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I went to take my 04 SM out for a ride a couple weeks ago and had a misfire on the right cyl., opened bowl drains, plenty of gas. Pulled the pods, seems to be drawing plenty of fuel. Hand over back of carb, plenty of vacuum. Compression test, tests fine. Swapped ignition wires from one side to the other same side still misfires so thought I had it and just installed a firestarter, no change. Pulled carbs and disassembled and all seems clear and unchanged. Slide rises when engine is running. Pulled hidden filter just to have a look and it was clean as new. All vents are clear. I do seem to be getting spark on both sides when I pull the plugs and ground them. Squirrel condoms seem fine as do the intake rubbers. (sprayed carb clean when running, no change) Exhaust is also clear. I am considering the pick up coil but would that only effect one side? Left side fires as it should. Right is in and out and worse if I open the throttle, that lead to the carb work but don't see anything.

Prolly electrical. Looks like you've already narrowed the issue to: the misfiring side coil (possible); pick-up coil (less likely); or sparkplug (hey, it can happen, however rare). Good luck!

One other question...does the issue happen right from cold start, or only show up when the engine warms up (say about 8 - 10 min or so)?

No, it's right from cold. I know a coil or crank sensor can be fine cold and fail hot. I already changed the offending plug for another I had. I also swapped coil wires and sparkplug leads to eliminate a bad coil. That's why I came here to see what ideas you guys had. I'm sure I can figure it out but right now I'm stumped.

Well that is a puzzler; looks like you've ruled out almost everything electrical.

Only part left is the pick up coil but I would think that would effect both sides. My only other thought is a broken wire or loose connection somewhere. That would be miserable to find.

I am thinking since I did the firestarter I might do the TTP coils and wires and plugs just to make it all new even though the coil on the bad side worked fine on the good side. I am going to need coils anyway for the hardtail build if I ever get back to it. I have so much ahead of it right now it isn't funny. Breaking my wrist really set me back!

Just put 2 brand new plugs in to be sure that was ruled out and it made no difference.I checked the spark again and it looks good. Unfortunately I don't have an inline spark tester to watch it while running. I got plugs locally because I can get those on my commercial account for $5 for the pair instead of $30 from TTP. I might source HT leads locally too although that isn't the issue either since I took the lead from the side misfiring and put it on the side working and nothing changed.

Grasping at straws now, just pulled the valve cover and checked the valve clearances, all in spec. I also bought the coils and leads but I don't think that is going to fix anything. Next I might order a crank sensor just to complete the set. I also don't think that is the issue since that should cause a problem on both sides.

Hello- that happened to me - it was in the wiring going to that coil. Check the connectors plugging into that coil. Do a continuity check to wires with someone jiggling the wire. Bob

Thank you, I did inspect visually but I will do a continuity test as soon as I can, probably not until Sunday now.

What really gets me is it ran fine when I parked it right before I broke my wrist.

The bike is pissed at you! You can try running it in the dark to see if there is any sparks jumping from wires to ground.

Now it has new coils and wires too. Still no improvement but I have to say I didn't expect any.I have not been able to find any shorts or bad connections so far. I was looking at that carb again because I am at a loss right now as to the cause of the problem. So I started the bike and misted fuel with a spray bottle directly into the carb opening as I opened the throttle. There was no effect so it has to be electrical. New CDI, new coils, new plugs, new wires. Only thing left to replace would be the pick up coil but I really don't see that effecting only the right side. All connections and wires look fine, I unplugged the TPS just to see if there was any effect at all and there was none. It idles on both sides then as soon as I crack the throttle I loose the right side.

I am at the point of taking a sledge hammer to this thing and buying something else or just go back to riding the antiques, at least when they had an issue it was simple and usually fixed in a few minutes to a couple hrs. With this bike it seems everything is in order but the right side misfires as soon as I try and open the throttle. I have fuel, I have spark, I have air, I have perfect compression and all the new parts. I needed those same parts for my project so no wasted money anyway. I can't understand why it doesn't run, I have never been in this position before. I am usually fixing other peoples problems. I have plenty of other bikes and my BMW is even registered but I want to ride the Speedmaster.

Holy crap...at this point, I say try the pick up coil.

I think first I will run a wire directly from the CDI to the offending coil and a hot wire directly from the battery to that coil one at a time and see what happens. That way I can rule in or out a bad connection or broken wire.

I had a problem with the wiring harness connector to the CDI. Pull it out and go over everyone for corrosion. Also make sure each individual spade connector is tight. It's a tedious job but solved my problem.

Ian, I agree with you about the pick up coil affecting both cylinders, not just one. I doubt changing it would improve anything but don't change it until you finish the primary wire check along with the CDI connector check.

It would appear you've been very diligent and checked everything else properly. Swapping coils and still having the original right cyl miss usually confirms a problem with the CDI (replaced), CDI spade connector in the CDI plug, RH primary wires, RH spark plug(replaced) or RH HT wire(swapped). The only thing you haven't done is check those primary wires to the CDI which you are probably doing now or the connector itself (spade connectors for primary wires) as Mike suggested. Don't give up, this is one of those problems that causes you to second guess everything you know.

I think you are on the right track and anything else we say will be us just repeating ourselves. I can't think of anything else you can do. You checked for plugged exhaust, valve clearance, compression, even tried spraying fuel right into the intake eliminating a plugged circuit in the carbs... What else can you do?????

Thank you guys for trying to help, I have bypassed the harness now with jumper wires and still no joy. I have a new pick up coil on the way but I don't think it is going to fix the issue.I am at a loss, I am confident in my mechanical ability but this one really has me stumped. Never hurts to try and get a fresh perspective, sometimes you can be too close to the problem. I played with my old BMW a little bit today too, no issues with that thing, it never fails me.

I didn't check to see if each individual spade was tight but it is well greased and no corrosion at all in any of the plugs and I unplugged every plug in the harness to look. Only connector I need do are the leads concerning the right coil. I used jumper wires but if the spade was loose causing intermittent connection the jumper would do the same. I don't think that is it since if I just crack the throttle and hold it the right side is dead until I close the throttle again. Then it idles on both, if I crack it open hard to nearly full throttle I get sporadic fire on the right and that is what lead me to spray fuel directly into the carb opening thinking I just wasn't getting enough fuel.

Also- I had a carb act up on me causing one cylinder to cut out - listen to this - left over spalling (metal shavings) that are supposed to be removed after they make the carb - had gotten unstuck from one of the passage ends causing carb to cut out. Took a syringe full of alcohol kept squinting though passages with jets out etc. - wouldn’t believe metal shavings that came out. Been running my spare carbs ever since. Anything can happen with these things.

I shot fuel directly into the back of the carb and it made no difference so I don't think it's fuel delivery. I can also see fuel being drawn out5 of the main jet while running.

Also - I found so many faults in my wiring harness I ended up rebuilding the whole harness- removing all the lawyer stuff getting rid of the diode etc etc and solding all the connections adding thicker better wiring rewraping with harness tape etc. if I remember right found lots of problems at the connections at the cdi and right coil wasn’t grounding well. The worst harness connections I have ever seen. I really had a lemon for sure.

Should have seen the way the antiques were done, they pushed wire through the bullet connector and folded it over and plugged it together. No crimping, no soldering, nothing.

Very interested in how you get on with that replacement ignition sensor, a/k/a pick-up coil.

I'm interested too. I seem to remember early on, Triumph had a bulletin stating that the pickup coil clearance was originally too great at 1mm and was to be reduced to .8 (correct me if those values are wrong). I think Triumph stated this could cause a misfire?? Do you remember that one Ian?

YES Gregger, this was in the "Vault"...

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Pick-up coil Air Gap change
wojo #48250 01/01/2008 11:34 PM
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wojo
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Amherstburg, Ontario, Canada

The gap for the Hall Effect pick-up coil, located behind the right engine cover, was changed during production due to warranty issues, the following was sent out as a statement;

Affected Models: Bonneville/T100, America, Speedmaster, Thruxton and Scrambler.

Should a bike (see above) demonstrate faulty ignition coil type symptoms (most commonly an engine misfire), please initially check and adjust the ignition pick-up (IPU) air gap (we recommend an air gap of 0.8mm).

Since changing the IPU air gap in production to 0.8mm, we have had no ignition coil warranty claims.

Triumph manual, chapter 16, page 47 has the alignment procedure...

Thanks to members Sightglass for originally posting this and TonyG pointing out that it should be in the tech vault.

Last edited by moe; 03/04/2010 9:49 PM.

I wrote that down back when we first discussed it. I have it in the notes in the back of my factory manual. I did that adjustment on our bikes back then.

Taking forever for the pick up coil to get here. I order from TTP on the other side of the ocean and get it in 3 or 4 days but order from a little over an hour from me and it has been a week and still not here.

Usually Slow Postal Service. In days gone by, I would just drive over to buy parts directly, check out the bikes, & then stop in Cabelas on the way back.

Same here but I have too much other stuff going on too. My friend/boss gave me another truck, 86 Dodge 250 That has an issue. He was told it needs an engine but it runs fine but over heats. I just looked at it today and both rubber gaskets are gone on the radiator cap. But he also gave me another 360 I had to pull myself, so I did it today so he could scrap the truck. Too bad, that cab and frame are clean too like mine and it was a 350 with a dump body. I am part way through a tranny and gas tank job on my 96 GMC 2500 4X4. That needs fenders (I have) and I want to remove the bed and clean up the frame before I put the new gas tank and tranny back in. I also replaced the fuel lines, all the brake lines with nickle copper, and sending unit/fuel pump. That cab and bed also have no rust on them. I am half way through restoring another 8N tractor that is in my shop, all mechanical stuff done and 1/2 way cleaned up and painted. The there is my hardtail project and pouring a slab for a new 10,000 pound Worth lift I have, house needs a roof, etc... Dodge should be a quick fix since all I have to do is fix the over heat issue, it runs fine and body is clean except one small spot over the left rear wheel. If all goes according to plan should have the GMC, Dodge , and 8N done this summer, have to see what happens. I ended up working this afternoon, they got a truck wreck (tractor trailer, motor home, and a car) and only had 2 guys on so I did a winch out then had a state police wreck I also did.

I actually always stopped at Cabella's on the way home too.

Pick up coil installed, no change. I am stumped. Entire ignition replaced, can't find any shorts or bad connections, carb is fine as far as I can tell, getting gas to it, all passages clean, slide rises like the left. Shoot fuel directly into the back of it and no change. Compression is 150 psi on both sides. I am ready to put it in the back of the shop and get something else.

Wow. This is the first I have heard about something like this. Just a wild guess; I wonder if the wiring connecting the CDI could be bad.

Visually, no and I tried manipulating wires at all connections while running. It should run but it doesn't. I even bypassed the harness with jumper wires.

If I lived closer to you I would take that headache off your hands.

Not getting rid of it, I have every motorcycle I ever owned except 3, the minibike I had when I was 7 a dirt bike I had at about 10 and a 75 GT550 I traded for my Norton. I will eventually figure it out, just very frustrated, I never had an issue I couldn't diagnose in less than a day. That and when I swapped coils and the misfire didn't move I thought I had it.

Hello- if you have the colorized electrical schematic in the back of the Haynes manual that will help you figure out problem -when my America was doing same thing helped me traced down problems.With out that intensive schematic would have been impossible at least for me.

I bought an inline spark tester and I am not losing spark. Must be something in the carb I am missing I guess. Got my old BMW R50 out that I haven't had running in a few years even though it has been insured and registered. Got that running and went for a short ride. Not running quite right, carbs are pretty bad and I ordered new sparkplug wires. I also ordered new Chinese carbs because that is the only direct replacements I could find. The old ones are just beyond repair, they work but not right.

If you need carbs I have a spare set or two...the throttle plates may be removed...will need to look & see what I have.

If you have a spare set let me know, I don't know what else to try. Thing is I can see it drawing fuel, slide rising etc.. I could at least swap them out and see if there is any change. I couldn't believe what new carbs cost for my bike. I would be happy to send them back to you after I try, or I could send you what ever 2 I don't use. I can buy a generic CVK for $75 but the ones for our bikes is $700 to $1400 depending on the engine number. I have other carbs here but not that belong on our bikes, they all have cable operated slides and would take modification to mate to the engine.

I can prolly hook you up, just need to get to the garage attic and see what I have. Need to move some vehicles & do it when it isn't 115+ degrees up there. More to follow by private message when I see what's what.

Thank you, you are a life saver! As far as I can tell my current carb is in working order, when I spray carb clean in the different passages it seems to come out where it should but I don't have any other ideas left. I don't want to spend a bunch of money testing my theory. I already spent a bunch thinking it was electrical, the CDI because testing pointed to it and coils plugs and wires to rule them out and the pick up coil just because the rest was new. A note on the pick up coil, they only list one for our bikes and the boot points the wrong way where it comes out of the stater cover, down instead of up. I didn't want to spend a ton on carbs to find out that isn't the problem, if it isn't it must be in the engine but I really don't see that being the case.

Just read through the thread and been through a similar problem with my Grandsons Honda VTX 1300 v-twin. it is a 2004 with 4,000 miles and is a beauty and had been sat for years. Cleaned the carb and new plugs and ran good for a few miles then sooted up the plugs and front cylinder cut out. ALWAYS front cyl. going bad changed front coil, checked plug wires resistance. replaced wiring from Ign.Control Module to front and rear coils fired it up and ran on both cylinders, put side panels on bike and seat and got ready to take it out and it wouldn't fire up. Just couldn't believe it. We checked the blade type fuses and found the ignition fuse blown, replaced it and all worked well and is still running strong. The fuse had "blown" but not how a blade fuse normally does. All blade fuses i have seen blown seem to shear across the top of the "U" or upside down "U" actually. This fuse looked like it had started to blow out on one side of the "U"but it still managed to somehow allow enough current to power the coils and as we kept trying to run the bike it allowed the leg to bend but as it did the leg got thinner. The thinner it got the more it got hot and "stretched " apart till it finally broke for good and not even one coil would fire. Then we finally found the culprit. A BAD FUSE, slowly blowing under load. It led me a right old song and dance as we say in England. Maybe just maybe you might be having the same issue. Checking all the connections in the fuse box may help.

It's something to look at, I did check the fuses but didn't actually pull them out.

Hey Ian, good news, I have a complete, unmolested set of carbs I am willing to sell. Your PM box is full, so PM me when you are ready.

Sorry about that, I deleted some.

PM inbound, replied to yours. I could not send a new PM thread, apparently you are over some limit...

I deleted several pages and was still deleting stuff from 07, I had no idea I had so much in there. I want to keep a few of them so I have to be selective but will eventually get rid of most.

How'd you go Ian....you end up having a win
Seems very strange to hear you asking for help 🤔

I haven't been able to get back to it. Was a time I would have thrashed day and night until it was going again. I have been working on my truck and I refurbished and old Rockwell jointer that I started when I was waiting for parts for the bike. I have a set of carbs to go through and try now but haven't had the time to do it. I have had my 64 BMW out a couple times but I really want my SM going again.

Got the 2nd set of carbs gone through and put them on yesterday, No change. Really has me stumped, has to be something that effects only the right side, I really thought I missed something in the original carbs and the 2nd set would clear it up. 150 PSI compression, valves in spec., new CDI, new coils, new crank sensor, new wires and plugs, changed cabs, bypassed harness for power (as test, put back when didn't change),crank sensor (pick up coil) set to new spec ( was already set to that with old sensor too) Can't be intermittent sticking valve as it doesn't vary always acts the same. I might have to take it to Hermy's and see if they can figure it out, I can't believe I am even considering letting anyone else work on one of my bikes. I have never done that before.

FWIW, I doubted it was the carbs. That said, given everything you have done, other than a faulty connector or wire, I don't know...

I know, I didn't think so either but I was at a loss. I had gone through my carbs twice and sprayed gas in the back of the faulty side with no effect and could see it drawing fuel I was just hoping and grabbing at straws. I bypassed the harness so I doubted a faulty wire or connection. I also replaced the entire ignition system so to me it only really left an issue with the right carb. I also used an inline spark tester and I don't lose spark. I will have to get out my power probe and trace the harness to see if I have a broken wire or faulty connection I can detect with the transmitter attachment. This all started when I had to let it sit a season because of my wrist. I have extra carbs besides the pair I bought but not direct replacements.

Man I hate when you have to keep chasing a problem . Sounds like you have done everything I would do so ill throw something out there just for the heck of it. The pick up coil is triggered by two spots on the rotor,stator or whatever they call it. One for the left cylinder and one for the right so maybe the trigger point for the right cylinder is not as efficient or is somehow hindered from translating that magnetic pulse to the igniter.
I am really reaching here and have never run across anything like that before but when everything else is doing what it is supposed to do, that is really the only variable left.

Thank you for the reply Chy, the rotor has very strong Magnetism and I didn't see any physical damage. I thought about a sheared key but that would make the left side not fire right too.I really haven't worked on it lately, too many other things that have to get done and I do have other bikes I can ride. If this was one of my antiques it would have been fixed long ago. Very frustrating.

Ian, have you had any luck recently chasing this issue or have you put it to rest for the Winter? This is one that I'm really interested in since it looks like you have tried every trick we have learned about these bikes to resolve this problem.

I have been doing other things that I have to do. My shop has an 8N tractor project in it that I reseated the valves and new carb to get it running. I got it with a blown head gasket. The main tractor is about 1/2 painted, everything works on it now. I also have my hardtail project on the lift in there. Mt 2500 Chevy is blocking the door with no transmission in it or gas tank. I took that apart then broke my wrist. Then this summer I spent catching up on things I had to get done that I couldn't do while my wrist was healing. My boss/friend gave my an 86 Dodge 250 Royal pick up and I spent some time on that so I could drive it. Junked to us for a blown engine and he gave me another 360 that I pulled out of a dump truck. Then when I went to swap engines I took the radiator cap off to start draining the coolant and noticed the rubber gaskets were gone so I replaced that and started driving it. It had a minor ignition issue that I fixed too. It ran OK but wanted to stall at idle. I bought an HEI distributor for it but found out it fit but I couldn't turn it to set the timing without cutting away part of the intake manifold. Turned out the gaps were wrong on the pick ups so I set them and been driving it ever since. I only got the HEI because Dodge in those days use the antiquated ballast resistor set up and the ignition modules were not very good. I may have HEI in my future. The truck in pretty clean inside and out no rust except above one rear wheel and has cap and bed liner. I want to clean the frame of the chevy before I put the tranny and gas tank back in. That truck isn't rotted either, it's a 96. Sorry for the long reply but just got logged back in after the computer crash.

I am late to the party on this, but reading through what all has been done and checked, not much left but a couple things.

reading your story, it all pointed to the ignition pickup, I was surprised that changing that did not resolve the problem. However, I have been down that road before and found that my replacement (new) pickup sensor did not work either, it can be checked with the multimeter, values in the manual. I finally threw an old pickup sensor off a running bike on there and it fired right up.

otherwise, the main grounding at the back of the engine case should be checked. Take it off, clean and sand and reassemble. It is it a great location for unseen corrosion.

this is a long shot, you said that compression is good, for how long? does it hold for a long time? or bleed over a few minutes?

Holds quite a while.I have not checked that ground.