Cylinder not firing - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 3 (permalink) Old 05-30-2012, 12:25 PM Thread Starter
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Cylinder not firing

Well, since it's been nice out I've just been riding my bike instead of selling it and fixing a few things that I never got around to before.

The PO never changed the air filters so they were in a sorry state. I recently changed them (OEM and they came pre-oiled) and now I am losing my front cylinder on idle. Since I've been traveling, I drained the bowls and filled them with seafoam for a week. Got back yesterday and it is still doing it. Here is all I know/done:

Bike starts right up and climbs in idle like normal for 30 seconds or so. If I don't touch it, and it stays at 3000 rpms, all of a sudden it drops to 1100 and the front cylinder (which was firing) now stops firing and I can smell gas. Bike has new NKG plugs and the carb screws are 2.5 turns out. Battery seems fine.

The front spark plug wire test is a little confusing to me so I haven't been getting any results on that.

Any thoughts? Grounds are tight. Did a test at night and it didn't arc. I am leaning towards a carb issue, but why would the idle jet work for a tiny bit then stop without any application of throttle?
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post #2 of 3 (permalink) Old 06-01-2012, 10:49 PM
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Any chance you pulled the front ignition coil at any point? Wondering if you have a loose ground wire that's losing contact at higher rpms.

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post #3 of 3 (permalink) Old 06-01-2012, 11:55 PM
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Hey Papa,
Are you running iridiums? Have you done the pick-up coil gap?

Since you changed the filters, they may be offering a more rich mixture. Once the motor warms, the ignition might be getting quenched. I think I would back off the mixture to two turns and see if anything changes.

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