Number 1 cylinder spark plug out


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Ibiro
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Number 1 cylinder spark plug out

Post by 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
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Re: Number 1 cylinder spark plug out

Post by tevan »

Check spark first and go from there.

Ibiro
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Re: Number 1 cylinder spark plug out

Post by 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.

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wyly
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Re: Number 1 cylinder spark plug out

Post by wyly »

Ibiro wrote: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
CBX a work in progress, still improving...GS1150EFE completed and awaiting modifications.....RD350, remnants in boxes scattered throughout the garage

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wyly
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Re: Number 1 cylinder spark plug out

Post by wyly »

Ibiro wrote: #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 ?
CBX a work in progress, still improving...GS1150EFE completed and awaiting modifications.....RD350, remnants in boxes scattered throughout the garage

Ibiro
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Re: Number 1 cylinder spark plug out

Post by 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
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Re: Number 1 cylinder spark plug out

Post by 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
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Re: Number 1 cylinder spark plug out

Post by 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.
...always walk out of the room smarter than you walked in...

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