JCSO605 Posted March 9, 2014 Report Share Posted March 9, 2014 I'm new to alky bought a set of alky 39.5 mikunis to run on my 10 mil cub from a member The carbs are tube drilled to 116 pilot is 60. The bike will not idle at all have to give it some throttle to keep it running and it seemed to be flooded with fuel. Fuel pooring from the front exhaust flanges . Took carbs apart and found they had a 230 main jet. Can anyone get me close to where I need to be with the jetting. I'm at 100 to 300ft asl. 80 degrees 176lbs compression + 10 timing. Thanks. Quote Link to comment Share on other sites More sharing options...
JCSO605 Posted March 10, 2014 Author Report Share Posted March 10, 2014 Anyone? Quote Link to comment Share on other sites More sharing options...
n2otoofast4u Posted March 10, 2014 Report Share Posted March 10, 2014 60 pilot seems big Quote Link to comment Share on other sites More sharing options...
Surfrjag Posted March 10, 2014 Report Share Posted March 10, 2014 Are they gravity or pump? Quote Link to comment Share on other sites More sharing options...
JCSO605 Posted March 10, 2014 Author Report Share Posted March 10, 2014 Idk where to start. I guess 55 pilots. Idk where to start with methanol. Quote Link to comment Share on other sites More sharing options...
JCSO605 Posted March 10, 2014 Author Report Share Posted March 10, 2014 They are gravity. 38 mikuni flat sides bored to 39.5. Quote Link to comment Share on other sites More sharing options...
JCSO605 Posted March 10, 2014 Author Report Share Posted March 10, 2014 I'm having to give it throttle to crank it and hold it to keep it idling I'm about to throw my gas carbs back on Just getting frustrated. Quote Link to comment Share on other sites More sharing options...
RadarRacing Posted March 12, 2014 Report Share Posted March 12, 2014 Ok, What I am talking about here is only when starting the bike NOT riding it. As far as the mainjets completely disregard what number is on them. They are probably drilled larger than whats stamped on them. They are probably closer to a size 300-380. If it is blowing alky out the pipes when you try to rev it off idle then lean the needles out. Sounds like you need to lean them out quite a bit. If you get better but not perfect go down a size or two smaller on mainjet. (smaller compared to numbered drill bits NOT stamped number) and try it. When you go to a smaller mainjet you might want to richen the needle back up to check when you start it so it isnt too lean. In my opinion you arent going to hurt anything by starting and revving the bike with it a bit lean unless it screams and blows. If it is lean it will idle cray high and free rev at like 10,000 rpms. To stop it either jam it in gear with the rear brake on or crack the throttle open quickly to kill it. Heres my chart on needle setting If it blows CLEAR COLD WET alky on your hand ITS RICH If it blows SOMEWHAT BROWNISH, COLD alky on your hand it is RICH BUT CLOSE IF it blows VERY WARM, BROWN SPECKLED exhaust on your hand. ITS JUST RIGHT You will notice much better throttle response with the needles set correctly. Then turn the powerjets wide open to start hard throttle passes and lean down the PJs as needed. I hope that helps and keeps you safely from out of tune to good. Radar 1 Quote Link to comment Share on other sites More sharing options...
JCSO605 Posted March 12, 2014 Author Report Share Posted March 12, 2014 Thank you radar racing Quote Link to comment Share on other sites More sharing options...
registered user Posted March 12, 2014 Report Share Posted March 12, 2014 i like mine to idle around 2500rpm or so. sounds like you might need a few pilots and needles to try. i never used a mikuni so i dont know what else to say Quote Link to comment Share on other sites More sharing options...
Empire Industries Posted March 12, 2014 Report Share Posted March 12, 2014 Drill Main jet and emulsion tube to .118 Use 6FJ41 needle in 4th clip position. 35 to 45 pilot . Start big n work ur way down. Probably end up around 35 to get it crisp off the bottom. Power jets should be drilled to .092 . When making a pass ,start with the power jets wide open. After making a pass reach down and feel the side of the cylinder . It should be warm enough that you can put your hand on the cylinder for 3-4 seconds before pulling your hand off .It should not be as hot as a gas bike. If you can leave your hand on the cylinder longer than 4-5 seconds it's rich . Turn the power jets in 1/2 turn at a time until it builds some heat. Hope this helps Quote Link to comment Share on other sites More sharing options...
BANSHEE HP Posted March 12, 2014 Report Share Posted March 12, 2014 I run a 55 pilot in my 4mm cub and 60 in my 10mm cub. 116 in the 4mm and 119 in the 10mm. Are/have you adjusted the slide adjustment screws? Air screws? Quote Link to comment Share on other sites More sharing options...
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