peasie Posted March 23, 2011 Report Share Posted March 23, 2011 Hi there anyone know the correct setting for the air mixture screw on a txt 280 2001 carb as mine isn't running right backfires alot. All info will be greatly recieved thanks,(i did a search and couldn't find much) Steve Quote Link to comment Share on other sites More sharing options...
wingandaprayer Posted March 23, 2011 Report Share Posted March 23, 2011 Hi, try 1 1/2 - 1 3/4 turns out on mixture screw. cheers Quote Link to comment Share on other sites More sharing options...
jam Posted March 23, 2011 Report Share Posted March 23, 2011 (edited) On the GG std carbs its a fuel screw and they recommend 3 1/4 - 3 1/2 turns out with a tick over and it should run sweet. Edited March 23, 2011 by jam Quote Link to comment Share on other sites More sharing options...
peasie Posted March 25, 2011 Author Report Share Posted March 25, 2011 On the GG std carbs its a fuel screw and they recommend 3 1/4 - 3 1/2 turns out with a tick over and it should run sweet. Thanks for the replies,but i'm a bit confused now there are 2 screw settings on my carb i guess 1 = tickover and the other is a smaller screw which i would say is the mixture,so from fully wound in (closed) how many turns out is correct for the mixture? Many Thanks again sorry if i have just confused matters Quote Link to comment Share on other sites More sharing options...
jse Posted March 25, 2011 Report Share Posted March 25, 2011 Thanks for the replies,but i'm a bit confused now there are 2 screw settings on my carb i guess 1 = tickover and the other is a smaller screw which i would say is the mixture,so from fully wound in (closed) how many turns out is correct for the mixture? Many Thanks again sorry if i have just confused matters The screw in the center of the carb body adjusts the slide stop and is to set the tickover speed. Be sure to adjust the tickover with the engine warm, bike in gear and the clutch pulled back normally, which is usually with one finger back to the knuckles (not fully back to the grip). This way you adjust for clutch drag and reduce stalling. The other screw is to fine-tune the off-idle response (a "mixture screw" in this case) and there is no absolute correct setting for it, in spite of what some may tell you (that's why it's adjustable and not factory set). The mentioned settings are a starting point only and that screw is used to adjust the carb response under changing ambient weather conditions (the off-idle throttle response is a complicated "proceedure" and there are several "circuits" that have an influence on it and they all overlap). Once you get the hang of it, it's fairly easy to do. First, very lightly bottom out the screw (screwing it in hard will damage the needle and seat). Turn it out about 3 turns, the number of turns is not critical, you could start with 2, for instance. With the engine warm and in neutral, quickly open and close the throttle ("blip it" as we say in the States) and then adjust the screw in or out to start. When you go too far either way, the engine will start to bog so then you go back the other way until the engine responds perfectly. That is the "correct" setting. The "recommended" number of turns-out for the mixture screw will work well in most cases (but not all engines) but if you want your engine to run it's best under a variety of conditions, you'll take the 30 seconds now and then it takes to check the mixture setting. Unlike the other forms of motorcycle sport, Trials riding places a huge demand on the carb's ability to constantly adjust the air/fuel ratio in the idle-to-half throttle range. Jon Quote Link to comment Share on other sites More sharing options...
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