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  1. #1

    Jetting for bored 1200 with premix?

    Well as some of you know the last rebuild didnt go so hot. I got a new crank and im going to try this again. This time I'm going though the entire carb while I'm at it. It appears that the center piston wasn't getting any gas at all before it blew, which definetly didnt help with the center rod bering going.

    So anyway, this time I'm going to run premix. I also have the cylinders bored out to .75. What jetting would be recommended. Rich is good, even if it costs me a few mph.


  2. #2
    ph2ocraft's Avatar
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    I run Conrad's SLTX with

    Mag 148
    Cen 150
    PTO 142

    I'm bored to 85mm, Keihin's with a rec porting job, 91 octane domes and she runs saweeeeet. For your set up, this should leave you rich but as usual 75 yard sprints and watch your plugs and wash.

  3. #3
    sounds good. What do you have the screws set at?

  4. #4
    ph2ocraft's Avatar
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    If memory serves me right they are between 1/4 and 1/2 turn out from slightly seated. I have no high speed adjusters.

  5. #5
    Quote Originally Posted by ph2ocraft View Post
    I run Conrad's SLTX with

    Mag 148
    Cen 150
    PTO 142

    I'm bored to 85mm, Keihin's with a rec porting job, 91 octane domes and she runs saweeeeet. For your set up, this should leave you rich but as usual 75 yard sprints and watch your plugs and wash.
    I'm in the process of trying to get the carb back together. I'm thinking I should probably just get a rebuild kit. Anyone know who has a cheap / decent kit for the keihin?

  6. #6
    Rasta Mon Condoms We Be Jammin!!!!! TxVirageTx's Avatar
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    keihins

    i've gone thru countless carbs and never needed to replace anything other than a needle that was indented.get all the grey lines off that ski,i'm rebuild a slth700 that got bit from the green gunkus.going to premix i'd probably step the mids up tp 45's instead of 42's.and one up across the mains,from 140-142-135 to 142-145-138.lows set at 1 1/4 out,this is an unported ski??

  7. #7
    Its completely stock with the exception of being .75 over. My reeds are in pretty good shape, but maybe I'll take them off your hands. Any performance improvement over stock?

  8. #8
    Rasta Mon Condoms We Be Jammin!!!!! TxVirageTx's Avatar
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    reeds

    no mph gain,but the ski will be way snappier on the throttle and more fun to ride

  9. #9
    Ok, I got it pretty much all back together. I have a light premix in the tank right now, I believe something like 50/1. What ratio should I be running for complete premix?

  10. #10
    Click avatar for tech links/info, donation request K447's Avatar
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    Arrow Pre-mix fuel:oil ratios

    Quote Originally Posted by ryanbgb22 View Post
    ...I have a light premix in the tank right now, I believe something like 50/1.

    What ratio should I be running for complete premix?
    Break-in with oil pump operating - 50:1 in the fuel tank

    Break-in with pre-mix only - 32:1

    Normal operation with pre-mix only - 40:1

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