Hi new to the forums and any help would be very helpful,ive just bought a 97 cbr 600 f3,its only running on 3 three cylinders ,and has backfire problem ,me and a friend have checked everthing,electrics,fuel,etc,the only thing thats left the plug leads look to be on the wrong plugs and i cant see any numbers on the leads,is it 1234 sitting on the bike counting from the left? or is there another way to tell the leads are on the right caps Thanks again

 

According to my manual, the firing order is 1-2-4-3 (left to right) from the spark unit (black box) located under the right side cover.

 

It doesn't really matter on an old bike since plugs 1 and 4 run off one coil, 2 and 3 off the other coil. The pairs fire together. I would look for a fouled plug.....that cylinder won't run as the spark doesn't jump the gap, but the other cylinder on that coil will.

 

Thanks for the reply ,much appreciated,the plugs look ok,except 3 from the left,gap had closed up. What confused me is second lead from the left had #3 stamped on it which didnt make sense .So the longest lead,second from the right goes on the corresponding cylinder ,that is second from the right?.Sorry for being such a dunce but every other bike ive owned the leads were marked especially for thick people like me.I said beforeit was running on three ,it wont start at all now ,just firing on 1or2

 

I finally used my brain,and looked up a wiring diagram,cleaned plugs ,put the caps on the right way round, and the bike fired up pretty good Then the reg/rec started pouring smokeand a nice burnt plastic smell.Ah well .least i got the caps on right!!