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  1. #1

    Almost ready to crank it up..new SBT motor

    1995 Kawasaki 750sts, engine is in, I have converted to premix, and I am ready to fuel, but two issues..
    The manual says back out the high speed screw 3/4 of a turn, SBT says 1 and and a quarter turn. I am ok with starting way rich, but on this ski it looks impossible to adjust the mixture screws for tuning without dismounting the carbs from their base... What a pain, is there a trick for the carb with the adjustments screws jammed into the other carb? tubing over the screws?

    Also, what octane gas should I use? This is Texas and its hotternhell right now.
    thanks


  2. #2
    Ask SBT if that setting is just during the break in period. They told me to mix my gas/oil at 40 to 1 while everyone else told me it should be 50 to 1.

    I called SBT back and they said that 40 to 1 was for the break in period for the first tank only.

  3. #3
    Pain is fear leaving your body.... rlovebk's Avatar
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    When its hot out, premium is good. But I would only use 87 during break-in.
    I can adjust mine using a side driver. Its a Husky with a 90 deg. bend about 1/2" long.

    RIVER RAT those pre-mix #'s look fine if your running injection. for full pre-mix better be 20-32 to 1

  4. #4
    Quote Originally Posted by RiverRatKow View Post
    Ask SBT if that setting is just during the break in period. They told me to mix my gas/oil at 40 to 1 while everyone else told me it should be 50 to 1.

    I called SBT back and they said that 40 to 1 was for the break in period for the first tank only.
    Well, thanks for the input, the break in instructions on SBT's site say 32:1 for start up, then 40:1 after; Now SBT is saying 40:1 (premix) to start with due to advances in oil, then stay with 40:1 as a safety margin, even though the engines are good at 50:1.

    Octane: SBT says higher octane is a safety margin, will only help, never hurt, which is consistent with what I have always heard (along with if you dont need it it is a waste of money).

    Carb screws, High speed: they want them out further than stock, pistons are now bigger, and perhaps too rich is better than too lean.

  5. #5
    Pain is fear leaving your body.... rlovebk's Avatar
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    Too rich is always safer for sure.
    High octane is NOT a safety measure. It is a possible detonation causation.
    An engineer that I trust (works with pwc's) says in hot weather its okay. I see you lurk at the Polaris section. Those guys have the same opinion I got from the engineer guy. Just an opinion but I trust the Polaris guys and the eng. guy should be in the know.
    I'm surprised the mix ratio is so high. I just broke my SLT in @ 40-1 WITH oil injection still working.
    I would go with what SBT tells you though. Their warranty. You do what they say, then they always would have to honor it.
    Good luck!!!
    Been out on the water alot this year already and am really enjoying it. I joined the AWA and the SoCal guys are a great bunch to ride with.
    Good people, good fun!

  6. #6
    Thanks for the reply. SBT's tech person said premium gas was a good safeguard against detonation, and there was no downside to it, which agrees with everything I have heard. I have never heard of a reason, or how, a higher grade/octane gas would cause a problem. In fact, i am picking up off of some of my old motorcycle forums that higher octane gas tends to sit better with stabilizers added over the winter, since the octane value of all gas degrades in storage, so starting with a higher number (premium) has better results in the spring. However, I am new to pwc's and if there is a reason against premium I would love to hear it! thanks for the post.

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