I pulled my LT250 out of the corner of the garage after it has been sitting for the last 6 months or so. It still has the old gas in it from the last trip (August 2002). The thing fired right up, but after taking a run or two down the street thick white smoke was spewing out the pipe. Is this just because of the old gas? Do I have a leaking head gasket? Or do I just need to tune the carb.

The bike is all stock, except for the slight bore when it needed a new piston. (This has been done twice.)

I just remember that I forgot the take the choke of after getting it warmed up. Could this be the cause of the white smoke?

Yeah that is your problem the chock was left on. Run the thing up and down the street a few times to get all the oil out of the cylinder and change your gas. If the smoke is still there after 5 of 10 min of running then you may have blown the head gasket. You may want to check your coolant level just to make sure.

probably depends on the mix you had in it originally, get the choke off, run the bike again up and down the street and it should go away, if not could be the head gasket and then what you are seeing is steam. Then check the radiator water level if it has gone down a lot, get your check book out. But if it was running good when you put your bike to sleep it ain't gonna blow a head gasket while it's sleeping.
Now somebody answer my 125 suckyzuki question!!!

WELL, I HAD A CHANCE TO MESS WITH IT DURING MY LUNCH. I RODE AROUND WITH THE CHOKE OFF, AND IT WAS JUST AS BAD. I GUESS THE NEXT STEP IS THE GAS. IS THERE A WAY, BY LOOKING AT THE PLUG FOR EXAMPLE, TO DETERMINE IF THERE IS A PROBLEM THAT IS CARB RELATED.

did you check the coolant level? white smoke typically indicates water, as oil burns blue. a head gasket can corrode in storage and casue a leak just from sitting. have seen it happen many times.

I TOOK A LOOK AT THE COOLANT, AND IT SEEMS TO BE FINE. THERE IS NOT ANY SIGNS OF IT BEING CONSUMED BY THE PISTON VIA A BAD HEAD GASKET.

White smoke=Bad gasoline.

Could be gear oil leaking in from the clutch side. That makes white smoke, Ive seen it. But I would definately get some fresh gas in there first.