rmspence

I have a 1998 R1 which I bought 6 months ago with 6666 km on the clock. The bike now has 9300 km on the clock. Since I bought the bike, it had problems with cranking the motor, particularly if the petrol tank was full. It was as if something got stuck in the motor. I suspect a leaking petrol tap and also possible leaking needles and seats, with the result that petrol could be running through the inlet valves to the top of cylinders and causing a lack of space in the cylinders when cranking and hence the motor not turning. A few days ago, the motor did not crank and when it finally started, it did not want to idle and started to smoke a lot. Oil was running from the bottom fairing and I battle to start the motor cycle again. I suspect a bent valve(s) or broken rings causing the excessive smoking. Did anyone have similar problems or any suggestions? Is it necessary to close the tap at all instances, because it is located at a very ackward place under the tank and very difficult to reach if you have fairly big hands?