Hoping someone can answer this question. Does a coil fail completely or does it gradually stop working. This is why i ask, on a recent tour my bike failed to start, i was about 3k into a tour. We pulled the sparkplug and the spark was weak, i tried my new spark plug and it was weak also. Someone suggested it might be an ebay fake, so another member of the group had a 10k plus old plug which we tried and got a better spark. we fitted this and it got me all the way home another 2k without mishap. Starting the winter stripdown now i am back home and looking for advice on best way to proceed. bike is a xt660z 09 my