I have a 2007 Yamaha WR450 which has about 25 hours on it, a few months old.

I have to have the choke turned on for it to start and run and Idle...no matter how warm it gets or how long i ride it, if i cut the choke off it will cut off, i have tried drainin the gas out and putting in new gas, i have tried turning the idle screw all the way as far as i could and it still will not help, the only way that it will run is with the choke on.

i recently changed the OIL and sparkplug and oil filter, just before this started happening, the oil level is fine and there is no oil leaking from the bike.

any suggestions would be greatly appreciated

Trey

At the first time you can remove and disassemble carburator and clean it with air compressor. When you assemble carburator you can get help from your manual book. If this not help you pleace write.

Also when you ride the bike how worck the engine is there some strange noise ?

Try checking the carb to engine rubber isn't leaking and sucking in air. Had a Vespa ciau years ago that did the same thing and it turned out to be that. You never know it may be that simple...

Liam