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GS500E: Valve Clearance Issue

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    GS500E: Valve Clearance Issue

    So, I bought a non-running GS500E. (Yeah I know...) It was last inspected in NY in 2013.

    Going through brakes, carbs and valves before I crank it.

    Everything is going pretty well except for valves. Specifically the left hand exhaust valve in fact.

    As dragged home, I could not measure clearance on either exhaust valve. My process in that case has been to swap in a thin (2.30mm) shim from a different bike, with a 25mm OD. Z1 shims arrived today and with a swap from inlet right to inlet left and two new shims the inlet valves and right hand exhaust valve are now measure 0.07 or 0.08mm gap.

    The left hand exhaust valve still measure no gap.
    - old shim was 2.65mm
    - swapped in the 2.30mm and measure 0.25mm gap
    - calculated that I needed a 2.50mm shim
    - as noted above installing that shim still shows zero gap

    My theory is that this bucket must not be perfectly flat? Using the 25mm test shim worked okay for the GS650 I dragged home a couple years back and for the right hand exhaust valve on this bike.

    I have carefully inspected with a flashlight and swabbed the bucket with a q-tip with no sign of any debris.

    I could order the next two size's of shim I suppose? Or I could order a thin one of the proper OD?

    That said, am I kidding myself that there is any chance I don't need to lift the head off? It appears the bike did run with the original minimum of 0.15mm interference on this valve.

    The bike has 18,600 miles on it. I had hoped to get the ole girl running before the snow flies, I guess that is the only reason I am not ordering 2.30mm thick 29.5mm OD shim right now.

    Ok, fire away boys...

    Thanks, Alan
    '82 GS650G 27k
    '00 GZ250 5k "Pocket Hawg"
    ('98 GS500E 18k, new project - moved on to new home)
    '98 GSF1200 39k, new project, fixed the blown out spark plug, waiting on time
    '05 Moto Guzzi Nevada 750IE (the Pocket Hawg's days are numbered)

    #2
    Moving three shim sizes and still not getting clearance is a bad sign. Maybe the valve is damaged from not being adjusted? I'd be sure to rotate the engine several times before checking clearance just to be sure that the valves don't have any debris holding them open, and then check again.
    Ed

    To measure is to know.

    Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

    Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

    Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

    KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

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