Tighter valve clearance after disassembly

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by JooG, Jun 14, 2018.

  1. JooG

    JooG Been here awhile

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    Just did the valves on my 03 950. The rear exhausts were to tight while the intakes were fine. I adjusted the exhausts. After putting everything back together, the exhausts were within spec, but both intakes were now too tight. I pulled it apart again and adjusted the intakes, so now everything is fine. I just found the tightening of the intakes strange. Is this... normal?

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  2. MotoActionADV

    MotoActionADV Level 16 wizard

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    I like to adjust the clearances, reassemble the camshafts/cambridge then take out the locking bolt and turn it over by hand a couple times to squish out any little amounts of oil and make sure everything is seated nicely and only then recheck the clearances.

    Did you do that?
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  3. JooG

    JooG Been here awhile

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    No, I didn't think of that. Makes sense though. I'll try it tomorrow.

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  4. mdethloff

    mdethloff Professional Disorganizer

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    Just to rule out simple mistakes, when you adjusted the intakes you did the math the correct direction and used thinner shims and not thicker ones right?
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  5. JooG

    JooG Been here awhile

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    Yes sir, I was on my A - game yesterday :) But as I said, it was strange that it changed without having been adjusted.

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  6. roookie1

    roookie1 Been here awhile

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    I have sometimes had the same experience. Valves that i havent changed shims on will change the gap a bit after assembly. My rule is: If it were in spec before disassembly, its also in spec after..
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  7. JooG

    JooG Been here awhile

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    Do you do the trick of turning over the engine a few times before remeasuring after reassembly?

    It's good that it happens to other folks - I was afraid that I had done something plain wrong.

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  8. roookie1

    roookie1 Been here awhile

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    Yes I do turn the engine over after assembly..

    The bike has gone more than 90K kms now, and no problems..So I will stick to that method.
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  9. keener

    keener Speed changes you.

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    That happens everytime.

    Just double check the math is ok and check the clearance after turning the engine as suggested. Check the clearances just to make sure they 're not way way far off in case you increased shim hight where it needed a shorter one for instance. Otherwise I ignore the incorrect gap after reassmbly.

    Cams get a good beating as the engine runs. You won't get a correct reading after reassmbling the cams unless you run the engine for a bit and thsts just neccessary if you do the math right.

    It's a common mistake where people read the clearances after reassembly and make further corrections. They almost always end up with larger clearances than spec.
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  10. JooG

    JooG Been here awhile

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    Ok, I see where you're coming from.

    I rechecked the recheck after turning the engine over a few times. Same measurements.

    I did change the intakes which were initially within spec, but not after the first reassembly. It's fine thought because the initial measurements were 0.1, the recheck were 0,5 (after making no adjustment) and I changed the shims to again read 0.1. So if they'll adjust after running they will end up at 0.15 which is still within spec.

    Next time this happen I'll leave them alone.

    Thanks for the input all!



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