  80 GS850T Single HIF38 S.U. SH775, Tow bar, Pantera II. Gnarly workhorse & daily driver.
                  79 XS650SE - Pragmatic Ratter - goes better than a manky old twin should.
                  92 XJ900F - Fairly Stock, for now.

                  Only a dog knows why a motorcyclist sticks his head out of a car window

                  Comment


                    #10
                    Originally posted by Grimly View Post
                    My 80 engine only does it when warm and only sometimes at that.
                    Today, it started doing it as soon as it ran.
                    Ach, who knows why - it's one of those things.
                    Just thought of something - the previous slack time it was on the sidestand for a fortnight. Normally, it's on the centre stand.
                    That's interesting. While at rest 99% of the time mine is on the center stand. FWIW
                    Roger

                    Current rides
                    1983 GS 850G
                    2003 FJR 1300A
                    Gone but not forgotten 1985 Rebel 250, 1991 XT225, 2004 KLR650, 1981 GS850G, 1982 GS1100GL, 2002 DL1000, 2005 KLR650, 2003 KLX400

                    Comment

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