Not all the time, I diagnosed mine, by taking it off my bike and trying it on one that was running fine. I telephoned Triumph Hinckley who sent one out to the dealer for me to pick up. Put it on the bike and bingo works perfect again. Maybe with me being on my 3rd replacement has something to do with it, or the fact that the dealer had no bike to try my old CDI on, as they are all EFI in the UK now.
