Thanks guys. I will do the WD40 thing to get me through to the weekend and then pull the plug out and check it all over. Gap, seating the cap properly etc etc.
Maybe I am being a bit thick here, but I am not a great mechanic. Where does the HT lead route to. On a car it is the distributor, but where the feck does it go to on a bike? Generator? CDI? Never really looked when I've serviced the bike. Just unplgged, installed new sparks and plugged back up. I know I will find out if I trace it back from the plug. Is it difficult to install a new set of leads. Don't flame me! I am trying you know.