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Thread: Head milling

  1. #1
    HOSS's Avatar
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    Head milling

    `05 RXP How much can I safely cut off the head? Also how much before I need a different chain tensioner and which one. If I do need a chain tensioner do I need to upgrade rocker shaft from the `05? I have to oil jet done. Dyno Darrel just stopped in and he hasn`t decided on what valve he is going with. He owns and operates Cycle Dynamics down here in Kenner and loved the site. He tripped out on what some of the guys here are running. Funny thing is he runs and builds some of the fastest bikes down here from fuel on down and thinks we are crazy for running the speeds we do. So hats off guys from a pro. Head is going to Houma to Southland Machine for pressure test and work. He is gonna flow the head. He will be doing a stock flow then after valves for comparison. I`ll post. Exhaust has to flow 90% of intake. He`ll get better. I`ll be orderring valves from the store as soon as he has deffinatively decided.


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    shrabber's Avatar
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    Twenty thousandths. Thats the answer topic has been ran across multiple times and normally the term is decking the head.
    Last edited by shrabber; 05-16-2013 at 03:19 PM.

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    remove not more than .010 and use a different gaskets to get to where you want it. That's my recommendation anyway.

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    Pm slow 91

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    shrabber's Avatar
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    Quote Originally Posted by imp0ster View Post
    remove not more than .010 and use a different gaskets to get to where you want it. That's my recommendation anyway.
    Had a couple decked ten thousandths np oem seadoo head gasket. Personally I would not deck a head not worth the performance gain just skim it to a straight edge
    Last edited by shrabber; 05-16-2013 at 03:36 PM.

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    imp0ster's Avatar
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    I agree with the fly cut. On the GM 3.8 it gained 7whp per .010 removed. Quenched the inefficiency of the motor. I really can't see it doing shit on these motors besides removing material. Better off with higher comp pistons

  7. #7
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    Quote Originally Posted by shrabber View Post
    Twenty thousandths. Thats the answer topic has been ran across multiple times and normally the term is decking the head.
    Thanks for the reply. I have a f up from a dumb ace at another machine shop. Thats what I get for trying to help out. I have to skim the head to get flat without cutting into intake seats. Thats the prob. After then we measure to see if no more than 20! This isnt for power. Its to try and save a head. Also he flows at 10 inches then convert to 28. He noticed the stock head is flowing 210 on intake and 160 on exhaust. He says the intake stops and wont flow anymore. So, he will be leaving stock size intake valve and going bigger on exhaust. Decking a head? When thrying to get power, for quench, the common term in the hotrod community is clipping the head. No arguments from me, but I appreciate the info. Also what is to gain from the `06 timing tensioner? Thanks

  8. #8
    BTW, you might want to carefully check that the cam bore is not out of whack before investing in decking the head. And torque it down and check cam bore again after decking.

  9. #9
    Water4fire's Avatar
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    Quote Originally Posted by Sea Dood View Post
    BTW, you might want to carefully check that the cam bore is not out of whack before investing in decking the head. And torque it down and check cam bore again after decking.
    Yea, because I found out the hard way that they can warp internally and there is no fix.

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