So I have this ski I've been sitting on for 4 years and finally putting in the effort on getting it to run perfect. It was rebuilt 3 years ago with SBT pistons 1mm over bore, have now run approx 25 gallons through it, most of it this year. Head is shaved .040 (that I know of as it's stamped on it), 150 psi per hole, stock exhaust, R&D intake with a SBN 44 mm mikuni (which I bought used and literally bolted it on with minimal tuning till now, I was told it came off a 750 but don't know for sure, seems like it could have been a factory Yamaha carb as it still has a choke plate) R&D timing advance. Out back I'm currently running a 9/17 skat trak big hub swirl, jet dynamics scoop and an extended ride plate.
Anywho it runs decent overall, except I seem to have an issue with it loading up at times. I should note I had to go to a BR9ES plug as a BR8 for whatever reasons I would get pre ignition on a hot motor and shear the key for the flywheel on startup, part of my problem. Goes ok with the br9 BUT on checking plugs they look cold. It gets shell v power and amsoil at 45:1.
My main jet is a 130, H screw turned in all the way. Pilot is a 112, screw at roughly 3/4 (seems very close for off the line starts it gets out of the water nice). Silver spring, unsure of needle and seat bore but it's in good shape and my pop off is set to 40 (seems high?)
ANY help would be greatly appreciated!! I plan on ordering a smaller main jet, but not sure if I need anything else??? I was running a Solas SC-I 14-19, but it felt like the motor was having trouble turning it, even though I could go 45 mph.. Since the timing advance went on it feels fat on acceleration, though I read that's normal.
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Anywho it runs decent overall, except I seem to have an issue with it loading up at times. I should note I had to go to a BR9ES plug as a BR8 for whatever reasons I would get pre ignition on a hot motor and shear the key for the flywheel on startup, part of my problem. Goes ok with the br9 BUT on checking plugs they look cold. It gets shell v power and amsoil at 45:1.
My main jet is a 130, H screw turned in all the way. Pilot is a 112, screw at roughly 3/4 (seems very close for off the line starts it gets out of the water nice). Silver spring, unsure of needle and seat bore but it's in good shape and my pop off is set to 40 (seems high?)
ANY help would be greatly appreciated!! I plan on ordering a smaller main jet, but not sure if I need anything else??? I was running a Solas SC-I 14-19, but it felt like the motor was having trouble turning it, even though I could go 45 mph.. Since the timing advance went on it feels fat on acceleration, though I read that's normal.
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