YZ 400 won't run

I have a YZ400 and it used to ride fine before the winter, I stored it incorrectly and now it won't run. I cleaned the carb and it would fire up but when ran it would always stall, and when it would run it would back fire alot when the throttle was put on steady. So I sent the carb in again to have it cleaned and they "reset the carb to stock", and now I can't even get it to start. Before it was reset the clip was way on the rich side, and the fuel screw was about 1 3/4" turns out. When running it would get hot reallly fast, and would only run on the choke, so I turned out the fuel screw 1/4 turn but nothing realy changed. The valves are in spec, and has a new plug. I am trying to sell the bike but want it to to run right before it sells.

I hate to tell you to do this for a third time but that carb still aint clean . My guess is that the main jet and the needle jet still have lots old gas goo on and in them . You should be able to do this on your own with a few tools and can of carb cleaner . Just lay out the parts in the order that you removed them (no need to remove the slide , pull the needle through the top ). Dont know if I'd bring it back to the dude that "reset the carb to stock" though .

Side note ; do you have fresh gas in the tank ? If it smells funky it needs to be dumped and replaced . Dont fret , I worked on bikes for a living in a previous life and have had to clean the same carb twice on more than one occasion !

You watchin' my back grayracer ?

did you take the slide out? I don't remember the carb that well on my 400 but if the carb is similar to your 03250f, then you may have put the slide plate in upside down which gives identical symptoms to what you described. If the carbs are similar, look down the throat of carb from engine side and you should see a small hole at bottom of slider. If not then the slide plate is upside down. Easy to do wrong and easy to fix.

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