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'81 XJ750RH - valve clearances

Discussion in 'XJ Technical Chat' started by 99expytn, Sep 23, 2006.

  1. 99expytn

    99expytn New Member

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    I removed the valve cover today and measured the clearances. I was a little suprised.....the clearances that were out of spec. were too tight. I would have thought it would have been the other way (too loose). It's probably been 15 years since they were serviced. I thought I'd post my clearances and see what people thought. (Measurements are in mm)

    Exhaust (from left to right as if you're sitting on the bike)

    Measured: 0.152
    Shim: Y275

    Measured: 0.178 (in spec)

    Measured: 0.178 (in spec)

    Measured: 0.127
    Shim: Y275

    Intake (from left to right as if you're sitting on the bike)

    Measured: 0.076
    Shim: Y290

    Measured: 0.102
    Shim Y285

    Measured: 0.076
    Shim: Y290

    Measured: 0.127 (in spec)

    I'm assuming I did it correctly (followed the service manual). I rotated the lobe until it was 180 from the shim and then inserted my feeler guage between the cab and the shim. The clearance that I recorded was the guage that would slide in. The next thicker guage would not slide in.

    It looks like all the shims need to step down one in thickness.

    One question, I removed the left side crankcase cover. Is there a gasket between this cover and the engine?

    Thanks,
    99expytn
     
    99expytn, Sep 23, 2006
    #1
  2. OU812didntU

    OU812didntU Member

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    theres supposed to be a gasket there, i cant help ya with the valve clearances measurments i dont know that much about it but am sure theres someone in here that can answer that for ya.
     
    OU812didntU, Sep 23, 2006
    #2
  3. Robert

    Robert Active Member

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    Location:
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    According to the Haynes:
    Inlet 0.11 - 0.15 mm / 0.004 - 0.006 in
    Exhaust 0.16 - 0.20 mm / 0.006 - 0.008 in

    There is a fine valve clearance shim selection chart in the Haynes and I'll look it up for you if you like but you really should invest in a book for your immediate use. It is worth everything you pay for it and more. Then get the XJCD (though it will be a while in coming), it is a great companion to the books.

    Exhaust: #1 change to a 270
    #2 and #3 are ok.
    #4 change to a 270

    Intake: #1 change to a 285
    #2 change to a 280
    #3 change to a 285
    #4 ok

    Hope this helps. I'm from the understanding that it is better to have it more to the loose side than the tight side. Best of luck!
     
    Robert, Sep 23, 2006
    #3

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