Bonneville America Forums Forums Technical Forums General Tech No spark on left cylinder

So this started on Saturday. Wait, actually it did this last year after winter, but I'll get into that later.

So here's the problem. Got the bike out to "warm it up" Saturday and it would only run on the right cylinder. I could tell the left side is getting fuel, could smell it. Let it run for a minute on the right cylinder, then all of a sudden the left side starting running. Ran on both cylinders for about a minute, then back to only the right side. Great, an intermittent problem

So now the troubleshooting starts.

Went and bought new spark plugs, no difference.

Switched the spark plug wires, no difference - so they're good.

Then took the coil leads from the right side coil, connected them to the left coil, ran a spark plug wire from that coil to the right cylinder. The right cylinder ran, so that tells me both coils are good.

Took all coil connections and the CDI (ignition, ecu, box under tank, whatever you would like to call it) plug off and cleaned them. No change.

Checked the battery connections, all good. Then while my troubleshooting, the battery went dead.

Then I remembered the battery went dead last year and I had to jump it at one point. Didn't have any other problems with the battery until now. Could a low battery (or bad battery) cause this? Even though the battery starts the bike, is it possible that it is not giving the ignition system enough power?

Oh yeah, throughout this I was checking for spark to confirm that is actually the problem, no spark on the left side.

Also, to get back to the beginning of the story, this happened last year when I first got the bike out but quickly "fixed itself". I am thinking it is the ICU, but before I go and put out $250 for a ProCom, I would like to see if anyone has any ideas.

No, sadly, I have no better ideas. My ignition module died during a rear tire swap never to work properly again...my left cylinder was dead, too. I'd guess the black box is a goner and a new Procom or a used item from Pinwall Cycle will fix you right up.

If possible, find a known good igniter / CDI and swap it out to test yours. If yours is bad, ask a dealer to put it through to Triumph as a "*goodwill claim." You often don't get this facet of extended & semi secret Triumph warranty unless you ask for it specifically.

Triumph replaced mine in the manner described above well after the original warranty had expired, saving me over $500. I had two dealers withhold the "goodwill claim" and found out about it by asking a 3rd dealer. The 3rd dealer did it via phone at 100 plus miles away, and didn't need the old igniter or proof of failure.

Can't hurt to ask...

*While pursuing my warped front rotors issue, a 4th dealer 150 miles from the 3rd dealer also used the phrase "goodwill claim" when referring to Triumph honoring out of warranty problems.

If memory serves, Terry/Snert from SW PA has had 5 or 6 igniters replaced for free long out of warranty. (I think he's spilling Oonse on them) I have a feeling the dealers gets paid for a little bit of labor to change the CDI via a goodwill claim, making it worth their time to try. I could be wrong. I figure since it was free, I can change it myself quick enough anyway. I was just glad to have it for free.

Sure does sound like the CDI unit. Some fellows had the single cylinder symptom caused by a weak pickup coil either do to it being out of adjustment (.8mm) or shorted out. The best way to eliminate it as the problem is to get your hands on another CDI unit like Bucky stated.....maybe one of the gang here could ship you their spare for test? Anyone?

Ebay had them for $229 to $239. Here's one up for bids.

Just saying that I had a loose spade connector on one of the coils which caused a cylinder to cut out.

Gregger and Keith bring up two fine points and one of those might save you some serious bucks. Look at those spades very closely then get a right side cover gasket and check that pickup coil gap first to make certain it's set to .8mm (the book's figure is wrong). You might just get lucky <:-)

So I tried everything that you guys mentioned to no avail. Much thanks to everyone anyway for the advise! Now I guess my next questions:
1. Has anyone noticed a difference in quality between the ProCom unit and the factory ICU? I realize that most of the time OEM is much more expensive, but it almost seems too good to be true for the ProCom to be so much less. Let me know your thoughts.
2. If the answer to #1 is no real difference, then I'll probably get a ProCom off Ebay. In the pics the unit does not come with the bracket. How do I remove my existing bracket off the stock unit? It looks like it is being held on by rivets. Do I need to drill them out?

I ran across this CDI recently... not sure who makes it though. I've been under the impression that ProCom is the only one that makes after market CDIs for our bikes... maybe that's what this one is.

http://www.electrosport.com/street-bikes...0-t1292370.html

Keith and all,

Electrosport and Procom are the same company.

Bluto

After sitting all winter in heated garage on side stand,fuel run dry.both SM's seem to run on only one cylinder for a short time.?

Well, got the new ProCom on Thursday, installed it and everything seem great Went out for a short ride yesterday after work to Capitol Area Triumph and no problems whatsoever. I'm very glad that did the trick, so is the wife (if you know what I mean). We both would not have been too happy spending $200+ and not fix the problem.

Thanks to everyone with the great support and answers to my questions

Now, I think I'll start another thread (after searching first) to figure out if I should load another program from their website.

Glad it worked out for you. Let us know if the Procom unit improved performance and what setting you are using. Much appreciated.

.....which map did you install in your procom cdi?.....I was very disappointed with the default setting, but love map #5

I'm actually still running the default, was thinking of map #6, but really don't understand the differences between "intermediate rider" and "experienced rider". Looking for advise. The only modifications I have are pipes (not sure what kind) and a K&N filter.