my old 2001 yz250f has just started fouling plugs. i didnt ride it for a while and when my did went to start it the other day it wouldnt go. we changed the plug and it ran fine. we took it for i ride and it was fine. then today we went to the track and when he went to start it it didnt run. so we changed plug and it was fine. why would the plug foul with one hour on it. could my dad be starting it wrong? he does give it a bit of throttle when he starts it ( old 2 stroke habbit) would this effect it? do you think there is any other reason why its doing this? when we took the old plug out the tip was black.