Stick Coil Diagnoses

[ebincia]

Hello all,
I just went through the Stick Coil diagnoses this afternoon after suffering hesitation problems for a year or so. New plugs helped, but it was a short time fix.
Today I pulled the lower plug caps (one at a time) and grounded appropriately. Both sides showed a significant change in running. Then I pulled the stick coils (one at a time) and found that there was no spark at all on the left side. I switched the coils left to right and the spark followed the good coil (now on the left).

Here is my plan. Correct me if I'm wrong on this :
If there is no spark then that stick coil is toast (Replace)
It would be wise to replace both coils as a set as the other side is weak as evidenced by change in running when removing the lower spark on the opposite side.

Thanks in advance for your response(s).

[Dr. Strangelove]

I think your reasoning is correct. There is a thread about stick coils and running mildly poorly that I was involved in about 18 months ago, I think.

viewtopic.php?f=2&t=19350&hilit=stick+coils

I replaced both because on my shelf I see a used but functional stick coil. Maybe others will chime in?

John

[towerworker]

When mine failed (about 2 yrs ago) the bike ran poorly but only on hard acceleration. The positive diagnosis was when pulling one secondary (while at idle) and engine stalled. To confirm I moved stick coil to other side and failure followed. I replaced both, figured at some point the other would follow.

[ebincia]

Replaced both stick coils...OMG!!!!!! what an incredible difference in performance, idle, start up, gas mileage and this all comes with a lot less vibration. The $250 bucks was worth it to get my engine back.

Thanks all.

[iowabeakster]

Well done... Good diagnosis and fix...

How many miles does your bike have?

And for anybody else with stick coil failure, how many miles when you replaced them?

My reason for asking is that, sometimes, my bike is feeling excessively vibey lately. Sometimes at RPM's when it is usually smooth (3500).

and this all comes with a lot less vibration.

I've been through the whole vibration troubleshooting routine. Valves (and rechecked), TB's (numerous times), new plugs, coil test (as above)... I even ran some seafoam this week (I usually try to steer clear of additives). I don't have much trouble getting it started, and the mileage has remained consistent (45 mpg).

-edit: Sometimes the idle gets a little rough when it is hot.

The thing is that when I tested the coils a month ago, my bike was completely cold. It started fine with only the primaries, both sides. But, I got it started and only let it run for 5-10 seconds, both sides. I wonder if my coil(s) are getting less reliable, but only when hot. I really want to avoid a 250 dollar experiment, but I'm running out of ideas.

[ebincia]

Well done.

How many miles does your bike have?

37,000 miles on it. The oils started going bad at about 30,000. I replaced the spark plugs and that seemed to fix it for a while, but deep down I just knew something else was wrong.

[Dr. Strangelove]

Some info...

I replaced mine at 59k miles, though only one was bad. It seemed to perform well enough, but my mileage went down almost 10% with the bad stick.

Now, I am at 81k miles. I just did 2000 miles to and around Arkansas (best motorcycle roads in the US imho)
Stella! seemed to have all the power I wanted, but she was a little buzzy around 5k, enough to notice it through the seat. Also, again my mileage seemed to be down a little, maybe 5% from customary.

Because of my past expereince w stick coils and the sometimes VERY subtle nature of a bad one, I tested them this evening, by pulling the secondary plug.
At fast idle, pulling the LH one-> no difference
pulling the RH one, the idle dropped about 100-200 rpm, still smooth, but slower. It seemed to rev fine.

I still had a good stick coil from when I changed both of them at 59k. Put it on and no drop in idle when I pulled the secondary.

So, now I have had two stick coil failures, one at 59k, one after 32k.

but deep down I just knew something else was wrong

yes, exactly, you just have a sense about it, something is not optimal

John

[gregor]

Remind me what that secondary coil is supposed to offer?
Glad I've a single plug model. Just changed my plugs and air filter the other day and the vibes have abated somewhat.
Cold gales and rain may be bringing my summer riding season to a close.

[Karter]

i had mine replaced and i still had no spark on the right side. It turned out that my MCU (Motronic Control Unit) was fried. I found a new one on Beemrboneyard and plugged it in, working fine now. This was the second time and the second MCU to go down on my 2004 R1150RA. The dealer mechanic seemed to think it was shorted out due to inproper wiring of the spark plug, which was swapped when the first MCU blew. They said it had been bent.