I own an FZR 400 genesis (1986) with approximately 60,000km on the clock. About a month ago I noticed the odd backfire sound perhaps once everytime I took it out, and over time it got more and more frequent.
Suddenly last week the engine started sounding terrible somewhat like a lawnmower or old single/twin cylinder bike. I stopped riding it but have failed to find the problem. Only the exhausts for cylinders 2 & 3 were getting hot.
I have checked the resistance of the primary and secondary coils in BOTH coilpacks, they were found to be the same and within manufacturers specs. I had checked sparkplugs and they looked fine. I took out the first and the four spark plug leads and connected them to plugs and could see no sparks when turning over the engine with the starter motor.
Finally I bought a 2nd hand CDI with the same serial etc fitted it and the situation was no different, finally i swapped over the 'low tension' connectors to each coilpack and the bike would not start at all

Could it possibly be one of the 2 relays wired in with the CDI?? or is it more likely to be the coilpacks? (i have another one for cylinders 1 &4 due in the post.
Many thanks in advance!
