my bike has been sitting in the garage for about four years,i drained the carbs before storage and now i put new plugs fresh gas and it will idle good but when i get on it to ride it starts to cut back on me really bad and i have to rev it up to get it go once i put it in gear,so i took the plugs back out and they had a black flim on them that i could wipe out with me finger i check the plug gap and it was correct.can anyone help me