I have a 2002 YZ426F. If I let it sit for like 2 weeks without running it, I will not be able to start it without replacing the plug and kicking it numerous times. The plug is fuel fouled and wet when I pull it. Even after replacing with a new plug, it is still a fight to get it cranked. However once it cranks, I can ride all day and never have trouble cranking it again or with it running poorly. I do turn off the fuel, but I have not been running it out of gas or draining the bowl on carb. I never had problems like this with any of my other bikes. Two weeks does not seem long enough for the gas to evaporate out of the bowl, but my next step will be to start draining the carb before storing. Any other ideas?