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  1. #1

    Big-Bore head for your over-bored gp1200r or gp1300r

    As the title says. I bought this head for my gp1200r but it's been worked over for much larger displacement craft. The stock head measures 81mm from ridge to ridge. This one measures in at 89.25mm. From the looks of it, this head is in excellent condition. By my crude calculation the stock head is 45cc. This one is measuring at about 55cc. With your big bore jugs this should get you going well. I have no idea what your compression numbers would be unless there's a calc somewhere around.

    I bought this this head for my stock gp12r but lost compression from it. Engine actually ran fine just down on power. Just pulled it and can't believe this head is for a bore up to 10% larger than stock. I was told that Lowell porting cut this head but since I bought it used I'm really not sure. Honestly for the longest time I thought my engine had a little bit low compression (80psi) and it was this head.

    Now, this head would probably go awesomely with a big bore gp motor.

    I took a micrometer to the largest wide cut, 89.25mm. The stock gp1200r head is 81mm.
    Cc measurement was with a measuring syringe and water with a plug upside down.

    I pictured a stock head next to the one I'm selling.

    $120 with water cover shipped to lower 48 paypal
    [email protected]
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    Last edited by ZeroClient; 12-24-2013 at 06:43 PM.


  2. #2
    Heres a close-up shot of all three domes
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  3. #3
    Bump. Any questions from anyone?

  4. #4
    Bump. Is no one going big bore this winter?

  5. #5

  6. #6
    $110 and I'll include whatever non metal gaskets you may need for your ski.
    Last edited by ZeroClient; 08-22-2014 at 10:00 AM.

  7. #7
    I'm kinda surprised I'm not getting offers on this piece. On any case, I'll let this ad drop down the line. If anyone needs this send me a pm in the future.

  8. #8
    I just talked with Lowell Horning on the phone about this head. This head is stamped LH9 and was custom built for 'Woody's engine; who ran 89mm bore and 3mm stroke (1512cc). This head was worked once or twice by Osidebill, twice because the compression may have been too high the first round.

    Lowell said this head will really only work on this engine. If anyone knows where Woody's engine is now - maybe it can be re-united with this head?
    Last edited by ZeroClient; 02-19-2014 at 03:17 PM.

  9. #9

    Join Date
    Jun 2007
    Location
    RANDLEMAN NC
    Posts
    7
    Interested in the head lmk if u still have it

  10. #10
    PM'd you back with a reply (Sorry it took an extra few days but I am available today to ship)

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