Hi all. Just looking for some expert advice. I have a 1997 MXZ 670 and the needles and seats dont seem to be working correctly. If I let the sled sit overnight the machine gets flooded and I need to pull the plugs, clean them, clear the gas from the cylinders and start it up sometimes with allot of effort. Once its running its fine. I will be replacing these on the weekend. The strange thing is and I am not sure if its related, but the bottom end on take off seems to stubmle a bit until midrange. The top end was rebuilt about 200 miles ago. There is good compression in both cylinders. I am wondering if the needle/float settings or bad neeles would have anything to do with this. Funny thing is it doesnt happen until the engine is up to operating temperature. If I go out on it when the engine is a bit cold it doesnt stubmle and feels much more peppy in the low end.
Any help is appreciated!

I think you are on the right track with this problem already. It could be running better when cold because they need more fuel when cold. It's like running with the choke on a little through warm-up.

Agree with idooski, sounds like you are on the right track. Perhaps for the cost and considering the age it would be wise to replace both needle/seats and floats, carefully checking float level upon reassembly.
Check and make sure your fuel tank vent is clear, don't want any pressure in the tank.
Have a close look at the pulse line on the fuel pump, if the pump is leaking the line could be allowing excess fuel into the crankcase.