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Valve clearance / 1st timer

Discussion in 'XJ Technical Chat' started by maxim82, Mar 30, 2013.

  1. maxim82

    maxim82 Member

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    I measured all 8 valves and was unable to get any readings so obviously ALL are too tight.
    Here's the breakdown>>>
    Exhaust 1) 275 shim, 2) 270, 3) 275, 4) 275
    Intake 1) 280, 2) 285, 3) 285, 4) 280
    I switched the 2) 285 with the 2) 270 and was able to get .010 reading, but no way could I get a .012 reading. The .010 is still too tight so I say I need a 265 shim.
    Should I drop down 20 on all my shims? That would give me three 255's, one 250, two 260's and two 265's.
    Any suggestions, calculations or ideas would be appreciated.
    1982 Maxim XJ650J / 12800 miles / Original shims
     
    maxim82, Mar 30, 2013
    #1
  2. ecologito

    ecologito Well-Known Member

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    Are your feeler gauges metric? I made the mistake of having SAE feelers and didn't do it for me.

    Try to get some sort of reading with the 270 shim, otherwise you may wanna get something that you know is loose but will give you a reading.

    Once you have a reading you can figure out what you need based on this chart:

    http://xjbikes.com/Forums/viewtopic/t=15972.html

    Good luck
     
    ecologito, Mar 30, 2013
    #2
  3. maxim82

    maxim82 Member

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    Yeah I have a metric feeler gauge. I just thought going from a 285 shim to a 265 was quite a jump, but that's how I see it. So I'd say I need to change all my shims by 20 to have them in spec.
     
    maxim82, Mar 30, 2013
    #3
  4. MiGhost

    MiGhost Well-Known Member

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    As Eco mentioned. Get yourself one shim at 255, or 260 so that you can accurately measure the clearances. Then you can set them correctly.

    But first!
    Get a compression test done on that engine ASAP! Both dry, and wet.

    With valve clearances that tight. The chance of a burnt, or warpped valve is very possible. It is hard to believe that the bike was even able to run.

    Ghost
     
    MiGhost, Mar 30, 2013
    #4
  5. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    I wouldn't bother with a compression test beforehand. With all of the valves tight you won't get any sort of representative results.

    From dead-tight, needing two or three sizes smaller shims to get in spec isn't uncommon. Four sizes (.20mm) probably won't be necessary on the intakes.

    The best thing to do is "walk" a smaller shim through each dead-tight position until you can get actual readings and then calculate from there. If you just assume .20 on all of them, you may need to go back on a couple.

    Good catch, let's hope you've caught it in time.
     
    bigfitz52, Mar 31, 2013
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