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Discussion Starter · #1 ·
Hey there,

I'm just looking for some feedback before I drop a bunch of money on parts. I recently began developing ignition problems as others have in these forums. I was riding my 2002 Bonneville on the highway yesterday and the bike began misfiring and dropping in rpm momentarily before immediately returning to their regular cruising levels. The bike never cut out, stalled, or lost power. I then pulled the bike over to check that everything from a fuel standpoint was okay. While I was pulled over, the idle while in neutral was fine and I turned the bike off and on without issue. I then continued to ride and found that the bike would continue to ride fine then drop in revs before immediately returning giving me a sort of “bucking effect” in terms of riding. I managed to nurse the bike home without losing power whilst being plagued with this issue.
When I parked it, I turned the bike off and when I turned the key back to the run position in order to start it, I had no power at all. I then pulled the battery, tested it (12.48v) and left it on the charger overnight. I came out this morning, connected the battery and I have power once again. I then checked the following systems.

– Checked for spark (both good)
– Checked both plug wires (5.07 ohms, 5.32 ohms)
– Checked primary resistance on aftermarket “Nology” ignition coil (0.7 ohms)
– Checked pickup coil resistance (572 Ohms) while bike was cold.

I’m inclined to think that the pickup coil may be culprit since I’m not stalling out while riding. Plus, power was back today. Am I correct in thinking that if the bike starts and runs, then the ignitor unit must still be functional? If it were faulty, I would think the bike would fail to start at all.

The only thing making me question myself is a comment in another forum saying that the OEM seat and a riders weight may trigger a failure of the OEM ignitor unit. Thinking back, I believe I experienced some of these “misses” while hitting bumps on the road. Anyways, any input or suggestions would be greatly appreciated!

Thanks in advance,

– Zach
 

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I am writing this with the assumption that whatever fault you are suffering is electrical. The same symptoms can occur because of a partially blocked or kinked tank vent tube, or dirty fuel filters etc.

Here is a list of what I can think of, on the electrical side. I'm sure others will chime in to suggest any that I may have missed. I leave out the HT coils since you have already checked those.

  • Faulty pickup coil - these can work flawlessly until they warm up. 2 resistance readings are needed to check, one when cold and the other with the coil immersed in boiling water for a couple of minutes. Both readings should be within about 20% of each other.
  • Air gap - being a 2002 model, the stock air gap of the pickup coil used to be 1mm. Triumph later changed this to 0.8mm, due to the same running problems you are having.
  • Seat pan impacting the igniter connector - the igniter is not the problem here, but rather the connector can develop loose connections over time. With the connector good, people have fixed this by raising the seat slightly (packing the rubbers that sit on the frame rails) or cutting a hole in the seat pan above the igniter connector.
  • Corroded or faulty ignition switch - usually happens mostly with those switch relocation brackets that turn the switch upside down, and water gets shovelled into the switch, causing erosion of the internal contacts. These switches are so bad, don't spend a truck load of money on a new one, go keyless.
  • Poor engine ground connection - the thick cable from the battery -ve goes onto one of the rearmost gearbox bolts, so does the thinner wiring harness ground. Some older models had a small connector on the harness ground which burns out over time. The main ground on the gearbox should be kept clean and tight.
  • Stand switch - if this is making poor connection or the stand is waggling around because of the need for a new spring, this will cut the engine momentarily (if the bike is in gear), until it makes proper contact again.
  • Contact of the HT cables in the ignition coil - speaks for itself. High voltage + poor contact = spark erosion.

That's all I can think of right now. I'm sure there's plenty more.
 
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Everything Ripper said, and then, in my case, it was the ignitor slowly failing, until it stopped working altogether.
 

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Discussion Starter · #4 ·
That's all I can think of right now. I'm sure there's plenty more.
[/QUOTE]

Thanks for the replies! I just took the bike for about an hours ride to try and reproduce the symptoms. However she's running like a champ today it seems.
I checked the pickup coil again immediately after my ride and it came in at 784 ohms, which I believe is within spec. Is it possible that the bike being damp at all would cause these misfire hickups while riding? Reason I ask is that we had multiple days of rain before the last time I took it out and the bike was a bit wet before I started riding.

Thanks again,

- Zach
 

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That's all I can think of right now. I'm sure there's plenty more.
Thanks for the replies! I just took the bike for about an hours ride to try and reproduce the symptoms. However she's running like a champ today it seems.
I checked the pickup coil again immediately after my ride and it came in at 784 ohms, which I believe is within spec. Is it possible that the bike being damp at all would cause these misfire hickups while riding? Reason I ask is that we had multiple days of rain before the last time I took it out and the bike was a bit wet before I started riding.

Thanks again,

- Zach
[/QUOTE]
I wouldn't think so, unless the rain was really heavy and the ignition switch took on moisture. The only way to find out is to keep riding and see if these problems return when the bike is wet.
 

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Just to add something simple to check before digging in to the other guy's great points.
Any chance you are getting some condensation water from the bike sitting all winter. A slug of water does just about what you are describing.
 

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Discussion Starter · #7 ·
Just to add something simple to check before digging in to the other guy's great points.
Any chance you are getting some condensation water from the bike sitting all winter. A slug of water does just about what you are describing.
I suppose it could be. The only thing is that I have been riding for about a month now. Is it likely to still have some condensation in the fuel system that would randomly rear its head now?

- Zach
 

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Probably not. But, if there is water rolling around the bottom of the tank and got over to the petcock and down to the carb bowls ---
Worth a drain of the fuel bowls into a container just to check. Easy stuff first
 

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Hi there

You have all the normal suspects given to you by Ripper. I might add that I had a really odd fault (same symptoms) where the main fuse was vibrating out of the fuse box at a certain rpm, then settling back down to recover when I ticked over looking for the fault... might be worth a two second check...

Hope this helps


Chris
 
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