So I left my bike under a tarp for three weeks while away on vacation and I came back to find that it no longer runs properly. The bike starts right up if it has been sitting for a few minutes, however driving more than a block down the road prompts backfiring, sputtering, hard starts, little power, and eventually stalling out. I'm thinking that the float valve on the left carb is stuck because when draining gas through that carb, it starts strong but then turns to a dribble- enough to idle but not run the bike? Also, driving it up and down the street in this condition fouled up the spark plugs, is that normal? I have tried sea-foam, spraying carb cleaner into different orifices of the carb (I am fairly inexperienced) and none of this seems to help. Could it be something other than the carburator? Help!