Hello and thank you in advance for any information from experience... I have read about 20 yz250f articles on erratic idle and hard starting yet no one has said they have fixed it. It seems to occur on the 01-05 yz250f's and i have read a ton of advice. Here is what is wrong and what i have done... The Bike is very difficult to start. Most of the time it takes bump starting and when it runs it either is normal idle but if i dont increase the throttle super slow it will bog and stall. or if i get the throttle going it then sits at a fairly high idle where it revs and responds fine but sounds at half throttle. Also the odd time i take the spark plug out it is wet so fuel is making its way in. Valves are well within spec ( I have tried to get them as far from tight as possible without making them loose) replaced cam chain as well Vacuum leaks, I have been told vaccum leaks can cause this and i have double and triple checked the intake and carburetor. The carburetor I have cleaned every inch of it and yes i put the slide on the right way. I even took apart the center section and the gasket looked fine. I then took another carb and stuck it on with no such better luck so Im pretty sure we can rule out the carby. I ran the standard tests in the manual for checking electrical problems and all were within spec. Spark looks good, timing is as close as one can get has anyone solved this kind of issue????