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Mikuni Triple Carb Troubles

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  • Mikuni Triple Carb Troubles

    Working on a 1996 SL 780. Last fall I rebuilt the top end and while I was at it threw in a rebuild kit for the carbs. I did buy a quality venom rebuild kit. After install and I couldn’t get it to start. Eventually determined it was a fuel pump as no fuel was getting to the carburetors. I’ve been working with it the past couple days. Finally, I have fuel and will start an idle under its own fuel

    Now I have a new problem…. The center carburetor high speed jet is dripping fuel at idle.
    I can physically see it just dripping fuel.

    Anybody ever experienced before? Do you think this is a pop off issue? Any suggestions? I pulled the needle and made sure to adjust it again to 3/4 turn out as stated in the Manuel. Still no change. Really hoping to not have to pull the carbs off this thing again lol. I will try to upload a video later today

  • #2
    Originally posted by Beernutz
    The only rebuild kits that members of this community will refer to as quality are OEM. Watcon sells a kit package that has everything you need for the Mikuni carbs on Fuji powered Polaris machines.

    Carburetor Rebuild kit for polaris fuji SBN38, covers all 3 carbs – Watcon
    From my understanding reading this forum and others , the venom brand is a well quality rebuild kit. The price difference Between a venom and Mikuni/watcon is 20$ (I ordered the venom because it shipped a week and half earlier).


    • #3
      Ill tell you from many years of 2 stroke experience. You really need genuine Mikuni rebuild kits. That is the only way to be sure. Use the genuine OEM rebuild kits, replace the needles and seats, and reset the HSN and LSN back to factory spec, rebuild the fuel pump, and use new plugs. That is your baseline to tune off of. If your carb is dripping fuel you probably have a worn, or stuck needle.


      • #4
        Sorry Pineapple, I've never heard of Venom brand. Genuine MIkuni is the only brand we in the Polaris section recommend.

        Destructive pretty much summed it up in that post above ^^^^^
        My ski says made in the U.S.A...... Can yours say that???


        • #5
          I put aftermarket keihin kids on my 750 sxi and tried to tune it. Never again. The money I saved in an aftermarket kit was negated by the time I wasted trying to deal with inconsistent carbs. Just be glad they are Mikunis, the Keihins cost $70 per carb and that doesn't include the fuel pump stuff.
          (2) 98 Pro 785 - 90 Superjet 650 (coffman exhaust, etc) - 95 750 SXI (R&D exhaust, ported, polished, etc)


          • #6
            Well I can tell you from trying all that are out the Mikuni ones are worth the money , however the last time I had my pro out I did have some carb problems and had to use a cheep kit in one carb
            Made in USA ! Assembled in Canada


            • #7
              After pulling the carbs back off looks like the center carb needle arm was bent. Causing it to dump fuel. Checked pop off pressure in all of the carbs. Put it back on the ski and the same
              thing happened. Going to assume that arm somehow got bent out again, to that I have no clue how.

              I’m going to bite the bullet and spend the money on a mikuni rebuild kit

              let’s hope and pray. I think my arm will fall off if I have to pull those carbs again !


              • #8
                Not sure how the needle arm could get bent?

                But the thing you want to make sure is they are level with the metering block. If they stick up, they will lift the needle and flood. Too low and it will not allow enough fuel in.
                My ski says made in the U.S.A...... Can yours say that???