I have a 1996 Cbr900 it has 14k miles on it and i just previously bought it from a friend. When i first bought it he had someone work on it and they did not sync the carburetors back up so we sent it to a different shop and got that fixed. About 3 days later the bike would not crank again. It would foul a plug. So we took it back to the shop and they said it needed a new jet kit and the carburetors were disgusting. The carburetors were cleaned out and a new jet kit was installed. This was about 1 week ago. The bike was doing ok after being out of the shop. Now it takes awhile for it to get cranked up. Its like it is cold natured when its not that cold outside. I will push the start button before it will stay cranked about 10-20 times. Once its warmed up it runs great and you can turn it on and off on first crank with no problem. The guy i bought it from says it takes a few starts before it will stay cranked. Im afraid im going to get stuck somewhere and it not crank. It has new spark plugs. But it does have old gas in the tank. Prob from last summer. Is there any simple way i can fix this. Im also new to bikes. I believe it has a thing were you can turn the gas on and off. If the gas stays on all the time, would that cause it to do this?