Number 1 cylinder spark plug out

[Ibiro]

Got a common problem on my CBX and CB750. Both bike have the same problem of #1 spark-plug repeatedly going dead during a ride. Could this possibly be a carb related problem? Help.

[tevan]

Check spark first and go from there.

[Ibiro]

That's my plan. Strange that it's on both machines #1. Perfect again when I change the spark plug. I'm wondering if not fuel related.

[wyly]

That's my plan. Strange that it's on both machines #1. Perfect again when I change the spark plug. I'm wondering if not fuel related.

two bikes, that would seem to me just a weird coincidence.

I'm no electrical expert but if it was spark wouldn't plug #6 be affected as well, they both fire from the same coil. I guess you could switch the spark plug origins on coil #1, if the problem switches to plug #6 then it would be electrical.

my limited knowledge I'd suspect it's an air/fuel problem

[wyly]

#1 spark-plug repeatedly going dead during a ride. Could this possibly be a carb related problem? Help.

what do you mean when you say "dead", is it fouled, melted ?

[Ibiro]

By dead, I mean the plug just quit working. Chased around the ignition system, nothing came up. Component test next.
I'm not sure, but can 1/2 a coil go bad and the other cylinder's side be OK?

[tevan]

Here is a easy check on that one. Switch the coil leads around. If it follows you got it figured out. It is not the coil.

[Michael Vidovic]

Sounds like number one lead might be brittle and is 'separating' a little whenever you fiddle with it. Sometimes connecting and sometimes not. A kink could do that. Has happened to me before. Good luck.