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Discussion Starter #1
well I don't post here often, tend to lurk since im a bit of a new to triumphs and hate asking stupid questions and wasting people's time but i've hit a wall and im finally breaking down and posting,


So here's the deal

got a 72 triumph T100
Running points / alternator with tympanium / 12v dual lead HD coil - single condenser positive ground , have tried with a cap. and now have a battery wired up 12V battery with around 120 CC amps ,

So basically theres no spark , this is a brand new wiring harness
and after the initial wiring job I did have spark, however i was unable to get any real combustion so pulled the carbs found a mess cleaned those reinstalled and in the process of doing so i managed to pull one of the 2 leads coming form my alternator loose in that process i blame beer .. well at this point i had a lead set up on my switch that was to go to a rear brake light not yet wired due to a limited color supply it happened to be the same color as the leads to the tympanium stupid i know .. should have not wired it there at all should have striped it with a sharpie something, well that left one lead going from the alternator straight to the switch on the same terminal as the coil ( neg side ) going down inevitably to the cap also neg side of the coil , prob kicked it 6to 7 times total like this .. before realizing i shouldn't drink and wire at the same time ..

corrected this .. no spark ..
put in new points , gaps on the points are about .020 as per using the HD coil set up , gap on the plugs is per the manual using NGK plugs using the proper plug ( i forget the # right now )

at this point i wired in a battery, eliminating the entire charging system .... heres where im completely baffled ( sorry for the back story )

wired in batt. - no spark
when i turn my switch over with the plug grounded to the head i get a single spark out of it .. I can repeat this and continue to get a single spark , so i took the switch out of the loop and tried just toggling the batter on and off with the coil and get a single spark -
It only sparks once when the switch is engaged or power is toggled on, and when left engaged it will not produce a spark on kick

grounds are solid no paint on the frame - points don't seem to be grounding out verified all the spacers are in place for the points wires condenser is grounded -

about to swap the condenser just in case the wiring mishap damaged it , but otherwise ( and im not too hopeful thats going to work ) I'm stumped

any thoughts idea's suggestions

thanks in advance everyone and sorry again for the novel,
If ive missed an obvious search topic then i apologize in advance


Brandon
 

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On the points, there is a little plastic sleeve and washer arrangement that insulates the breaker arm. It sounds like you have faulty insulation ( probably none) there. To test. check for continuity from each coil connection to ground. That shows the points are connected to ground. Just manually lift the arm to break the points gap. ( put piece of paper between points) The connection at the coil should now not go to ground. Be wary that you do not damage the coils with this fault existing, as continuous on, without firing tends to overheat the coils.
 

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If the coil is sparking on-demand, then it would seem to be good. It would seem that the plugs and wires are also good if you used them as part of this test.

The condensers are just capacitors, and easy to test. Discharge a condenser by shorting the post to the case, then measure resistance with an ohmmeter. It should start off as a dead short (0 ohms) and climb to an open circuit as it charges (infinite ohms). You should at that point be able to measure voltage across the condenser's terminals with a voltmeter set in the "ones" range (as opposed to, say, tenths or smaller or tens or larger). If it doesn't behave like this, the condenser is bad.

Question: The switch you refer to, is it your engine cut-off switch, or a test switch that you wired-in to bypass the points to test your system? If it's your engine cut-off, your points probably need some attention. The wires coming off them need to be shorted to ground when closed, and open when open. I'm with Panda here, it sounds like your points are shorted dead and never open, or there's a wiring fault-- as a result, the voltage going to the coil sounds like it's only being interrupted when you disconnect the battery side. That's functionally similar to how points that are working correctly would interrupt the circuit.

--Scott
 

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Discussion Starter #4
the switch i was referring to was first a key switch and then when i removed that from the loop and wired a toggle switch between my battery and my coil leads to basically do the same thing as my key switch, no kill switch on the bike at this time , but i suppose wiring it with the toggle switch to run direct power to the coil would be in effect a kind of kill switch .. when i think about it, hadn't thought about it like that, but yes the points were still in the loop for that test.

Thanks guys ill take a better look at those points i had checked the wires on the points to ensure the plastic housings that protect the leads from grounding out were in place but i hadn't checked anything else on them ill prob just go ahead and strip them out again and just completely re install them and check the leads to make sure they aren't damaged inside the case grounding out somewhere

funny that all makes perfect sense, little things always seem to escape me when ive been staring at them for too long

Thanks again guys this one has been killing me, ill try and remember to post a follow up

Brandon
 

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How is the coil wired to the 2 sets of points? If they are wired in parallel to the same coil primary terminal then one set of points will always remain closed while the other opens so it will never see the points opening.

Normally there are two coils and 2 sets of points - essentially 2 separate ignition systems. I can't see how separate points could work with the dual lead coil. If you are running electronic ignition then you could do it though.
 

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Discussion Starter #6
with a dual lead coil you run both sets of points wires together to the same lead on the coil with a single condenser , its an HD coil set up , first time ive done it but its one of the more widely used wiring schematics, ive seen allot of folks run em that way on older trumps, theres a few diagrams for it as well
it just fires both pistons at the same time so ive been told as far as the difference in performance
 

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Well I understand the wasted spark concept. I am doing the same with a Boyer and Accel dual tower coil. In thinking about it more I guess it all depends on the points cam lobe. If it keeps the points open a long time (a little more than half a camshaft revolution) then wiring the two points together in parallel would work. Evidently it does :)

Will try find my old advance unit out in the garage and check it out. Sorry about the added ball of confusion.

Russ
 

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Discussion Starter #8
no worries, i think the only thing you have to actually do to the points for that is open the gap a little wider for example my stock gap is like .014 - .016 with the dual lead i have to run .020 but otherwise works great.. at least for the brief laughing moment this dirty trump gave me spark .. just before she decided to turn and makes me work for it haha
even had a little bit of combustion for 2 kicks ... just enough to get me frustrated .. ha.

hopefully ill make some headway after i get out of work tonight though
 

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with a dual lead coil you run both sets of points wires together to the same lead on the coil with a single condenser , its an HD coil set up , first time ive done it but its one of the more widely used wiring schematics, ive seen allot of folks run em that way on older trumps, theres a few diagrams for it as well
it just fires both pistons at the same time so ive been told as far as the difference in performance
This will not work. and is your problem. Toprove it, remove the connection to one of teh points and try to start it. It will run on one cylinder only. Somehow you need to wire the points in SERIES, not parallel. search the web for a diagram of series wiring, parallel wiring.
 

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Discussion Starter #10 (Edited)
Yea .. well i went over my points again and found where they were grounding out at , the condenser for whatever reason was grounding out which was grounding out both points wires so theres that ....


Makes sense Panda .. here's were i got the diagram ive been using thats "supposed to work "

http://www.jockeyjournal.com/forum/showthread.php?t=41493&page=4

I know the hd dual lead can be used and mine is wired to the diagram in that link but yea either its missing something or i am, im going to change out the condenser regardless , i tried the test on it discharged it first and tried to see if it would build a charge and nada nothing zilch ...

this is my first experience with points and while ive heard allot of good things about them being easy to work on when your on the side of the road ... electronic ignition is looking better and better

Thanks for the info looks like its time to get to the bottom of this dual lead set up ....


Brandon
 

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Yea .. well i went over my points again and found where they were grounding out at , the condenser for whatever reason was grounding out which was grounding out both points wires so theres that ....


Makes sense Panda .. here's were i got the diagram ive been using thats "supposed to work "

http://www.jockeyjournal.com/forum/showthread.php?t=41493&page=4

I know the hd dual lead can be used and mine is wired to the diagram in that link but yea either its missing something or i am, im going to change out the condenser regardless , i tried the test on it discharged it first and tried to see if it would build a charge and nada nothing zilch ...

this is my first experience with points and while ive heard allot of good things about them being easy to work on when your on the side of the road ... electronic ignition is looking better and better

Thanks for the info looks like its time to get to the bottom of this dual lead set up ....


Brandon
So how would you repair an electronic system?
I have a feeling if you were to wire in electronics wrongly they might not work any better than wrongly wired in points. The usual 'cure' for tehis a a big bore kit and a bigger battery.
In my opinion 90% of points failures can be directly attributed to bad maintenance.
sort out the bad ground, then try to start it with only one set connected. If that works (on one cylinder) connect both sets. If that does not work, you have the wrong kit. I cant for the moment see how you can in fact wire the both sets of points in series, because I think the base plate is grounded. You will need to get two coils, and wire them separatly one to each set of points.
 

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Discussion Starter #12
oh my comment about wiring in electronics is just my frustration with points which im new to ..

however i did find a flaw in the left point the metal that wraps around the plastic housing where the wire attaches flared out too much on the end causing it to hit the mount screw ever so slightly when it was tightened down with the nut grounding everything out , turns out the condenser was fine i hooked everything back up the way i had it key switch and all and after a few kicks and some starting fluid to help out she fired right up both points wires are still wired together going to the coil , not sure how it works honestly but it does killed it cranked it several times no problems getting spark and compression in both cylinders so however it works it does indeed work i can attest to that

thanks for pointing me in the right direction tho i never would have thought to check the brand new point itself that was just installed for having a flaw in the metal spring ... but hey its a triumph right .. ha

if you want some more specifc info on my set up lemme know and ill try to get as many specifics for you as i can , if you'd just like to see why this set up works i don't really have any idea myself wiring is def not my forte

Brandon
 

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I couldn't find my old AA unit in the garage pile so I found this pic of one (Triumph/Norton) on the 'bay.

If you zoom in on the cam profile I think it looks like it would still be holding the second set of points open while the first set opened and so the coil would fire.

This might work. I agree with panda that disconnecting one set of points to see if it runs on one cylinder would be a good way to test out these ideas as well as the rest of your wiring.


 

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...
this is my first experience with points and while ive heard allot of good things about them being easy to work on when your on the side of the road ... electronic ignition is looking better and better
Points are ludicrously easy to work on since they're as simple as it gets, and easy to troubleshoot, I think your primary problem is trying to use some stuff that doesn't quite fit the application, maybe the coil is somehow unhappy with the way the points charge it up.

The wiring diagram you linked is accurate. Even if you could connect points in series (it would require a bit of re-engineering of the whole assembly), it wouldn't work. For each two revolutions of the engine, the cam will rotate once, causing the eccentric to rotate once. One point will be always be fully open (no spark) as the other one is is fully closed (sparking). That means that there would never be a spark when it's most needed near the apex of the compression stroke due to the circuit being open. You want both cylinders to fire any time the pistons are near the apex of the compression on a twin like this. That means anytime one point is closing, you want sparks (once every engine revolution, twice for a cam revolution). Parallel wiring does accomplish this.

Hopefully you'll be fine after replacing those condensers, that's certainly one of the cheaper, easier problems to correct.

Scott
 

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Discussion Starter #15
its sorted out now ... the metal on the point that the points wire gets attached to had a bit of a flare on the end where it wraps around the plastic housing and it was making contact with the head of the mounting screw that attached the point to the plate , a bit of grinding took care of it and now she fires right up no issues both cylinders are firing now im off to get the amal adjusted properly and a few other odds and ends and she should be on the road in no time


brandon
 

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Brandon glad you got it going. Yay! The electronic ignition thing is controversial. I've been running the same Boyer for 34 years and it hasn't let me down yet. Points are simpler and can be fixed so you can make it home but I just hated the darn AA unit problems and finally gave up on it. They wear. They stick. This affects the engine coming back down to an idle reliably.

I switched to an Accel dual lead coil about a year ago then got a Dyna coil as a spare. Both look and work about the same except one is yellow. One thing to watch is the engine dying in the rain. The sparks are so powerful that they came right thru the brand new coil tower boots when it rained. I had to goop them with silicone caulk under the boots which has worked out fine even when I've gotten caught out in some hellacious downpours.

Scottm if I understand you correctly I'm sorry to disagree with some of it. The spark occurs just at the opening of the points not the closing. A series hookup could work if the points cam was a different shape than it is. It would need a narrower lobe like a valve camshaft. You would get the 2 sparks per cam revolution.
 

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I am glad you got it working now. The plastic washer area is aplace where problems can occur. Another thing to watch for is after 40 odd years or so dirt and rust cab short outthe stem from underneath, often intermittently giving all sorts of wiers firing symptoms. The cure is to clean outthe mechanism every 20 years or so. If you do this more often, say ever five years, you could just lubricate the advance mechanism. :)
especially the pivot points with molygrease.
 

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Good to hear you got it running, Brandon!

Scottm if I understand you correctly I'm sorry to disagree with some of it. The spark occurs just at the opening of the points not the closing. A series hookup could work if the points cam was a different shape than it is. It would need a narrower lobe like a valve camshaft. You would get the 2 sparks per cam revolution.
I think you didn't understand me correctly, the bit in parentheses was the big thing-- it would require substantial re-engineering of the whole points setup on the Triumph to accomplish.

I did misspeak (too many revisions while I was changing my mind about how I was phrasing things)-- my main point was that I don't think there's any overlap between the stock points being closed (if they don't close, the coil doesn't get its field charged-up).

Theoretically, even if there was overlap because the points spent almost all their time except for a brief blip closed (which I don't think is the case, I should look next time I have the points cover off), the time they were closed would be far too short of a duration to get a strong enough field going in the coil to produce a strong spark (it would most likely create 4 rather weak sparks with a gap in the middle when the opposite point was fully open). The eccentric would have to be changed dramatically (more to an ellipse even) to make sure there is comfortable overlap where both are closed and the circuit is complete and to get rid of that second blip of the points both being closed. No point in wasting THAT much spark! In addition, since the points share the ground part of the circuit by design, at least one would have to be isolated completely from ground and wired to the other in order for a series connection. That would seem to be an impractical mod, I can't think of a situation where that would really offer a substantial advantage over a parallel-wired wasted spark system, since the result would be largely the same, and any mods made to a parallel setup to optimize spark would be simpler. Though if you have a chance to explain a situation where series would be more desirable than parallel, I'm all for broadening my understanding!

Engine theory is fun. :D

Scott
 

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Scottm - Yes there is no reason to ever go to a series setup and the massive re-engineering would be of no benefit that I can think of anyway. I was surprised at the shape of the stock points cam - that it keeps the points open so long. So it was good to learn something out of all this and Brandon even got his bike going.

Panda I maintained my autoadvance unit religiously but it sure didn't make it any 20K miles! The advance slots were elongated - more like pounded to death (which no amount of lube could help) after about 8K miles. I was doing a lot of around town driving in the '70s so that probably was a factor. The throttle was more like an on-off switch back then!
 

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Scottm - Yes there is no reason to ever go to a series setup and the massive re-engineering would be of no benefit that I can think of anyway. I was surprised at the shape of the stock points cam - that it keeps the points open so long. So it was good to learn something out of all this and Brandon even got his bike going.

Panda I maintained my autoadvance unit religiously but it sure didn't make it any 20K miles! The advance slots were elongated - more like pounded to death (which no amount of lube could help) after about 8K miles. I was doing a lot of around town driving in the '70s so that probably was a factor. The throttle was more like an on-off switch back then!

I find often I seem to have had an entirely different experience with Triumphs than many others.
My first bike I was fortunate to have rebuilt by a very good mechanic three weks after I innocently bought a heap of junk. It was 1959 Tiger cucb. After the rebuild it ran faultlessly for about two years doing about 400 miles aweek ( often more ).
I then traded it in for nearly new 1961 Speed twin 5TA, foolishly at 20K miles I decided to hot up the engine and remove the panels to make it more sporty. That bike did another 70K miles and only had me stopped bythe roadside once. A bad batch of clutch hubs ( from Qualcast) failed and threw the primary chain. I used it to commute 435 miles each way each weekend. Never had any electrical failure on any bike until this year when my BMW died on the way back from Italy.
I maintained my bikes and do not expectthem to fail on me and it did not. The key to these bikes is that they are simple, but even so you still have to know what the adjustments are for. They do need regular oil changes. I have seen many times bikes that wont start assembled with the plastic insulation missing. They are simple and hence simple to get right if you care to learn what it is they want. Unlike modern 'white goods' bikes which tend to work flawlessly until they have a catastrophic failure. Almost always you will have warning of an impending failure. I suggest you monitor regularly your mpg. That is nearly always the first measurable thing that can alert you to something going off test.

Re points, i would always advise you get a cdi ignition system that uses the points to trigger the unit. They only pass a few milliamps at the points so the points typically last 35/50 k miles ( until the fibre wear tab wears). In the event of a problem. You just need to change over three push fit connectors and the system is back to normal points operation.
 
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