This is on my list of things to try. I'll buy a timing light as its a pretty good thing to have anyway! I'll see how the spark looks on each lead. I also have a mutimetre so I'm going to check resistance from the brass button on the inside of the dizzy cap to the spark plug terminal to ensure there is no break in the curcuit from cap to plug. I've got new points as well so I'll replace them the current ones look suspect. I'm using Bosch but I've heard the Champion plugs are having massive issues.