I have a Bet and Win 250 that is acting strange in that I fill the tank with gas go for a ride and when I try to start it the following day it will not start unless I top up the tank again. I had I full tank and went for 50 km ride and as I was coming home the engine day. I was near a gas station and put a small amount of fuel and I was able to get home. Today it would not start unless I put in a small amount of gas. What could be wrong - also the gas gauge does not work