Bad coil or fouled plug??

[Knucklehead]

I think this something I've done. Yesterday I dropped a new air filter in and fuel line that comes off the back of the petock came off and I didn't notice it. I started it and soon realized that it was misfiring on the right side. I shut it off and checked the pipes and 3 and 4 were cold. Anyway, I went back in and re-attached the line and #4 cylinder is fine now but #3 is not.

Is it possible for one half of a coil go bad or should I be thinking plug wire or plug? I pulled the #3 plug and it's black and soaked with gas.

I have new plugs so I'm going to gap them and throw them in today. The work I make for myself....

[Black_peter]

I'm guessing plugs..
I mucked around with weak spark for far too long before just replacing the plugs..
Do a search and you will find the thread for checking the
coils..
Once the plugs get fouled they can become toast..
I had cracked insulators too

[Knucklehead]

Thanks BP. The boots and wires look good, I'll try the plugs and I'm hoping that'll do it. Cylinder #2 is firing fine and that's the same coil as #3.

[Knucklehead]

Yep plugs.....about seconds was long enough to kill #3 plug. They were bad anyway and it was a good excuse to swap them out early.

[Special K]

Yeah..........FYI.............those coils seldom go bad, and never 1/2 a coil.

The plugs, on the other hand, seem to foul if you sneeze wrong near them!

And...........since 1 & 4 are on the same soil & 2 & 3 are on the other, any coil problem would show in BOTH cylinders..............


Glad you got it.


NOTE TO ALL: Don't ever use cheap plugs (unless you love changing them out!) Always use the NGK plugs spec'd for your bike

[Knucklehead]

Good advice SK and thanks for the coil info. I used the NGK jr9c and the members' input made them a snap to change.