nc30 coils question

[monkeywithaplan]

Just wandering if anyone has much experience with issues with them.
Bike basically crapped itself this morning, running on 2 cylinders and I'm pretty sure that for a while it was sparking on 3 before the final caught while warming up. Anyone any thoughts on if this could be an intermittent coil issue that has finally kicked the bucket before I strip her down later and check the fuel system etc ?

Cheers
David

[Neosophist]

Just wandering if anyone has much experience with issues with them.
Bike basically crapped itself this morning, running on 2 cylinders and I'm pretty sure that for a while it was sparking on 3 before the final caught while warming up. Anyone any thoughts on if this could be an intermittent coil issue that has finally kicked the bucket before I strip her down later and check the fuel system etc ?

Cheers
David

Not likely but not impossible.

The NC30 only has 2 coils.. one fires to two cylinders and the other fires to the other two.

So if a coil dies you usually loose two cylinders.

3 could be a bad plug or bad coil to plug lead but could also be carbs.. did you run out of fuel? (blocked breather / bad vaccum pipe / low fuel etc) can cut of the fuel supply and the bike will drop cylinders and then die as the carbs empty (easiest to check too!) - crack the float bowl drain screws and make sure you have fuel in them.

You can remove the plugs and visually inspect they are sparking.

It sounds more of a carb / fuelling issue but if you have it running you can always swap the coils to isolate them.

[monkeywithaplan]

Cheers. The issue is with the rear two cylinders. New plugs, carbs balanced, clearances the whole heap done.
Got a feeling the float heights are not quite spot on. She used to run on3for a minute on warmup before properly catching and had a wee bit of a strange idle at times. Got a feeling its maybe that exasperated or something. Hopefully

[Neosophist]

Cheers. The issue is with the rear two cylinders. New plugs, carbs balanced, clearances the whole heap done.
Got a feeling the float heights are not quite spot on. She used to run on3for a minute on warmup before properly catching and had a wee bit of a strange idle at times. Got a feeling its maybe that exasperated or something. Hopefully

Swapped the plugs / front to back to isolate them They are prone to easily dying?

If it's at idle that rules out the speedo being removed on a JDM (Japanese bike) as if you remove it then it won't fire on the rears over 5500rpm.

[viper_biker]

Simple things first Dee. Check both ends of the lead for corrosion, make sure the contacts are firm and haven't shook loose. Pull the plugs out of the bike and earth them off the motor whilst attached to the coil, hit the starter button.

No sparky = No worky

[vfrman]

Not to hijack but.... does it matter how the leads from the harness connect to the coils, or are they reversible?

[viper_biker]

I'd say it's more to do with the length of the cables that'd limit you from swapping the left and right side coils.