My 03 XLT 1200 was running fine. After riding it a while it wouldnt go above 40mph or so. It was hit and miss for a while between running fine and topping at 40. Now it just wont go above 40. tried seafoam in the gas and put a new set of plugs in it and no change. checked and made sure there wasnt anything in the impeller. seemed clear. any ideas? thanks in advance.