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  1. #1
    Water Bum Rodneyae's Avatar
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    Fuel ?'s for sl750

    Ok I am ready to order my pistons for my 750 jugs. I am going with the Wiseco kit 1.75 oversize. Having gone from a displacment of 650 cc to a new displacmet of 783 cc's. I am going to need to do something about additionl fuel. What kind of suggestions dose everyone have. The stock 650 settings are perfect for the 650. Should I rejet the carbs? what size jets? Stiffer spring and raise the fuel pressure? Any other idea's?

    Thanks,
    Rodney


  2. #2
    ph2ocraft's Avatar
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    I would start with the jetting of the 780 and work my way down if needed. Be sure to go into the new tech section and grab the tuning tip guides so you can get a handle on things.
    The most important thing are short wide open throttle bursts and check the plugs and make sure you are NOT lean.

  3. #3
    cheatin' piston popper addicted's Avatar
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    And make sure that the machine shop bores the correct clearance for the weisco's, and that you warm it up. Those slugs are different than regular cast pistons.

  4. #4
    ph2ocraft's Avatar
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    Good point addicted, I've been running my Wiseco's on the SLTX for years with no issue what-so-ever.
    It just requires a few minutes for warm up and the proper clearance during the original build. I think I even went a little looser than Wiseco spec.

  5. #5
    BigDaddyPT's Avatar
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    how do you warm up wiesco pistons?

  6. #6
    ph2ocraft's Avatar
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    It's really just a matter of warming up the entire engine. The Wiseco's expand just a little quicker than the metals around it so they will seize to the cylinders if warmed up to quickly. I run mine from the 5 zone to open water which is roughly 5 miuntes, I've never seized it with that warm up.

  7. #7
    cheatin' piston popper addicted's Avatar
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    Basically, warm it up like you are supposed to do on any engine. Run it gently for a few minutes so that everything can get to operating temp, and expand into it's "running" size.

    Don't just start it up and rip across the lake at full throttle

  8. #8
    BigDaddyPT's Avatar
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    oh ok, so don't start it and go full throttle right away.

  9. #9
    gorilla03's Avatar
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    Quote Originally Posted by BigDaddyPT View Post
    oh ok, so don't start it and go full throttle right away.
    that's a good rule of thumb with any 2 stroke....if i remember right it's called cold siezieng....

  10. #10
    Water Bum Rodneyae's Avatar
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    Yes I know that! I use forged pistons in everything that I rebuild. But thanks. Dose any one have a set of 780 jets that I can purchase?

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