dogbone

I have a 2002, it has about 20 hours on it. When i bought it it ran great. I put pro cerciut pipes and silencer. new carbin fiber reeds. I am running 260 main jets. the problem is it runs fat on top, it is like the choke is stuck but it is not. I have changed carbs, changed cdi, stater, plugs every part of the ignition has been changed a friend of mine has a 2002 that rus great. so i took parts off of his and put them on mine. I have thought of just about every think i can think of. all of the easy stuff. It is getting oil in the cylinders, and buy oil i mean case oil, the thing is, i dont know how it could i mean if the crank seal was bad, on the right side how could it get in both heads it is getting about the same amount in each. I thought of a hole in the case but that would make it run lean not rich. it runs grat at an adol and about half throttle then it runs like it is cold and wont clean out. we changed throttle cable. i mean we changed every thing. i made sure the tank was getting air vent tube pluged that sort of thing, every thing is fine does any buddy know how or if you can preasure test the case to see maybe if i can find a leak. the yamaha dealer said we can fix it. i said ya for about 500 bucks in labor. not i have spent 300 in laber at three differnt bike shops and nobuddy can seam to find it. every one just checks the same thing. it must be in side the motor but what please help, any heard a such a problem.

I run mixed gas in the wifes honda accord all the time been doing it for years. it does smoke a little but not very much it wont do a thing to it. just dump it in a run it!