Topic: ignition coil failing repeatedly

[veganxr2x]

I've got a 77 CB550 and over the past several months, I've gone through three ignition coils. Its been the left one every time and the right side has never given me problems. When I replace it, the bike will run perfect for a few weeks, then it'll start to only fire intermittently on cyls 2 and 3. The problem is especially bad when I start the bike. I'll have to run it fully choked for the first 5 minutes or so and then cyls 2 and 3 will start firing. After another couple weeks, they'll start failing both when I fire up the bike and also when its been running for a while (scary in traffic). Then a couple more weeks will go by and it'll stop delivering spark completely.

Any idea what's going on?

Thanks.

[Duke McDukiedook]

Have you checked your points and condensers? Bad ground/primary connection?

So you checked them (the bad ones) with an ohmeter to check resistance?

Checked spark wires and caps?

[TwoTired]

By what method have you proven the coil was failed?
What coils are you installing?

Are your spark plugs fouling?  What spark plugs are you using?

When was the last routine 3000 mile tune-up procedure performed?
Carbs sync'd?

Is the bike modified from stock, exhaust, induction, electrical, etc.

[veganxr2x]

I figured it was the coil because when I put a new one in, the bike runs again. Basically, existing coil=no spark; new coil=spark.

I'm using stock coils and newish NGK plugs/wires.

I really don't think the problem has anything to do with the plugs/wires because cyls 2 & 3 either work at the same time or don't work at the same time. I've never had it where one fired and the other didn't. Its an electronic ignition, so no points.

Plugs are fine. Not fouled at all.

The bike is a relatively new build with only about 3K miles since completion and the carbs are brand new Kehein CRs with K&N pods that were professionally installed and synced a couple hundred miles ago. It also has a custom 4 to 1 exhaust that has a small baffle, but no muffler.

[Duke McDukiedook]

To have three separate new coils go bad on you on the same side (if they were decent NOS Honda coils) is kinda high on the probability scale. You might want to invest in some lottery tickets.

[veganxr2x]

Done. I'll check the failed ones with an ohm meter today. Any other suggestions?

[octagon]

i vote for a bad condensor

[Tim2005]

What make of electronic ignition is it? I've got through a couple of Newtronic ones in the last 18 months, both failing on one coil.

[veganxr2x]

Tim- I'm not sure what brand the ignition system is. The bike was built by Lossa Engineering and they use marine ignitions. I've been trying to get in touch with them, but I'm not having any luck. Are your coils failing the same way mine are?

[Tim2005]

The first time it happened I thought the coil had failed, and swapped it out & it went fine- til a few miles later the same problem occurred; turned out it was the ignition unit itself. Presumably while I was swiftly swapping the coil the ignition unit cooled down & started working again!

[Spanner 1]

Not the coils, just coincidence.... it's your 'pick-up' coil/trigger gizmo for cyl. 2+3 or the ignition box IMO..... 3 coils to fail one after another, waay unlikely.

[TwoTired]

Your determination that the coils are faulty is unproven.  You have to test the coils.  At least with an ohmmeter.
Coils rarely fail.
2 in a row is really really rare.
3 in a row, points to problems likely elsewhere.  ...Intermittent wire or controlling device.