When I am at near idle on my o6 KXf450, then snap to full throttle the bike stalls. At quarter to full, the bike runs fine.

Ok, so there are 2 adjustment needles on the carburetor. A H and an L... If your saw is idling fine you won't have to worry about adjusting the L needle.

Your focus will be on the H... the high.

Firstly, if there is any plastic covers on the adjustment needles, remove them. Usually red and white in color... or just white. They serve no purpose(EPA regulations for California). Now adjustart in quarter turn increments.. turn the screw to the right until snug, now back it out 1 full turn. This is your starting point. While holding the trigger all the way in, turn the needle counter clockwise in quarter turn increments, use your ear to tell when you have peak performance.

If you can't hold it down cause it bogs out, just hold it in as much as you can while you turn the needle until you can fully depress the trigger all the way

Brad:

Go back to the carburetor adjustment screws and snug them down gently. Do not use force on those screws or you'll damage the needle valve seats. Turn both screws out one and a quarter turns out and start the saw. The motor should stay running.... if not adjust the screws until it stays running. Turn one screw in until you hear the motor start to stall, then turn that screw out just a little bit. turn the other screw in until the saw starts to stall, then turn that screw out a little bit. Now if the saw bogs at full throttle, turn one screw out one quarter turn. See if the saw runs at full throttle... if not turn that same screw in to where it was and try the other screw the same way. If you're good, you can adjust the screw while the saw is running to get the best full throttle run. This is not an exact science, and it takes time and many adjustments to get the saw to idle and run at full throttle. Good luck... and have patience.

Try changing the spark plug first and clean the air filter.

give your bike to any good mechanic.it maybe some engine tuning problem not in carburetor

If you haven't already adjusted the carb there are usually 3 adjustments. H - adusts performance at full throttle (how it cuts in the wood). L - adjusts performance at idle and accelleration to full throttle.It sounds as though those are fine. The third adjustment T - is the throttle or idle speed (often away from the other 2). If my saw that is the one adjustment I'd make. You supplied no make or model, it is difficult to provide what you requested without them. HTH
Lou

some carbs are not adjustable,check your air filter first to make sure its not rescricted and also a new plug,make sure your fuel is fresh,now if you do have adjusting screws,most have plastic caps on them with preset adjustments locked in,you will have to remove these caps to adjust,they need not be reinstalled,Hope this helps

The Choke may be stuck or left on.

The main jet need cleaning.(you should clean them all though)

Main Jet: Main jet comes into play at three-quarters open to full throttle conditions. CRITICAL to high-speed engine operation. Not only does it meter the gas into the engine, it can aid in cooling the engine as well.

Please rate this Fixya

u have the mixture screw wound in to far. its normally located on the bottom of the carb. try winding it out half a turn at a time once the bike has warmed up. also turn the idle screw out a quarter of a turn at the time its in to far thats why it idles at low revs. the choke is needed to keep the air fuel mixture right thats why u are having to leave it on for so long. hope this helps.

check your transmission fluid,the motor will stall when fluid is low