Here the situation. Bikes a GPX250 BTW. Cant tell you what revs and all that its doing as i only have a temp gauge connected. The bike will start when cold or colled down with full choke and blipping of the throttle. Now im not sure whether thats its saying its lean or rich because the extra fuel the choke gives it i get, but the opening of the throttle is a sympton of rich mixture. Well thats what i think? Then once it hot the idle will all of a sudden be sitting relatively high then drop and if i dont catch it and give it some revs its will cut out. Just makes that noise like it either has too much fuel or too little. (i cant tell between rich and lean mixture noises). Then i cant get it started again even with mixing around with the choke and throttle position, maybe i just a few splutters. But no starting until cold again. Also should note i adjusted the floats to 17mm (manual spec) exactly each making sure it wasnt pushing the spring of the needle down. Re-measured too so i dont think its that. One more thing is that it has no mufflers on it as ive just rebuilt the engine. Not totally but it had exploded and ive got it running. So this means my mixtures will have to be richer than usual but the floats shouldnt need adjusting should they to compensate? Also the bike revs out very nicely at the top of the rev range. Im guessing ive gotten it to about 7K maybe less and it sounds good with a crisp throttle response when blipping it. Its just that annoying problem when i leave to idle then the revs drop right down and its cuts out unless i catch it in time. So guys/gurls. What your explanation of the events im experiencing. P.S: Carbys have been fully cleaned and no gloged up jets and needles. Fresh fuel, Spark plugs arnt the newest. In fact im not sure of there age. and its cooling fine, not overheating (unlike my other bike). Thanks for any helps guys. Help bring my project along and getting closer to racing.