Kramer3 Posted July 7, 2017 Report Share Posted July 7, 2017 I built this motor a little over a year ago, it's a 66.5mm piston, trail ported engine with PJ34mm Keilin carbs, Vforce 3 reeds,stock bottom end. I am running a 150 main and have a little bit of a bog in 1st and 2nd gear if you get on the throttle pretty quick. I have the air screws out 1 1/2 turns right now and I'm not sure what to do to get the little bit of bog out of it. If you roll into it, it is not that bad. I'm trying to get a little advice on fine tuning the carbs. I'm not sure if I should mess with the air screws more or change my jets and which way if I do. Quote Link to comment Share on other sites More sharing options...
Ayesully810 Posted July 7, 2017 Report Share Posted July 7, 2017 What is your pilot jet and what needle are you running and at what clip? Quote Link to comment Share on other sites More sharing options...
JUSTWANNARACE Posted July 8, 2017 Report Share Posted July 8, 2017 13 hours ago, Kramer3 said: I built this motor a little over a year ago, it's a 66.5mm piston, trail ported engine with PJ34mm Keilin carbs, Vforce 3 reeds,stock bottom end. I am running a 150 main and have a little bit of a bog in 1st and 2nd gear if you get on the throttle pretty quick. I have the air screws out 1 1/2 turns right now and I'm not sure what to do to get the little bit of bog out of it. If you roll into it, it is not that bad. I'm trying to get a little advice on fine tuning the carbs. I'm not sure if I should mess with the air screws more or change my jets and which way if I do. Go up on the pilot jet if it's happening when you hit the throttle. To much air not enough fuel on the transition from the pilot circuit to the needle and main..jmo Quote Link to comment Share on other sites More sharing options...
Keno Posted July 8, 2017 Report Share Posted July 8, 2017 https://www.duncanracing.com/TechCenter/KeihinCarbJetting.pdf Read this, it should help you understand what changes do what. Especially the use of the air screw. I keep a copy with my boxes of jets Quote Link to comment Share on other sites More sharing options...
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