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  1. #1
    flyboy's Avatar
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    BAD casting on R&D heads

    checked my compression before I had my heads taken down a bit

    #1 145
    #2 147
    #3 150

    I just thought this was a difference in the cylinders or what not. Well, the difference is in the poor casting job done by R&D.

    Had .02 taken off and

    #1 has a lip
    #2 has a smaller lip
    #3 has no lip

    the difference in the compression was comming fron the heads. I switched heads 2 and 3 so now 2 has no lip, and 3 has a small lip, then I had #1 taken down to match 2. I'll find out the results tomorrow.

    Basically check your R&D heads...

    James


  2. #2
    mtrager's Avatar
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    Switch one and three and Ride it Dirty.

  3. #3
    r33pwrd's Avatar
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    rivas heads look like crap too!

  4. #4

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    Switching #1 with #3 would have been a good idea since the #3 is prone to detonation (crank twisting and all of that). Having less compression on #3 could have been a potential benefit.

  5. #5
    txgp1300r's Avatar
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    as long as its the head with the bosses , if the low comp head is the smooth top one ,which is no.1 ,you will need to cut, i just went through this. my riva heads looked real good and milled perfect,no poroscopy or any flaws in the metal... chucked them up in the ol claussen lathe and gave them a haircut..

  6. #6
    Moderator RX951's Avatar
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    Quote Originally Posted by mtrager
    Switch one and three and Ride it Dirty.

    yup...I would agree. keep the lower compression on #3.

    I dont' think you can put the #1 head because it doesn't have the pipe mount bosses.
    147 is safer than 150 for #3.

    Thanks for sharing that James. Good idea for everyone to inspect their aftermarket heads.

  7. #7
    TX21's Avatar
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    Can you run reg. pump gas (93 octane) with 150 psi? I have a stock set-up and am awitching to some heads that have more compression. Stock I get 119 120 120 don't have he after market numbers yet. Just curious what the safest set-up is.

    edit : Holy crap I just noticed this thread is a mummy sorry.
    Last edited by TX21; 06-08-2007 at 09:25 AM.

  8. #8
    Moderator OsideBill's Avatar
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    Quote Originally Posted by TX21 View Post
    Can you run reg. pump gas (93 octane) with 150 psi? I have a stock set-up and am awitching to some heads that have more compression. Stock I get 119 120 120 don't have he after market numbers yet. Just curious what the safest set-up is.

    edit : Holy crap I just noticed this threak is a mummy sorry.
    I run 91 octane here in Cali with 150 PSI heads

  9. #9
    TX21's Avatar
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    Quote Originally Posted by osidebill View Post
    I run 91 octane here in Cali with 150 PSI heads
    Cool thats what I was thinking.

  10. #10
    HopatcongGPR's Avatar
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    thats why they are suppose to be cc'd prior to cutting. the material they use for casting is also crap. some crack some dont. if you drill holes in an old r&d head to verify casting thickness you would puke when you saw the delt in thickness with those castings.....hence why i will only use the one piece protec head IF i am using an aftermarket head. the protec head is a work of art imho.

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