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AIRHEAD VALVE ADJUSTMENT with Pics

Discussion in 'XJ DIY How-To Instructions' started by bigfitz52, Jan 6, 2009.

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  1. Craig B

    Craig B Active Member

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    You should be able to hear them tick?
    I would have thought a ticking noise would be a bad sign. lol
    Thankss
     
  2. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Ticking means that there is clearance betweeen the shim and the cam so that the valves can fully close.
    A short list of combustion engine valves that should be silent: Rotary valves, Reed valves, valves actuated via hydraulic lifters.
     
    Last edited: Feb 26, 2017
  3. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    At 200,000 mi, your valves are at their scheduled 40th valve shim clearance check.

    When you finally DO get them back in spec.....and then get the carbs back to where they belong-----you're right gonna find out just how much power you've lost along the way and don't even know it. She'll scare you all over again :)

    Dave
     
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  4. Franz

    Franz Well-Known Member

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    I will try the Yamalube 10W40 thanks.
     
  5. Craig B

    Craig B Active Member

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    Sounds awesome.
    Now i just need spring to arrive and maybe somebody to lend a hand. Never done either of those tasks before.
     
    Last edited: Feb 26, 2017
  6. Carson

    Carson Member

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    Is it absolutely necessary to replace the shims after you check the thickness? A local bike shop will trade me shims but they need them the same time I pick up the new ones. Will I damage the cam/buckets if I take all the shims out at once?
     
  7. Johnius

    Johnius Member

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    I'm glad you asked! Don't pull out the shims and rotate the cam on the buckets. I almost did and the guy who runs the shim pool here advised me against it.
     
  8. Craig B

    Craig B Active Member

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    Ok. I really Hate math.
    Measured my valve clearances today. My feeler guages increase in .05 mm increments. A 0.15mm feeler will not fit in on the intake side but a 0.10mm will. On the exhaust side a 0.20mm feeler will not fit but a 0.15mm will.
    My confusion starts here. If the clearance was for example 0.104mm and the shims are only available in 0.05mm increments when I add any shim it will put me out of spec on the loose side.
    I am kinda lost as what to do. Should I just leave well enough alone?
     
  9. Johnius

    Johnius Member

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    You're going to need tighter gages, hate to say it. The whole tolerance is .05mm. You have no way of knowing if you're in or out of spec with your current gages.

    ::Edit:: You can do it with .05mm increment gauges. I wasn't thinking it over properly.
     
    Last edited: Apr 15, 2017
  10. Craig B

    Craig B Active Member

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    I was thinking the same.
    However.
    What still makes no sense to me is if the shims are only avaiable in 0.05 mm then the valves cannot even be shimmed into spec unless the clearance is below 0.010mm
     
  11. Johnius

    Johnius Member

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    That's correct. In spec is in spec. Out of spec is out of spec. When you get to .10, you shim to .15 and you're in spec.
     
  12. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Look at the table in the first post.

    Also note that most metric feeler gauge sets come with thin brass feelers that are meant to be stacked with the other feelers in order to make a gauge that is between the 0.05mm increments (e.g. stack a 0.01 onto a 0.10 to make a 0.11).
     
  13. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    You NEED TO Have a feeler set that you can measure what the CURRENT and EXACT clearance is at a stone cold temperature.

    You also need to check the size of each CURRENT shim.

    NOW you check the chart..... match your current clearance with the current shim.

    If ANY intake clearance is ANYWHERE between .11mm - .15mm, you're in spec so leave that one alone.

    If ANY exhaust clearance is ANYWHERE between .16mm - .20mm, you're in spec so leave that one alone.


    You really don't need to do any math. Just triangulate the two lines on the chart. We just call it"doing the math".

    If you need more help start a conversation with me and I'll check your numbers for you.

    Dave f
     
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  14. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Actually the tolerance range is only .04mm.....
     
  15. Johnius

    Johnius Member

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    It's .05mm. .11 is in spec and .15 is in spec, which makes it an inclusive series, so you have to count both numbers with three in the middle.
     
  16. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    I guess it'll depend on how we want to look at it.

    I see it as:
    1-2
    2-3
    3-4
    4-5

    And for exhaust :
    6-7
    7-8
    8-9
    9-0

    But none of that really matters… In spec is in spec
     
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  17. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    I like that. Now, is zero a number?
     
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  18. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Yes. The origin. Number lines, graphs, and such.
     
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  19. Craig B

    Craig B Active Member

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    Just checked my valve clearances.

    Minimum of 200,000 km on my bike.
    I am the second owner. Original owner turned speedo over 100,000. I have done it twice myself.

    Here are my shim #'s.
    Oh BTW. Have never checked or replaced since I owned the bike.

    Intake #1 0.15. #2 0.13. #3 0.13. #4 0.12mm

    Exhaust #1 0.17 #2 0.17. #3 0.203. #4 0.17mm
     
    Last edited: Apr 28, 2017
  20. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Personally, I find that not believable at all. 300,000km ( "Original owner turned speedo over 100,000. I have done it twice myself. ") and almost all shims still above the middle of the tolerance range---riiiiggghhhhtt.
     
    Last edited: Apr 28, 2017
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