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  1. #1
    Ya Boy Trevor bajaeater's Avatar
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    jetting on gp1200

    hey got a 99 gp1200 bored 2 over with rec head. flame arrestors and boysen reeds. that should be just about everything. i need to know what jetting i should be running in this thing. looking to be on the safe side. thanks


  2. #2
    Mpeavler's Avatar
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    Quote Originally Posted by bajaeater View Post
    hey got a 99 gp1200 bored 2 over with rec head. flame arrestors and boysen reeds. that should be just about everything. i need to know what jetting i should be running in this thing. looking to be on the safe side. thanks


    I would go up a total of 4 jets on the highs.....and 2 on the lows and go from there. I would not run it more then 1 1/2 turn on the highs out without an increase in the main jet.

    M

  3. #3
    Moderator OsideBill's Avatar
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    On my 65U 1200 I run a 1.5 N&S, 115 gr Gold spring, 100 pilot jets, 135 main jets, chokes removed and dual fuel supply. The motor is bored .5mm over with 145 PSI head (91 oct) Boyesson pro reeds, R&D power plenum, 40:1 pre mix. I have run three seasons without so much as hic-up from this set-up.

  4. #4
    Mpeavler's Avatar
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    Quote Originally Posted by OsideBill View Post
    On my 65U 1200 I run a 1.5 N&S, 115 gr Gold spring, 100 pilot jets, 135 main jets, chokes removed and dual fuel supply. The motor is bored .5mm over with 145 PSI head (91 oct) Boyesson pro reeds, R&D power plenum, 40:1 pre mix. I have run three seasons without so much as hic-up from this set-up.


    What's that vs the stock jetting Bill?

    M

  5. #5
    Moderator OsideBill's Avatar
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    Stock Jetting was 1.2 N&S, Gold spring, (stagered low speed jets) 92.5, 95, 97.5 and 135 mains. Sorry I do not remember the turns on the adjuster screws.

  6. #6
    krispaintballz's Avatar
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    Here is the set up on how many turns for a stock 1200.
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  7. #7
    Ya Boy Trevor bajaeater's Avatar
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    right now it has 95 pilot jets and 135 main jets at about 2 turns out. it has no wash at all on the old pistons and keeps blowing the number 3 piston. riva said the crank may be twisted so im gunna check that tomorrow.
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  8. #8
    krispaintballz's Avatar
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    Almost kinda looks like a rear seal leak..........Are you always losing the piston near the exhaust port?

  9. #9
    Ya Boy Trevor bajaeater's Avatar
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    always losing the number 3. number 3 has blown 2 or three times all b4 break in. it isnt my ski. im just trying to fix it for him. shops up here dont like to mess with modded skis. they get overwhelmed lol.

  10. #10
    Moderator OsideBill's Avatar
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    is that a heat mark in the center of the piston? here is what mine looked like last time I pulled the head with the above jetting
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