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Discussion Starter #1
Evening all,

The Bonnie has developed a new issue; occasionally when I pull up at a junction, she stalls. Once kickstarted again (which may take a few tries) she will tickover perfectly well and off we go. She might be ok at the next junction but she might not, it's a lottery...

Now, this seems to coincide with the point when I replaced all the control cables, as I didn't have this feature before (at least when she was warmed up). To do this I removed the flat bar that braces the carbs together, removed the fuel banjo on one carb and loosened the clamps on the large rubber pipes that connect carbs to head. This allowed me to rotate the carbs outwards so that I could remove the carb tops, without removing the carbs themselves. I replaced the throttle and choke cables, put everything back together, then carefully set the carb-top cable adjustments so the slides were perfectly in sync and refitted the air filters and air box. I also adjusted the choke cables so both had exactly the same small amount of play to ensure that when the choke was off, the plungers would seal to the enrichment circuit (even with the handle bars on full lock) and that they would both move at the same time with the choke lever. So, all should be as it was before, but I now have the stalling issue.

This is almost definitely fuelling. Apart from the fact that everything on the ignition side is new/high-quality stuff, she splutters when she stalls (as though she is running out of fuel) and occasionally I can catch the stall by feathering the throttle. I have tweaked the idle speed a little higher (around 1100rpm) and adjusted the mixture screws to 1 full turn out from the point where screwing them in starts to drop the idle (which is around 2.25 turns out from fully in). This seems to have reduced the problem a little but she still splutters a little at some junctions and a little less occasionally than before, still stalls.

Any ideas please? What could have changed?
Ian
 

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First, I’ll tell you I don’t believe in coincidence , so something you just did has changed the hot idle . Second, I’ll tell you they still happen whether I believe in them or not. You sound as if you’re pretty meticulous, but anyone can miss something. Make sure your carbs are level, and spray starting fluid around the manifolds while idling to check for an air leak. Make sure the carbs are properly seated in the manifolds and that you didn’t overtighten, creating an air leak. I would remove the mixture screws and spray some carb cleaner in each, just to be sure something isn’t plugging the passage. I would run some carb cleaner through the fuel system. Are you sure you have adequate fuel flow and you didn’t kink a line when you moved the carbs around ? How old are your spark plugs ? Might they be due for a cleaning or change ? Make sure the spark plug wires are ok and plugged in well on the caps and coils. If you have a spark checking gadget, use it. If you’re not getting consistent fire on both sides, find out why. Do you keep the bike on a maintenance charger ? They dont generate a lot of juice at low rpm and a charged battery will help them run in stop and go traffic. I run my idle around 1200 rpm.
 

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I’ve had problems stalling in traffic, but when the temperature is really hot and so is the engine. I have fairly worn out Amal’s, so I know thats part of it. When I had the problem I was parking outside and getting a little moisture in the fuel that collected in the float bowls periodically. I’ve loosened up my valve clearances a bit, and installed a Podtronics regulator with the built in capacitor. We’ll see.
 

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Discussion Starter #4
Thanks for the reply. Checked all that out last night and there is nothing obvious but left the battery charging. The strange thing is this only happens when I come to a halt. I can pull the clutch in whilst riding and she settles to a stable idle as I freewheel along but pull up at a junction and she stalls.
 

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Thanks for the reply. Checked all that out last night and there is nothing obvious but left the battery charging. The strange thing is this only happens when I come to a halt. I can pull the clutch in whilst riding and she settles to a stable idle as I freewheel along but pull up at a junction and she stalls.
Hi Boggie
It seems to me that the only difference between pulling the clutch in while riding and coming to a halt, is the brake light is on during coming to a halt.
I am wondering if the battery is low, or you already have reduced voltage at the electronic ignition through poor connections, that putting the brake light on drops the voltage further.
Low voltage on an electronic ignition tends to advance the spark, maybe to the point that you are losing power at tickover.

You should have a 3 phase alternator fitted as standard equipment on a 79 T140E.
If you lose one connection or diode in the rectifier you are left with low a single phase output. Enough to run the bike without lights, but not enough to keep the battery charged.

I think I would be tempted to confirm the voltage at the electronic ignition supply point, with and without brake light on.

There is a small chance that this is the problem, but it is easily testable to eliminate it from your enquires.

Regards
Peg.
 

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You know, this occurred to me too. I was thinking seriously of installing an LED taillight bulb . Obviously if you have an electrical issue that should be addressed first. The lower draw may be enough to keep the bike from stalling if insufficient current is the problem. $20 but if it stopped the bike from stalling at lights it would be worth it. I’m putting the Podtronics on with the hopes of charging my battery better. If it does stall I’m hoping the capacitor will help it start better when I’m sitting there in 6 lanes of traffic !
 

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Discussion Starter #7
Oooh! You might ave nailed it there and charging was something I was suspicious of. I was thinking of replacing the charging system, ideally with the best available / highest output option in the future. It is on the list of potential areas of improvement that I would inevitably pick the collective Rat forum brains for candidates. As a cause of my recent stalling issues this potential suspect makes a lot of sense for the following reasons:

I always ride with my headlight on. It gives the Volvo divers something to aim for.
On my recent ride with headlight on, the indicator lights (neutral, oil etc) were rather hard to see. I had initially put that down to bright sunlight.
I generally brake at junctions, so there will be additional 21W of demand upon the battery.
I hooked up my "intelligent" charger last night and was expecting to come down to a fully charged battery in the morning. However, whilst admittedly in "recondition Mode" (which adds an extra stage to the process) it took until early this evening to complete the cycle, i.e.20hours. So, this seems to indicate that the battery was rather low...

I will take it for a ride tomorrow to see if the fully charged battery has resolved the issue and measure battery voltage Off, running and running with lights. Will report back, thanks!
 

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You can get approx. 300km highway/country riding [I've done 340km but it was missing by the time I stopped] with a healthy/good battery and no charge if you don't use your headlights indicators or brake light. It was illegal, but I disconnected the brake light switch so I could use my brakes....but I was in the country and careful not to brake suddenly with other vehicles behind me.

So I'm thinking that your battery is either not getting a charge or is 'past its use by date'.
 

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Hi Ian,

I was thinking of replacing the charging system, ideally with the best available / highest output option
I hooked up my "intelligent" charger last night and was expecting to come down to a fully charged battery in the morning. However, whilst admittedly in "recondition Mode" (which adds an extra stage to the process) it took until early this evening to complete the cycle, i.e.20hours. So, this seems to indicate that the battery was rather low...
Mmmm ... ime, that's more-likely the battery turning up its toes, less-likely a charging system problem. Do you have the kit to load-test it or do you remember the quick-'n'-dirty 'load test' from an earlier thread?

Your bike originally had a 3-phase stator as standard (individual wires out of the black insulation out of the primary are White/Green, Green/Yellow and Green/Black), albeit the 'low-output' version (10.5A/120W @ 5,000 rpm, 85% @ 2,400 rpm), 3-phase square plate rectifier and either a single Zener across the battery or a strip of three, one connected to each alternator phase.

When Lucas developed the 3-phase alternators, afaict it was primarily to address the increase in requirements and desire to ride lights-on all the time even at low engine rpm since the succeeded RM21 and RM23 had been developed. So there wasn't any increase in the rated Amps @ 5,000 rpm over the previous single-phase, just an increase in percentage of rated at lower rpm. I'm not saying the high-output 3-phase isn't a nice-to-have, just be careful you aren't treating a symptom of a fault or PO change elsewhere?

It's possible the rotor has lost enough magnetism if the PO left it out of the stator or keepers for a long time while he did the work on the engine. I'm guessing you know how to check for DC Volts rising with engine rpm and stator Amps with either an AC Ammeter or a load resistor and AC Voltmeter? If not, I'll be pleased to run through the processes.

Digressing slightly, absent failing components, the only substantial improvement available is a high-output (14.5A @ 5,000 rpm) 3-phase stator; if you bike has a single Zener, you'd also need a reg./rec because the 'three Zeners' strip is NLA.

I always ride with my headlight on.
On my recent ride with headlight on, the indicator lights (neutral, oil etc) were rather hard to see.
I generally brake at junctions, so there will be additional 21W of demand upon the battery.
As I say, when Lucas developed the 3-phase alternators, it was primarily to address the increase in requirements and desire to ride lights-on all the time even at low engine rpm. So your bike shouldn't have a problem, bar a fault (assuming you aren't chugging it around like a Hardly? ;)).

By the time the Co-op built your bike, thankfully they and Lucas had finally given up on the execrable BPF bulb and lens/reflector; :doublethumb your bike originally had a 45/40 P45t bulb and decent lens/reflector - the bulb hasn't been changed for either a 60/60 non-qh or a 60/55 qh?

Because the (original) lens/reflector is so good at focussing the headlamp light, fwiw when I dispatched and commuted on Japanese bikes that used the same bulb, I fitted them with a 20W quartz-halogen pilot bulb and used that around town - lower current draw and a wider spread of light; other road users are more likely to see it before they're directly in front of the bike? That said, those q-h bulbs aren't so easy to get these days, and others have posted on forums that they don't last too well on 'big' twins; if the headlamp bulb is correct, maybe consider the suggestion that @rambo has posted a few times, of a 10W or 20W Eagle Eye LED in place of the pilot bulb and holder?

Hth.

Regards,
 

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Discussion Starter #10
Thanks All,

After a full 24h charge, I took the Bonnie for a ride with the headlight off. No stalling issues at all! Now I just need to find time to see if this is the battery or the alternator. I have all the test kit I need but have not had the day-time to look.I can't run the bike in the evenings as with 1.5" headers and straight-through Norton pipes it is rather loud and I don't generally get back from work until kids bedtime. :)

So I hope to get a chance this weekend to get her up to temperature then measure the charge voltage at various RPM and load-test the battery. The battery is fairly new (late last year) and according to my "intelligent charger" the battery is good but I have a proper battery analyser / load tester that gives comprehensive reports on battery performance and life expectancy etc so I will get back to you.

I would potentially still be interested in fitting a higher-output alternator or perhaps LED main/dip bulb if there is one suitable for these old girls...

Ian
 

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Hi Ian,

higher-output alternator
TMS - http://www.tms-motorcycles.co.uk/store/products/list.asp?cat_id=143:-

. "Code" 47244/UK (47244 without the "/UK" is Wassell) is the stator;

. if the existing rotor is badly-demagnetised, "Code" 54202299/UK (again, without the "/UK" is Wassell);

. "Code" VR.10124/P is the Podtronics 3-phase reg./rec, Podtronics have been around for decades;

. or an Aussie on BritBike has been using and recommending https://www.ebay.co.uk/itm/1pcs-Car-Voltage-Stabilizer-Regulator-Rectifier-For-Honda-VT125-250-VFR400-750/192941074220 plus https://www.ebay.co.uk/itm/Motorcycle-Voltage-Regulator-Solid-Regulator-Rectifier-for-Honda-CBR-UK/173951668097 for nearly ten years.

LED main/dip bulb
Regrettably, afaik there isn't specifically a P45t LED bulb, all that's available is an adapter for a P43t; :( if that's what you wanted, imho change the lens/reflector for one that takes the P43t bulb.

Hth.

Regards,
 

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My first Triumph was a ‘67 TR6-R with no battery, capacitor, and an Amal Monobloc with a worn slide. It rarely stalled at stop lights. It started right up. I rode it at night, every night, on the way home from work. Why do they stall at idle now ? Is it ethanol fuel ? No, because I use non ethanol quite a bit and though it runs better, it still stalls. Old rotor or stator ? The electrical system on the ‘77 was supposed to be better than the ‘67, correct ? But I know it’s old. My ‘67 was only a few years old when I rode it daily. My stock concentrics seem to be in decent shape physically. Should I bite the bullet and buy some Premiers ? Will that fix my stalling ? I just installed a podtronics with built in capacitor but haven’t run it yet. Maybe that and an led tail light bulb will do it. .
 

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After 10 years of constant worry about quality and quantity of charging in my A65 used with lights on all the time I decided 3 phase high output alternator is only solution for my Trident, and it is.
No more problems, no more observation of voltmeter no more worries, the charge is always good, light are always bright case closed.
 

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Discussion Starter #14
Mmmm ... ime, that's more-likely the battery turning up its toes, less-likely a charging system problem. Do you have the kit to load-test it or do you remember the quick-'n'-dirty 'load test' from an earlier thread?

,
Alas, in my case it appears to be a supply and demand issue that the alternator is failing to meet.

I ran my battery tester on the 6 month old Yuasa. It came up with a better than spec result of 117A CCA and reported battery life at 100%. Next I hooked up my Fluke for a reading (12.65v) and then started the bike. Here are the readings, with headlight off first and on second:

1000rpm 12.2/11.9
2000rpm 13.6/12.1
3000rpm 14.2/12.2
4000rpm 14.3/12.3

These figures do not include brake light (currently on my bench) but as this is roughly half the power of the headlight we can assume the voltage will drop a further 50% on the difference in the figures above. i.e at on the road rpm the voltage would be well under 12v and I hear the Boyer does not like this.

So, it appears that either I need to fit LED H4 and stop/tail lights OR a better alternator CW new rotor (just in case)

Ian
 

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Battery Related : My Busa wouldn’t start but the battery read between 12.6 - 12.86 after being hooked up in the bike all night on no charger. If hooked up on a maintenance charger it would read 13.1 v . The battery was bad and wouldn’t even honk the horn, just a faint clicking from the solenoid. My “ smart “ charger said the battery was full. A second smart charger, same brand, said the battery was defective. It was right. I’ve never seen a battery read that high and be bad before.
 

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Hi Ian,

Next I hooked up my Fluke for a reading (12.65v) and then started the bike.
Mmmm ... but what are the meter readings ignition-only and ignition+lights before starting the engine?

appears to be a supply and demand issue that the alternator is failing to meet.
Why only the alternator? Does the bike still have the rectifier? If so, why not one or two diodes gone? Otoh, if the bike has a reg./rec., a fault in that?

either I need to fit LED H4 and stop/tail lights OR a better alternator CW new rotor (just in case)
If the problem does turn out to be the alternator, why would you fit an LED bulb? Not going to make the alternator any better and, when you do have to replace the alternator, you have a ridiculously-expensive headlamp bulb you don't need? :confused:

Hth.

Regards,
 

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Get a 1 ohm resistor and follow the procedure in the workshop manual to test the alternator and rectifier. It's the best way to figure out which is faulty. All you know now is the charging system is below par, but you don't know where the problem is. I thought I had a bad alternator until I tested it, turned out to be the rectifier which was really cheap to replace with a modern one. One ohm resistors are easy to find at electrical supply places online.
 

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Hi Boggie, I don't know anything about the 3 phase system. But my bike was doing similar with the charging. No load was acceptable, with lights on, very bad.

Bike was charging good the ride before. 40/50w stock headlamp. I didn't think magnetism in rotor was lost in 1 day. Battery was 5 years old, but did ok on load test, not perfect. I got a new battery. No change. Still bad. New battery went down on 200 mile ride like old one did. Since battery was aged I decided to replace it. I didn't really think it was problem though.

I don't like throwing parts at bike as a diagnosis tool. Costly & I want to know what went wrong. Remember every connector & every inch of wire must be examined, including fuse & fuse holder.

I decided to do the full factory test. The first step is install a known good battery, which was one reason I got new one. I tested the new battery by leaving head lights on motor stopped & timed the voltage drop at battery terminals. The new battery was indeed stronger.

1 ohm resistor to test alternator are not so easy to come by in 200w & not cheap. So I didn't test alternator at its wires.

Reading the rectifier test in manual, they are basically putting a load through diodes to test passing & blocking.

Disconnecting all wires from rectifier I used an ohm meter to do a quick test of diodes. 1 was open circuit both ways.

To test with ohm meter, disconnect all the wires. Then put one probe on disc, the other on the next disc that wire is soldered to. Make sure probe penetrates paint so you are on the metal. The disc has the cathode end of diode bonded to it in the dome where the wire goes straight in. You can't see the diode, it' very tiny inside the dome, but you know the diode is inside the tiny dome on disc. The other end of wire is the Anode. This end of wire is pushed through a tiny hole in disc, bent over & soldered. The idea is to test just one diode at a time. There are other ways, but this shows you which one is bad, if any. With red lead of meter connected to the disc that wire is soldered to, the black lead to the dome of the diode the meter should read some resistance. When you switch leads on discs the meter should read open circuit or very near to open circuit.

It's possible to have diode short & read both ways, but I find most often the diode goes open circuit when it fails. Upon very close inspection my bad diode looked different like the paint had gotten hot.

I removed rectifier & bench tested using a 21w light bulb as a load & the new battery. I volt dropped each diode current flow as I wanted to learn how much loss each would have. The test showed the same result. 1 diode open circuit. I had expected this, but wanted to verify under load of the 21w bulb.

I took old rectifier apart & found the diode had delaminated from the disc.

The rectifiers are fragile if roughly handled, but not so flimsy as shop manual suggests. The skinny connecting wires are strong & well solder to the copper discs. The weak part is the diode is bonded to the dome in disc. I experimented with one of the good disc/diodes & it took a fair amount to break it out.

There is no internal connections to break in center of discs. There are plastic spacer/insulators washers & sleeve. The center bolt does have to be electrically connected to some discs though. If the nut works loose & the discs rotate, the connections can be compromised, but not hard to tighten & correct. A poor connection here will cause low voltage to charge batter.

To tighten remove rectifier, Put the bolt head end in vise. Counter hold the discs with one hand & tighten the nut with the other. The idea is don't let the discs rotate amongst themselves & pull a diode loose from disc. Of course always test the diode with at least an ohm meter to verify it still works.

I got a used rectifier from eBay $15.00. Seller said it was good. It had a very rusty center bolt, but all the diodes tested good with ohm meter. I volt dropped using the 21w bulb & found both end discs were not making good contact with center bolt. I found the ends were corroded upon removal of bolt. Nothing really falls apart, but the spacers will fall out so memorize their positions. There is a little flat washer like a shim, so keep an eye on where it goes.

After installing the cleaned up used rectifier, charging system was back to being good. I tested the Zener also per shop manual as I have an inline amp meter. It was within the spec in shop manual.

Certainly nothing wrong with just getting a podtronics rec/regulator if that's what you want. I want to keep my bike stock as practical. On my bike new rectifier + new Zener was same cost as podtronics. So $$ wasn't an issue. I just wanted to keep it stock.

My advice is test the old rectifier & see what you get. If it fails, then decide on going electronic or not.

After repairs I did much road testing & bike was back to how it was when new. I live in city so lots of stop lights etc.

It is foolish & will leave you walking to not properly repair your charging system. A band aid of LED bulb is only going to cost you a tow bill & other problems.

Once charging system is back to how it was when new you'll be good I think.

For users of the older 2 wire alternators once they are up to what their spec was (not much) then the band aid of LED bulbs can have some usefulness if you don't want to upgrade to 3 phase.

The LED headlamp bulbs BPF I have some experience with. For sure they will save a lot of electricity. The old versions put out very poor beam focus so I went back to the old 414 bulb. The newest BPF with 8 LEDs puts out a decent beam & consumes the same electricity as the old version LED. I also put in LED instrument bulbs. Normal 21/5w stop bulb.

Without question the LED headlamp bulb has allowed me to ride much, much longer in city. Not an issue with 3 phase, but 2 wire alternators city riding they just cannot keep up. In practice with the LED bulbs I installed it's practically like riding with head lamp off.

Your reflector type will make a difference of course, but the new version LED BPF to my eyes is 1/2 again brighter than 414 bulb. Still not that bright, but at least better. Swapping bikes & doing experiments looking at bikes from a stop sign, oncoming, them following you the LED makes the bike many times more visible. This might.... save a collision from car pulling out from side street.

Again my '73 Tiger single phase 2 wire alternator is not the same. My rectifier has less discs, but the odd voltage differences with lights on/off is similar to a degree.


Here's a link to that thread.

https://www.triumphrat.net/classic-vintage-and-veteran/952978-rectifier-anybody-take-one-apart.html
Don
 

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My thought on the stalling at stop lights : The last thing I did before the bike stalled was turn on the brake light ! Could be a coincidence, or maybe that little bit more draw was too much ?
 
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