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Discussion Starter #1
yes, i know sooty black plugs are a sign of running rich. But the bike hasn't been rejetted for many months and has run great and still does. But the plugs are totally black with soot. The uni filter is clean and i can find nothing blocking the intake to the carb mouths. I would think if it were fuel something would have to be blocking air flow BEFORE the carbs since it's showing on both plugs. However, dowop at BA told me when he recently had stuttering problems at a certain RPM and sooty black plugs, replacing the coils cured it. My problem tho is a cyclic vibration at 15-25 MPH in 2nd gear. But i'm beginning to think it's related to whatever is causing the plugs to be sooty. And since it's unlikely to be a fuel/carb problem since both sides are like this, dowop's reply to me at BA makes me wonder. Can coils cause my pronblem with the vibes, and can they both go bad at the same time or would that only happen by coincidence? I will check resistances tomorrow, but from what i know thats not a sure test since they may change under load. Any thoughts?
 

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Yep, weak spark can cause incomplete combustion, which looks like rich running........and stuttering, although it usually shows up when the coil is being stressed, which would be at start up and at high rpm. This may sound weird, but look for a loose connection in the wiring, or a chafed spot. Perhaps the ignition or the kill switch.
But, I believe the coil is a dual fire item, hence both sides would be affected if it were defective. So, if you have a spare for a test, go for it. Also look for loose connections. It may have to do with a certain rpm yielding a resonance and causing the problem.
 

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Discussion Starter #3
Thanks. I was indeed considering a dirty contact in the ignition or even is the supply voltage wiring or even as you said the kill switch. As for swapping coils tho, they're $300 a set so thats not gonna happen. If i did need coils tho it would be a perfect excuse to get a set of nologys. :-D
 

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Well, it was the coils. secondary is completly open on both coils. They're under warranty but having no way to get back from the dealer then back again i'm screwed. They won't allow me to just bring the coils in or do the work while i wait. Guess it's nology time.
 

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i think i got lucky here. I found a dealer who will check the bike on the spot and hand me a new set of coils on the spot once they have some in. (due in wednesday) I just hope i don't find that the guy i talked to was wrong and get down there to find a different guy telling me what all the other dealers do.......that i have to leave the bike there for a week or 2. In that case it WILL be nology time. But if this guy is straight up about this i'll get new coils under warranty. I just hope it cures the vibration. On a rather amzing note, a guy at BA just posted in reply to me saying he's been following my thread because he has the same problem...footpeg vibes at 12-25 MPH in 2nd gear only ! He also just got new tires when this happened, and that speaks to the liklihood it's a tire thing and that the coils going out at the same time was coincidence. But he's gonna check his plugs to see if they're sooty. If they are and this turns out to be the reason for the vibes, imagine what a huge coincidence that would be ! We both have out coils go out right after a tire change and with identical symptoms ! That would be one for the books w/o a doubt. Anyways, i hope this is it because my bike has been out of comission for a month and i'm getting very cranky.
 

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Dazco - I don't understand why, if the problem is coil related, it happens only in 2nd gear? Why not in first, third, etc, at the same rpm range? If it was my bike, I'd be puzzled, too.

I would have to agree with Mechanica, that perhaps a certain resonance unique to 2nd gear/specific rpm, is causing a loose connection, if the vibes are ignition-related.

I would rather rebuild an engine than troubleshoot an electrical/electronic problem. Not my forte!

Good luck in getting her back on the road.

Bob
 

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Discussion Starter #7
I would have to agree with Mechanica, that perhaps a certain resonance unique to 2nd gear/specific rpm, is causing a loose connection, if the vibes are ignition-related.
I agree partially. If the bad coils ARE to blame, it's definatly an issue where a certain resonance is setup just at that small RPM range/gear due to the weak spark. But it's not a loose connection but a open secondary. These coils are one of those problematic Triumph issues that a lot of people had. So it didn't need some other condition to cause them to go bad. So the resonace isn't what caused the problem, it's a symptom of the problem. That is, if indeed the coils are to blame for the vibes. (fingers crossed big time)
 

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Put in a new set of plugs and see if the problem clears up. If it does you really are too rich, which i think you are for the mods you have done. 120 main should be enough for your mods but you would need a dyno run to verify. good luck-T1
 

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Discussion Starter #10
It's not the jetting. I've been running the same setup for close to a year and the plugs always looked good. And 120's come as the stock mains, so i can't imagine why 120's would be enough after opening up the exaust and intake a lot, especially considering they are considered lean in the stock configuration. Pretty much everyone who mruns a setup like mine runs at least 130's. And the fact it's run great with perfect looking plugs for a year makes no sense that it would all of a sudden be too rich a year later w/o touching the jetting.

But again i have to do a 180........as benny told me at BA, the secondary SHOULD be open. Thats what i thought to begin with knowing how audio trannys work. But i wasn't sure if it was the same with the coils in an engine. I wanted to believe there was a difference because it would mean a possible cure for the vibration. But he confirmed the secondary should be completly open in reference to the primary. So the coils are apparently good and the search goes on. I hated the idea my coils were shot, but on the other hand it would have been a possible fix and therefore gave me hope. So i guess i'm back to square one. But i think if i get this sorted i may get nology coils anyways.
Anyway, the look of the plugs are another problem besides the coils. Maybe related or maybe not. Whats really horrible is that i now have 2 things to troubleshoot. Things went so smooth till now a year+ later. I guess it's inevitable unless you own a honda. But i do appriciate my bike's uniquness.

[ This message was edited by: dazco on 2006-09-30 22:50 ]
 

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Daz--it would seem to me that if you've now got another BA rider with the same issues right after a tire change, you're getting a big pointer in the direction of a tire problem. I would get as much info as possible from this other BA rider and then think about going back to the shop that installed the tires.
 

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Discussion Starter #12
Naa......the tires are out of the equasion as far as the vibration. Today i found that if i rev it very slowling in neutural, it has a srtong vibreation right as it hits 2.2k RPM's then stops as it passes that point. So i have an engine tranny or ignition problem. Not a good day. I can only hope it's the ignition, but i don't know where to look.
 

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Well, if you really want to get serious, strobe the timing. You'll have to pull the timing cover and hook up a strobe timing light. Take it up slowly and note the timing. If you have an anomaly at that 2.2k rpm, you are onto something. If not.......well..........
Keep a fan or some breeze on the bike if you run it for long while stationary. Do it with the bike hot, and have some chill spray available to cool the pickup and see if it continues to malfunction. Then chill the ignitor.
 
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