350BANSHEE350 Posted August 15, 2007 Report Posted August 15, 2007 ok this is what i think it does it controls the amount of gas let to the main jet so the more turns out on the air screw the more gas it gets making it richer and vis versa? please dont make fun of me lol i have no clue somebody please explain in full detail Quote
Snopczynski Posted August 15, 2007 Report Posted August 15, 2007 Well on stock carbs, it lets in more or less air, hence "Air Screw". So screwing it in decreases the amount of air at idle, screwing it out increases the amount of air at idle. It does this on 95% off small engine carbs. I think there are a few carb types that increase or decrease fuel via the screws on some snowmobiles and watercraft. Quote
fox_forma Posted August 16, 2007 Report Posted August 16, 2007 correct me if I'm wrong but the pilot jet and air screw has nothing to do with the main jet fuel supply. It controls the start up of your shee. I guess the air screw could effect the main a little but not anything drastic. Mostly for starting your bike is what the pilot and a/f screw controls. your needle position and main is what gives you the power. Quote
dajogejr Posted August 16, 2007 Report Posted August 16, 2007 All of the jetting circuits blend to a certain point. The air screw/pilot jet have no effect on the main. Here's how it really works.... If the adjustment screw is before the carb venturi (airbox/filter side) it's an air screw. Out means more air, in means less. If the screw is in front of the venturi, it's a fuel screw. Same thing...out is more fuel, in is less. Some of the 4 pokes have fuel screws instead of air screws....it's a lot more than 5% Snop... My buddies Honda with and FCR has a fuel screw.... 350...on top of this forum there are some very, very helpful stickies on how carbs work and jetting. I'd bet they'd answer 95% of your questions....and are an invaluable learning/reference tool... Take a gander!! Quote
Snopczynski Posted August 16, 2007 Report Posted August 16, 2007 Its not as common as you would think, but most of those fuel screw carbs are 4 stroke units with accelerator pumps in them. Quote
dajogejr Posted August 16, 2007 Report Posted August 16, 2007 Its not as common as you would think, but most of those fuel screw carbs are 4 stroke units with accelerator pumps in them. Yeah...those accelerator pumps play hell jetting those four strokes, damn near makes it impossible to read a plug!!! Quote
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