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  1. #1
    suck my wake's Avatar
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    How much to cut the Head?

    How much should you cut the head when you install the RR cam to gain compression back? Anybody know about this?


  2. #2
    Site Admin Green Hulk's Avatar
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    I wouldn't cut the head at all.

    The RR cam needs to be advanced to a point to where it achieves 135 PSI of compression. Once you advance it to that point it really comes alive.

  3. #3
    Quote Originally Posted by suck my wake View Post
    How much should you cut the head when you install the RR cam to gain compression back? Anybody know about this?
    Do not cut the head adjust the cam if you want 135 lbs comp otherwise you will have like 125 strait up. If you cut the head to compensate you will have piston to head clearance problems.
    Last edited by RXP6; 10-08-2007 at 11:33 AM.

  4. #4
    suck my wake's Avatar
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    Quote Originally Posted by Green Hulk View Post
    I wouldn't cut the head at all.

    The RR cam needs to be advanced to a point to where it achieves 135 PSI of compression. Once you advance it to that point it really comes alive.
    Yea but if you dont get 135psi you would need to cut the head right? At what psi is it still safe to use pump gas and when do you need to use race fuel?

  5. #5
    Site Admin Green Hulk's Avatar
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    Tom, if you can't get 135 PSI by adjusting the cam then you have a problem somewhere. 1 tooth off perhaps.

  6. #6
    Whats that whistling noise? jtskier11's Avatar
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    With the lift numbers I hear that cam has..... Plus a milled head. Id be worried about piston to valve clearance big time!

  7. #7
    suck my wake's Avatar
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    OK point taken,dont cut the head! I was basically asking if/what the spec would be to cut the head. I am not putting the cam in it, I am changing the head gasket(its leaking) and since the head is going to be off I just thought I would see if there would be any advantage to milling the head for a little more compression. Thanks for all the responses

  8. #8
    Site Admin Green Hulk's Avatar
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    Tom, you can cut it .010
    Be sure to use the Rotax Racing cam chain tensioner when you mill the head.

  9. #9
    Whats that whistling noise? jtskier11's Avatar
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    Quote Originally Posted by Green Hulk View Post
    Tom, you can cut it .010
    Be sure to use the Rotax Racing cam chain tensioner when you mill the head.
    Dam, what will that change the compression? Maybe .1-.2 difference???

  10. #10
    EZ Dock of Long Island Shibby1485's Avatar
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    with a stock head gasket, milled head, and Rude cam... my motor WAS a touch over 140psi...

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