The engine diagnostic light comes on after a few minutes running. I have just had a 5000miles service but I have checked the oil which looks fine just in case. If i stop the engine, turn the ignition off and then start again, the light goes off, at least for a while. The engine seems to behave and sound normally. I called my local HD to book a check up and they told me that this sometimes happen and that I shouldn't worry too much and that it was OK to ride. I'd hate to blow an engine or cause any damage to it. Are they right and what could be the cause of the trouble.