Was riding my yamaha jog rr 50cc lc down the road and heard a very quiet ping and my bike cut out. A local bike shop was very unhelpful and said it may be the cylinder that has gone. The bike has very low compression is this true? And if so how hard is it to change the cylinder and piston on this bike? Any help or advice would be appriciated.

Has the spark plug come out?

No its still in the head

A few days before bike broke the airbox was full of petrol. I drained out float chamber and it was ok after that on another forum I saw a guy with similar problem and someone said it could be a faulty spark plug. So might give changing the plug ago tomorow.