I wish it was simple as a blocked pipe I've had the fuel pipes air pipes filter and carb apart and cleaned out the full lot whilst getting high on white spirit but done a good job of it nonetheless, and plenty of petrol, I hope its nothing electrical that will be a twat to find :/ doesn't seem to be overheating although it has smelt of a sort of melting/ burning rubber smell but it has always done it so maybe this could be something? But when it has been running I never seem to be able to tell where it is coming from???