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  • Valve Question

    I had a great weekend finishing the brakes on Gertrude with new Stainless caliper pistons all around and clear spooge holes. Now that it stops I got to ride it around the block for the first time since I got it 2.5 years ago. First impression - strong with lots of power. What a machine! The engine has a small backfire at idle that disappears with RPM chalked up to no Sync yet, but it was noisy. So pulled the valve cover yesterday and found the cam chain kind of loose in places. I had adjusted the chain according to the book, but it did not seem to work, so I pulled off the adjuster and saw it was kind of stuck in the bore. A good cleaning and lube and it gave a distinct thud when the spring pushed against the chain after re-install. Now the chain had a lot less play through all 360 degrees of crank rotation.
    So then onto the valves. Things are fairly tight at .005 - .006 but the exhaust valve on #3 cyl was .023 - really loose. <scratching head>. Not sure how that could happen unless someone had just messed up the adjustment or the valve is sinking in to the seat. I don't have any shims yet, so put it back together and it's much quieter (cam chain good) and #3 cylinder seems to be firing fine - the exhaust header is nice and hot...
    Going to hunt down shims this week - but any ideas what would cause just one valve to be .013 out of whack?
    When the horse is dead, dismount.

    Bagapotomus - '80G Attempted Rescue, '78 Engine, Vetter Bags and Trunk.

  • #2
    Check your compression on that cylinder, it may be stuck open or bent. It may be possible that they replaced the valve at one time and used the wrong one. (An intake vave from an XJ750 will fit the exhaust valve for the XS1100 but you will never get the clearence correct...so I guess that it really does not fit)
    Ty

    78 XS1100E - Now in Minnesota
    80 XS1100LG - The Punisher
    82 XJ1100 - Current project - The Twins
    82 XJ1100 - Wife's Bike - The Twins
    82 XJ1100 - Daughter's Bike
    72 Suzuki TS125 - Daughter's Bike
    72 Yamaha Mini JT2 - Youngest Daughter's bike (She wants a bigger one now)

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    • #3
      Off the top of my head I can say stranger things have happened. As the valve train wears on these machines it typically makes the valve lash tighter, not more loose.

      The valve shims will come in increments of .5 mm's and it might be helpful to check your valve clearance with a set of MM feeler gauges though using gauges in thousandths is Ok as long as you convert.

      Shims can be easily changed with the little valve tool but alot of guys dont like them. I have used them with success but if you are changing a bunch of shims it is sometimes easier to take the cams loose.

      Do a search on this site and you will find a bunch of info on checking clearances.

      Oh yeah, when you replace a shim make sure you put the size marking facing down (intot he valve bucket) otherwise the cam will rub it off.
      Mike Giroir
      79 XS-1100 Special

      Once you un-can a can of worms, the only way to re-can them is with a bigger can.

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