Britbike forum
Really need your help guys. Put in a new Boyer Mk IV analog box to replace the failed Mk III. Now the bike has spark when push the starter button and look at a spark plug taped to the head but bike still won't e-start but will kick start because I notice voltage drops to 10 when pushing the starter button. Tried another super battery and no difference. I thot before spend $ and time to replace the wiring, check and clean starter connections and clean inside of starter motor. Did not realize could easily remove 2 studs and clean starter (which i eventually did after messing things up, it was pretty clean and did not really need attention). I thot I had to remove the starter/solenoid unit. Shop manual says "remove 3 screws" (assume around the circumference of the starter). Guy who replaced the solenoid left out the bottom one so only 2 allen screws to remove, which I did But an article in Triple Echo says also a fastener inside the oil breather area, I removed my breather filter and only see smooth metal under there, no sign of any bolt or nut head. Could not get the unit off, hammered away at it, even stood on the starter. Tried hammering with a big slot screwdriver from the left side where there was a tiny lip but just destroyed the lip. Putting a claw hammer under the starter can lift it up a tiny bit, Local Hawg shop guy thinks the guy who replaced my solenoid a few years ago used some super strong gasket goo. Out of desperation I removed a bolt which turned out to be the solenoid plunger. Big mistake! I heard a click, it did not want to go back. Once the starter was cleaned I wanted to test the bike and see if still big voltage drop. Fastened everything back and this time was able to screw the plunger bolt down. Big test: Oh, oh, the starter only clicks at the solenoid. (battery still 12 v) Plus, when i kick over the bike there is a strange clicking sound. I removed the plunger and it made it worse, felt resistance while kicking and more noise. What to do? What have I done? What to do about the strange noise and the plunger? If i have to remove the starter/solenoid unit are there just the 3 screws and will applying heat help?
You really should look at the parts manual to see all the bolts, nuts and screws. There are three screws that hold the screws that hold the starter to the solenoid housing but you do not remove these if you are taking off the whole assembly. You have to go through the breather box to get to the solenoid screw and bolt.The breather box is the cover on the primary side held by five 1/4" screws. There is one screw (19) and one nut (25) holding the solenoid.
You probably removed the throwout pivot bolt. You have to remove the whole starter assembly to replace it.
Hammering, prying, standing on it just destroys parts.
I did look at the parts book and service manual but they were useless compared to your sage advice. Thanks! BTW are you perchance the same Dave Madigan that sells the replacement starters, do your starters draw less power than the Lucas? In other words would this solve my voltage drop problem?
Hi Randy---I had a similar experience with a T160 I bought several years ago.
It had a Boyer Mk III fitted and would not start although it had sparks at the plugs with the plugs on the head.
Thinking it was the Mk III not performing with lower voltage when starting I replaced the Mk III box with a MK IV box. No difference.
Thinking I had better check out the starter motor I took that off, dismantled and cleaned it---although it was pretty clean. No difference.
I was talking to a friend who used to be National Service Manager for Ducati North America and he told me that they had similar problems that were solved using special high purity starter cables from motoelectric in San Francisco. So I got a set of those and fitted them. No difference.
I then thought that maybe it was because the Boyer ignition was powering 6 volt coils so I bought 3 4 volt coils and fitted them. No difference.
Feeling pretty discouraged but determined not to be beaten I splashed out on a Trispark ignition (the one with the separate electronic box).
This needed 12 volt coils so I bought 3 12 volt coils.
Fitted the Trispark and the 12 volt coils.
Turned on the gas, set the chokes and --I swear--the engine started just before my thumb hit the starter button!
So--that was my experience--it may help you along the way.
Yes, I sell replacement starters. Mine are 1.4KW. I am not sure of the Lucas rating but they use field coils so might draw more power. Mine have a planetary gear reduction. The Lucas has a single internal gear.
I found jumper cables are a cheap source for starter wires.
Check the ignition using a battery separate from the starter battery. If that solves the problem then low voltage is the problem. If the Boyer uses separate power wires for the coils and electronics there are voltage booster circuits that can be used. Another possible solution is to use the Lucas battery eliminator capacitor with a diode before it in series and have that supply the Boyer electronics. The capacitor will keep supplying the Boyer as the voltage drops from the starter.
Thanks to Dave I found the hidden bolt and the starter/solenoid unit came off as easy as pie. I was looking for the mystery bolt down the oil breather filter round hole, whereas you have to remove 4 screws from the alloy breather cover and look across to the far Left.

Hi Tridentman, thanks, your experience was so much like mine I thot I was reading my own post. I am using a new Odyssey 545 battery and also tried a year old model 686 that I use on my Guzzi to no avail. Like you I replaced the Boyer Mk III with a IV and it made no difference. Cleaning the starter (it was already good) made no diff. I was thinking of the 4 v coils but based on what you said I won't try that or the "high purity" starter cables. I was going to go Tri- Spark as a last resort but due to COVID effect on my income since March cannot afford it. So I will try Dave's proposed fix and also check my wiring for voltage drops as per factory service manual.

Q for Dave Madigan: I can buy and install the capacitor where it shows it can be on the stock wiring diagram as an option (between battery NEG and the Zenor Diode) but what specs for the diode? Are you sure this will work in conjunction with the Boyer? (The only electronics I know was from High School back in 1965)
I do not have any experience with the Boyer but reports say the analog version is sensitive to low voltage and 10 volts is the minimum. You have to do the secondary battery test to see if that is the case with yours. If so you may be able to fix the problem if your Boyer uses separate power leads for the box and coils. Putting a diode in series with the Boyer power lead and a capacitor across the Boyer power leads with give it reserve power when the starter is used.
I suggested the "battery eliminator" capacitor because they are readily available and conveniently mounted. You only need a general purpose diode like a 1N4001. You can solder it into th power lead to the Boyer.
Thanks so much,
So I install the capacitor where the optional one goes (between Battery NEG (since its a Pos ground system) and the Zenor Diode,
and I mount the new diode by splicing into the white wire which connects the ign switch to the Boyer box?
FYI, the analog Mk III and IV Boyer boxes only have five wires coming our of them to hook up: Call them A to E:
A to + (POS) of coil #1 which also runs from there to Batt + which runs to ground.
B 1 to - (NEG) of coil #3,
C and D to where the CB points used to be.(distributor)
and F to the ignition switch.
So not sure what U mean by "across the power leads"
BTW I checked the wires and cables between relay and solenoid and solenoid and starter and none were high resistance, I have a multimeter and lots of batteries but did not know how to do a proper test so I simply doubled up each wire or cable one at at time with a fresh wire to reduce any resistance but it made no difference. (Also replaced the cable that goes from battery to solenoid) Wondering if a 2 v drop is normal for these bikes.
So F and A are the power to the Boyer box. Before you try the diode and capacitor, use a second battery between the F and A Boyer terminals and connect the +Battery to your secondary +Battery. That will tell you if voltage is the problem. If it is then connect the capacitor between the F and A leads of the Boyer and put the diode between the ignition switch and F lead.
Thanks, my alphabet was wrong, was tired, there's only 5 wires to/from the Boyer, so I meant E not F but to avoid confusion let's keep calling it F (the white and blue wire or white & yellow wire that runs from Batt NEG thru ign sw thru kill sw to the ballast resister (removed when using a Boyer) to connect with the white Boyer wire ) must be input power to Boyer,(last test shows 13.9 v when starter is not engaged).
I assume B (black) is the Boyer output as it goes to far Left coil NEG terminal. Last test showed it has 12.4 v at that terminal when ign on and no starter, telling me the Boyer unit uses 1.5 v.
As before A is a red wire that goes from Boyer to far Right coil POS which terminal also runs to ground (siamese terminal). So if I understand you I need to bridge F the input) and A (the ground)?
I would have thought I was supposed to put the diode and capacitor in series like an inline fuse spliced into the F (white colored power feed to Boyer). My logic was to boost the intake to the Boyer during starting. But I am not an electrician like you.
Wish we had a way to input diagrams here. For the test my mini-battery NEG goes to the red ground wire "A" and the POS connects to F and also to main battery NEG?
Reading your description the diode/capacitor I am now confused. You did not mention a white Boyer wire before, that makes six wires, A, B, C/D, E (or F) and the white.
I thought the Boyer switched the coils on the ground side like the original analog unit and power from the ignition switch went to the negative side of the coils. From your description the B wire supplies power to the coils and the positive battery goes directly to the coil positive.
DO NOT BRIDGE THE F AND A WIRES.
Are you sure the black wire does not go to the positive side of the coils? And battery power connects through the ignition switch to the negative side of the coils?
Your proposed connections are wrong. First, write down each Boyer wire and where the instructions tell you to put them. I can draw a circuit diagram to show what I think is right.
Quote
Another possible solution is to use the Lucas battery eliminator capacitor with a diode before it in series and have that supply the Boyer electronics. The capacitor will keep supplying the Boyer as the voltage drops from the starter.

is this an experimental solution or something tested that works ?

not sure how ... , but if it works ... it works .

the boyer is wired normally ... plus some extras

the diode , goes in series ( right before the boyers white wire ) ..

the capacitor is not wired as shown on wiring diagram .
but
one capacitor lead goes to white wire (negitive if capacitor is polarized ) ( after the diode and before the Boyer box )
The other capacitor lead goes to ground ... anywhere that is convenient

The diode is going to drop 0.75 volts on the boyer input ( not an optimal situation where low voltage is already a problem )
but will act as a one way gate for the capacitors discharge .
and the capacitor will try and stabilize the voltage when the starter starts hogging the battery amperage .
( the capacitor isolated by the diode can only discharge into the boyer )
...and only needs to work until the bike fires .

is this the plan ?
Originally Posted by Randy M
Thanks, my alphabet was wrong, was tired, there's only 5 wires to/from the Boyer, so I meant E not F but to avoid confusion let's keep calling it F (the white and blue wire or white & yellow wire that runs from Batt NEG thru ign sw thru kill sw to the ballast resister (removed when using a Boyer) to connect with the white Boyer wire ) must be input power to Boyer,(last test shows 13.9 v when starter is not engaged).
I assume B (black) is the Boyer output as it goes to far Left coil NEG terminal. Last test showed it has 12.4 v at that terminal when ign on and no starter,

Originally Posted by DMadigan
Reading your description the diode/capacitor I am now confused.

To avoid further confusion I suggest using the wiring diagram colour codes.

http://www.boyerbransden.com/pdf/KIT00054__BOX00021_.pdf

[Linked Image from i.postimg.cc]
Thanks so much for the diagram. Dunno where U got it and how you managed to insert it but my system is exactly like that (plus it has a kill switch to the left to the ign sw.) .
So I insert the diode somewhere in the white wire left of the kill switch but before the Capacitor (reading from battery to Boyer transistor box). The diode has which end (+ or - ) closest to battery and which end closet to the Boyer?
Then I solder in the capacitor as close as possible to the Boyer. I solder the NEG end into the white wire so it ends up a T connection, and for the other Capacitor end (POS) I link to the + terminal of the # 1 coil for convenience, or any ground.?
So much thanks to Dave, Quinten and L.A.B.
Thanks LAB
I’d not imagined that the Boyer stator for the triples had that asymmetry to it. Not thought about it before.
I assume the rotor has 3 poles so 2 are triggering at any time.
Presumably wasted sparks every 240deg of crank.
It makes sense as only 2 output wires are required for the trigger box.

Of course it makes a difference in Boyer diagnostics between twins and triples, where with twins the resistance between B/W – B/Y should be something like 130ohm (each coil is usually ~66ohm), whereas the triple stator should measure about 48ohm (because of that 180ohm bridging resistor) between those leads. I didn’t know about that till now. And strangely the coils are noted as 33ohms in that diagram, that makes no sense to me, why wouldn’t the same coils be in use, as with other Boyer systems?

As for the diode and capacitor, I'll leave that to others.
Originally Posted by koan58
I’d not imagined that the Boyer stator for the triples had that asymmetry to it. Not thought about it before.

Early Boyer triples stators had three coils, however, according to John Healy"...the coil adjacent to the alternator would pick-up RF and confuse the triggering circuit...".

http://www.britbike.com/forums/ubbthreads.php/topics/766940/re-t160-electric-start#Post766940
If that diagram of the Boyer wiring is what you have then the diode/capacitor idea will not work. I thought the Boyer timing was powered separately and it switched the coils from the ground side.. Since the Boyer is switching the coils from the powered (B-) side the timing electronics shares the coil power lead.
The capacitor will not store enough energy to drive the coils when the starter draws down the battery voltage.
Dave Cameau tested the Boyer and found it went haywire at about 10 volts.
Originally Posted by DMadigan
Dave Cameau [Comeau] tested the Boyer and found it went haywire at about 10 volts.

That was the old Boyer Micro MkIII which this bike apparently had but no mention of starting problems until it was replaced with a MkIV which isn't as voltage sensitive.

http://www.boyerbransden.com/micromarkiv.html

"The Boyer Bransden range of Analogue MKIII ignition units are being progressively changed to improved MKIV versions*. The changes are designed to improve the timing stability if engine starting with a very low or variable battery voltage. The design changes are internal and do not affect the external appearance of the unit."

*(Old information as the Boyer MkIV has been around for several years now).
Wow all this electrical tech talk is getting beyond me, all i can say is that yes it is a wasted spark system, and I have the Mk IV transistor box (but did not change the Mk III pickups where the CB points used to be)
Hi Randy,

Late to the party here but I'm staggered that, more than twenty years after T160 electric-starting problems with Boyer-Bransden e.i. were thrashed out and solved on Triples On Line, there are still long threads about the problem. confused

Thick cables
Between battery -ve, solenoid and starter and between engine and battery +ve - I don't see any mention of these in your thread? It's well-known standard were under-spec'd; they should've been checked - and replaced if necessary - long before you "hammered", "stood on" or "claw hammer"-ed the starter (Jeez! shocked ).

If your bike's cables are ~5/16" o.d., chances are they're either original or poor copies:-

. Here in GB, I can buy cable known as "196/0.40" - 196 strands, each 0.4 mm. o.d., 25 sq.mm. total conductor cross-section, rated for 170 Amps. These are not "high purity" (wth is that? cool ), just bigger (~3/8" o.d.) and better-quality than originals.

. If you can't find something more similar, Dave Comeau (Norton Board moderator) has posted in the past he uses 6AWG cable on electric-start Commandos (which have a higher starting Amps than a T160).

Originally Posted by DMadigan
jumper cables are a cheap source for starter wires.
Expensive thick ones that'll jump diesels, thumbsup cheap thin ones that'll only jump gas engines, thumbsdown

Btw here, to amplify another of Dave's earlier answers, afaict T160 starters don't draw much more that the ones he sells - highest draw I can remember seeing from a Lucas starter was ~160 Amps.

Boyer-Bransden Transistor Box and ignition coils wiring
Once you're sure your bike has decent electric-starting cables (not forgetting the short one between solenoid and starter), ime don't wire the 'ground' (+ve) side of the Boyer-Bransden Transistor Box or coils series exactly like the diagram @L.A.B. posted:-

. connect the Box Red wire directly to the battery +ve terminal;

. either connect "Ignition Coil 1" +ve also directly to the battery +ve terminal or at least into the bike's existing harness Red wires' network, at a snap connector.

Btw1 here, you might want to consider a lower-rated fuse (5A or 7.5A blade) in the Transistor Box -ve, say where the Box White wire connects to the harness White/Yellow from the handlebar kill switch? Otherwise, the only 'protection' laughing the e.i. has is the 15A or 20A main fuse. frown

Btw2 here, the link @L.A.B. posted:-
... is corrupt:-

. if you look at B-B's Fitting Instructions index webpage, Code "KIT00054 (BOX00021)" equates to Description "Micro MKIV/MKIII ignition for Triumph Trident T150 / 160 and BSA Rocket Three Motorcycles.";

. however, if you click on the link @L.A.B. posted, the displayed fitting instructions are for B-B's MicroDigital e.i. (Code "KIT00085 (BOX00036)" in the index);

. the negative-side wiring is the same but KIT00054 (BOX00021) fitting instructions include an additional colour wiring diagram showing the positive-side wires connected into the bike's existing harness Red wires, similar to my advice.

Originally Posted by Randy M
I notice voltage drops to 10 when pushing the starter button.
Where are you measuring this? With your meter leads connected one to each battery terminal? Or one meter lead connected to battery +ve and the other lead connected to the connection between Box White and harness White/Yellow? Risking telling you something you know already, you should make both measurements with ignition and kill switches turned on, to ensure there isn't Volts drop between battery -ve and the Box White wire.

Ignition coils
Another thing I don't see in the thread is checking the coils? confused If you haven't done it before, set your meter to Ohms:-

. Primary resistance is each meter lead end on one of the spade terminals secured by a nut; 'original Lucas' (as fitted to your bike when new) were/are usually ~1.8 Ohms, common replacement PVL can be up to 2.2 Ohms; the ones you do not want are the current Wassell Lucas with 5-Ohm shocked primary resistance.

. Also check resistance between each coil's HT terminal and its LT (spade) terminals - should be about 5,000 Ohms but old PVL can be up to 7,000 Ohms.

. Finally, check between each terminal and the coil casing, should be tens of thousands of Ohms.

Having ensured decent electric-starter cables and decent ignition wiring both -ve and +ve and 'good' coils, the '6V' might now work with electric-starting for you - they have for many T160 owners over the years.

If they don't, consider '4V' coils; fwiw, a number of T160 owners have posted over the years both here and on TOL that '4V' coils with B-B has worked for them. Otoh, I can't remember a post by anyone actually using "capacitor-'n'-diode"? confused

Fwiw, never been impressed with three '6V' coils in series on a triple, but then I've always been a Lucas Rita (three '4V' coils as standard) user. wink The reasons Bransden has always used '6V' coils were two-fold originally:-

. When the only competition to B-B was Rita, Lucas supplied three '4V' coils for triples but, as they made the coils, Lucas were hardly going to supply their main competitor ...

. While Bransden had to supply replacements for T150 and Rocket 3 '12V' coils, '6V' coils - even Lucas - were always easily-available; however, T160's came with '6V' coils as standard, so Bransden could make his e.i. look cheaper than Rita.

However, Rita hasn't been available new for decades, but '4V' coils are now easy; given the well-known problems with three '6V', Gk why Bransden continues to recommend 'em. confused

Originally Posted by Randy M
insert the diode
As I say, never known anyone actually do this ...

Firstly, the capacitor is across the battery; i.e.:-

. Capacitor -ve must be connected in a wire connected to battery -ve - I suggest around the connection between the Transistor Box White wire and the harness White/Yellow?

. Capacitor +ve must be connected in a wire connected to battery +ve - I suggest an existing Red wires' snap connector. But not "any ground" - "ground" is simply an electrical conductor between battery +ve and another component; like the Transistor Box and coils +ve connections I've advised above, make it a good one (not some crappy connection to some random bit of bike).

Originally Posted by Randy M
Then I solder
Imho, no. Use bullets into snap connectors - if this idea turns out to be crap, you don't want messy soldering to clean up particularly in the supply to the Transistor Box -ve; bullet 'n' snap connectors, you just pull the cap's bullets out of the relevant snap connectors.

Originally Posted by Randy M
capacitor as close as possible to the Boyer.
Afaict, the obvious connection seems to be around the existing connection between Transistor Box White wire and harness White/Yelllow? However, I've also advised a fuse for the B-B and the diode has to be connected somewhere?

Originally Posted by Randy M
diode has which end (+ or - ) closest to battery
Educated guess says the diode should be between battery -ve and capacitor -ve, to prevent the capacitor's discharge towards the battery.

If so, that's on the end of the harness White/Yellow wire, between it and the capacitor, and the White/Yellow is connected (through the kill and ignition switches) to battery -ve ...? wink

Hth.

Regards,
Also for a Boyer (at least the analog versions), one is told to remove the ballast resistor (mine has been removed), and keep the stock 6 volt coils, (Walridge Motors recommends 4 v coils for better performance due to less resistance) .
Originally Posted by Stuart
Late to the party here but I'm staggered that, more than twenty years after T160 electric-starting problems with Boyer-Bransden e.i. were thrashed out and solved on Triples On Line, there are still long threads about the problem.

However, as I understood it from Randy M's original post that the non-starting on the electric starter problem began after the MkIII box had been replaced with the MkIV box.



Originally Posted by Stuart
Btw2 here, the link @L.A.B. posted:-
... is corrupt:-

however, if you click on the link @L.A.B. posted, the displayed fitting instructions are for B-B's MicroDigital e.i. (Code "KIT00085 (BOX00036)" in the index);

the negative-side wiring is the same but KIT00054 (BOX00021) fitting instructions include an additional colour wiring diagram showing the positive-side wires connected into the bike's existing harness Red wires, similar to my advice.




The actual Kit00085 instruction sheet has the colour diagram. 00054 and 00085 both have a diagram showing the harness red connection (also mentioned in both sets of instructions) only 00054 (below) is not colour.

[Linked Image from i.postimg.cc]


Correct Micro MkIII (also MkIV) instruction sheet from another source (the circuit diagram is the same).
http://www.britcycle.com/Manuals/33103inst.pdf
Hi Randy,

Originally Posted by Randy M
Also for a Boyer (at least the analog versions), one is told to remove the ballast resistor
Same for all e.i.

The ballast resistor has a similar resistance (~1.8 Ohms) to an 'original Lucas' '6V' coil primary. When the coils are switched by points, operating normally, the T160 coils are supplied through the b.r. This connects the b.r. 'in series' with each coil; when individual electrical components are connected 'in series'. their individual resistances are added together - b.r. ~1.8 Ohms and a '6V' coil ~1.8 Ohms roughly equals the ~3.5 Ohms of a '12V' coil's primary resistance, and the rest of a T160's electrics are 12V. grin

Reason Lucas and Triumph did it this way is, when the starter button's pressed, it operates the relay (under the battery carrier as standard); as well as powering the starter solenoid, the relay has a wire (from terminal "C4") to the 'coils side' of the ballast resistor; i.e. that wire bypasses the b.r. Reason for that is, Lucas knew operating the starter could drop the battery/DC system Volts below 12V, if '12V' coils were used, the <12V might prevent them generating an HT spark = bike not starting = annoyed owner. Otoh, '6V' coils getting 6+V, they'd be more likely to generate an HT spark = engine starts, happy owner releases the starter button, relay and ballast resistor bypass off, '6V' coils back to "operating normally".

Wasn't a new system, Lucas had supplied similar as far back as the late 1950's afaik and, before that, it had been used on cars with early electric starters.

However, if an e.i. intended to work with 12V only has 6V, it won't work. So all e.i. fitting instructions say to disconnect the kill switch White/Yellow from the ballast resistor and connect it directly to the e.i. input (B-B Transistor Box White wire on your bike). The Box also switches the coils on and off - respectively to charge them and generate an HT spark - so the ballast resistor becomes redundant.

Originally Posted by Randy M
Walridge Motors recommends 4 v coils for better performance due to less resistance
wink

Btw, a check for your bike - does it have one or two harness Red wires attached to battery +ve? If it does, you should disconnect them and tape up the terminal securely. Reason is, they're a fire hazard. frown

Problem is, the Red wires are also connected to the engine (usually at one of the head studs or bolts through a rocker-box). Because the starter 'grounds' through its mounting on the engine, if you ever forget to connect the thick cable either to the battery +ve terminal or wherever the other end's attached to the engine, and then you operate the starter, it'll try to complete its circuit back to battery +ve through the thin Red wires between rocker-box and battery +ve sick ... with spectacular (one-off) results ...

Otoh, if you disconnect the Red wires from battery +ve, the thick cable on battery +ve is the only 'ground' for all the electrics; if you forget to connect either end, you'll know as soon as you switch on but no harm done. thumbsup

Hth.

Regards,
Originally Posted by Randy M
Also for a Boyer (at least the analog versions), one is told to remove the ballast resistor (mine has been removed), and keep the stock 6 volt coils, (Walridge Motors recommends 4 v coils for better performance due to less resistance) .


In your first post you said that after attempting to remove the starter motor by "hammering" at it (and using a screwdriver as a chisel) the starter motor no longer worked as the solenoid only clicked, so is the starter motor working now?
See Sept 30 re starter removal. The shop manual only mentions the 3 "screws" Dave Madigan told me where to find the one behind the solenoid, after removing that it came off with zero resistance. The starter has always worked fine. BTW I (and previous owner) already done all of Stuart's recommendations except replacing the wee cable between solenoid and starter because when I doubled it with a 16 gauge wire to see if there was high resistance there it had no effect on the 2 v drop issue. (Main cable was replaced by me with thicker one.) I checked the coils many X to ensure were wired the way the diagrams supplied by you folks specified and they were correct, and I measure the resistance at 1.6 ohms each so the coils are not a problem.
Originally Posted by Randy M
See Sept 30 re starter removal. The shop manual only mentions the 3 "screws" Dave Madigan told me where to find the one behind the solenoid, after removing that it came off with zero resistance. The starter has always worked fine.


Yes, but in your first message you said...
"Big test: Oh, oh, the starter only clicks at the solenoid. (battery still 12 v) Plus, when i kick over the bike there is a strange clicking sound. I removed the plunger and it made it worse, felt resistance while kicking and more noise."
...at which point the starter apparently wasn't working fine so can you confirm the solenoid and starter motor operate normally when you press the starter button but the engine just doesn't start.

Some voltage drop is to be expected when the starter motor operates but if it was starting ok beforehand with the Boyer MkIII box then the MkIV box is supposed to operate at a lower voltage than the MkIII box.
Sorry LAB, you are right, that was a temp problem due to my buggering things up trying to remove the starter/solenoid. I removed the plunger thinking maybe it was holding things in, once i got the s/s off I put the plunger back in its proper position and that solved the weird noise problem. Starter and solenoid work perfectly now..
1 BRIEF STEP AHEAD, 2 STEPS BACK
Fixed the starter voltage drop issue via the diode and capacitor (but only briefly) but now I have no more spark! (and the draw is creeping back to 2 v)

Before Installing the diode and cap. I tried to do a test by inserting a small 12v battery from a dirt bike where the cap would go. I grounded the POS to the main battery but the instant I touched the NEG to the connection that connects the dual colored ign wires to the white Boyer wire the dash lights lit up even though the ign was not turned on. I realized this is bec. I had no diode to prevent backward current. I only tried this 3X for an instant . Would this have ruined the Boyer box? Apparently not, see last para.
I did not check for spark then, did not occur to me to see if I still had spark.
So I installed the diode and Cap as per Quinten’s instructions : Diode with NEG from the dual colored original feed wires and POS facing twd the Boyer and then I connected the Cap to the diode with the NEG connected to the diode POS end, and also connected the white Boyer wire there (a T connection into the Cap NEG end wire). The POS end of the cap I presumably grounded but cannot remember doing so and suspect I forgot.
When I then used the e-starter instead of a 2 v drop across the battery I only got 1 v drop so Hooray and I soldered in the connections taking care not to apply heat for more than a few secs at a time and using very thin fast melting solder and using a vice grips as a heat sink. Also for the end of the diode that connects to the stock dual colored ign wire I crimped rather than soldered. I attached the cap. POS ground to the engine (maybe that will got too hot if the engine ever runs, I shld ground it to a cooler spot.) I tried the starter and again only a 1 v drop.
Hooray again until I noticed that my test spark plug taped to the head was no longer sparking. ! step ahead and 1 big step back.
So I cut all the soldered connections and removed the diode and Cap and reconnected to the “status quo ante” and now have my spark again so did not ruin the Boyer.
I then discharged the Cap and tested it and it still says 5000uF so I used a new diode and the same Cap. (properly grounded) with good but not soldered connections and but still no spark; also its now back to taking 1.7 v instead of 1 at the starter.
But I think Dave Madigan answered all this on Oct. 10 when he wrote:
If that diagram of the Boyer wiring is what you have then the diode/capacitor idea will not work. I thought the Boyer timing was powered separately and it switched the coils from the ground side.. Since the Boyer is switching the coils from the powered (B-) side the timing electronics shares the coil power lead.
The capacitor will not store enough energy to drive the coils when the starter draws down the battery voltage.

So it was fun experimenting (the Cap and diodes only cost me $23) and learning more about electronics but seems I am going to have to do like everyone else and spend a small fortune for a Tri-Spark kit when I may be able to afford it.
BUT the big mystery is that two companies that sell e-ignition kits (not just Boyers) say that they have many happy T160 customers using analog Boyers, and my own bike started and ran from 2012 thru 2018 on the old Boyer Mk III until it gradually failed in 2019. One would assume putting in the new Mk IV would have at least put me back to where I was a few years ago, esp. since then I have replaced a few dodgy wires, installed fatter starter cable, cleaned connections, cleaned the starter, new Odyssey US made battery, new spark plugs and ensured the HT leads are compatible with the Boyer, checked coil resistance, new solenoid about 2 years ago, and made sure to my bile follow John Healy’s advice (it already did) that “Alternator wires should never be located near, or run parallel to, the timing plate wires, or battery ground or feed wires. For example: T160 wiring harness carries the alternator wires in the same wiring sub-harness with the wires coming from the timing plate. etc. Well at least I reduced the draw from 2.0 to 1.7 volts.

The only thing I can think of is maybe previous owner had the coils wired differently than the way shown in the diagrams above as I recall switching a couple of wires last year to make them jibe with the Boyer diagrams. Be funny if by wrongly linking the coils he was able to make it run.
PS I ordered one of the original blue capacitors (common on most Brit bikes, optional on T160). Just wondering if installing this either with the current failed mods or w/o them will have any effect? Also wondering if they had a built in diode as otherwise what to prevent current going the wrong way?
I cannot tell from your description if you wired the diode and capacitor correctly. A diode has an anode and cathode. The capacitor should go between the Boyer white and red wires. No idea why you are checking the voltage across the battery, it is the voltage across the Boyer that is significant.
Is this how you wired the diode and capacitor?
[Linked Image from i.postimg.cc]
Do you have a capacitance meter? How did you check it?
The problem with using the diode and capacitor on this Boyer is the timing circuit power and coil switching power are not separate. Try putting a volt meter across the capacitor terminals then connect a battery across the capacitor terminals to charge it. Remove the battery and the voltage across the capacitor will very slowly drop. Recharge the capacitor with the battery then after the battery is disconnected connect the terminals of a coil across the capacitor. The voltage will drop to zero faster than your meter can react.
Originally Posted by Randy M
Before Installing the diode and cap. I tried to do a test by inserting a small 12v battery from a dirt bike where the cap would go. I grounded the POS to the main battery but the instant I touched the NEG to the connection that connects the dual colored ign wires to the white Boyer wire the dash lights lit up even though the ign was not turned on. I realized this is bec. I had no diode to prevent backward current. I only tried this 3X for an instant . Would this have ruined the Boyer box? Apparently not, see last para.
I did not check for spark then, did not occur to me to see if I still had spark......

What do you mean by "...dual colored ign wires..."? The only wire connection to Boyer box white should be the kill switch white/yellow.

Originally Posted by Randy M
BUT the big mystery is that two companies that sell e-ignition kits (not just Boyers) say that they have many happy T160 customers using analog Boyers, and my own bike started and ran from 2012 thru 2018 on the old Boyer Mk III until it gradually failed in 2019. One would assume putting in the new Mk IV would have at least put me back to where I was a few years ago

Precisely, so if it started ok for six years with the MkIII box then it should do the same (or better) with the MkIV without the need for a diode or capacitor.
I am unable to open D Madigan's image. Can someone tell me how I can attach a diagram to this forum so I can show how I hooked up the Diode and Cap? Maybe be moot now as now even after removing them I have no spark at all (even when kicking) and even when I connect the Boyer white wire directly to the battery Neg.
(I know its a good connection because tiny spark when I connect). So I must have blown the Boyer?
PS to L.A.B - By dual colored I meant the white and blue (maybe one is white and yellow) one of which for sure carries power from the kill switch and presumably the other used to go to or from the ballast resister (removed from my system). They are joined together where they connect to the Boyer white. THANKS AGAIN TO ALL WHO ARE OFFERING HELP.
Quote
PS to L.A.B - By dual colored I meant the white and blue (maybe one is white and yellow) one of which for sure carries power from the kill switch and presumably the other used to go to or from the ballast resister (removed from my system). They are joined together where they connect to the Boyer white

its not clear from your post , it sounds like you may have more than one wire
connected to the boyer White ?

i would use... only the one ... white/yellow wire from the kill ( with ballast bypassed/removed )
... not a wire from the solenoid relay , to power the boyer box .
(white/blue wire removed from bike )

at the risk of stating the obvious ,
a white wire in britbike parlance , just means... ignition key switched power ...
but often on it way to "more than one" secondary switch connection .
later britbikes with
"more sophisticated wiring" , will have the key-switched wire color-change
downstream of the kill-switch- cluster .

boyer cant know all the kill wire colors used over the years for different models/brands , so they stuck with
... a general lucas color for key switched power ... white

[Linked Image from triplesonline.com]
using advanced reply
copy/paste
http://triplesonline.com/images/factory/75T160_wiring.png
into the [ drop down image box ]
then use preview to preview .
Originally Posted by Randy M
PS to L.A.B - By dual colored I meant the white and blue (maybe one is white and yellow) one of which for sure carries power from the kill switch and presumably the other used to go to or from the ballast resister (removed from my system). They are joined together where they connect to the Boyer white.

Look at the Boyer circuit diagram I posted previously. White/yellow should be definite not "maybe". There's no white/blue on that diagram. Edit: The only wires connected to the coils should be as shown on the Boyer diagram.

However, with white/blue (WU) also connected to Boyer white then it must only be connected to the relay C4 terminal. If, for instance, WU was also connected to the coils then that would result in the electronic ignition not sparking during starter motor operation. Edit: I reiterate that 'diodes' and 'capacitors' shouldn't be necessary.


Originally Posted by quinten
i would use... only the one ... white/yellow wire from the kill ( with ballast bypassed/removed )
... not a wire from the solenoid , to power the boyer box .
(white/blue wire removed from bike ).

Boyer cant know all the kill wire colors used over the years for different models/brands , so they stuck with
... a general Lucas color for key switched power ... white

Under normal circumstances (for standard points ignition) the white/blue ballast bypass wire connects to the relay (C4 terminal), not the "solenoid".


Agreed, that white/yellow (from the kill switch) should connect to Boyer white and that would be correct for the T160.

The wire from the ballast resistor to the coils shown on the T160 circuit diagram can be white/yellow (WY) and not white/blue (WU). Edit: However, regardless of the actual colour code it must be disconnected from the coils.
Originally Posted by Randy M
I am unable to open D Madigan's image.

=

[Linked Image from i.postimg.cc]
Thanks to all for their patience with my mediocre knowledge of electronics.. .
On my bike there is a White and Blue wire (original looking) wire from the ign and kill switch towards the battery/seat area. At that end (where I connect it to the Boyer white wire) it has another White and Blue wire sprouting off from the connector clip for about 6” to nowhere. Originally that short wire connected to a ballast resister and then a Blue and Yellow wire ran to terminal C-4 of the Relay. The resister and the Blue & Yellow wire were removed by previous owner. Hence there is nothing going to C-4.
BTW my battery is sitting at 14v but the power from the end of the White and Blue wire is only 13.75. Should I worry about the loss of 0.25v thru the system?
Originally Posted by Randy M
On my bike there is a White and Blue wire (original looking) wire from the ign and kill switch towards the battery/seat area.

There's no white/blue "from the ignition and kill switch" (see T160 diagram).

The ignition switch to kill switch wire is white (W) then white/yellow (WY) from the kill switch to the (now removed) ballast resistor (see T160 diagram).

Only the white/yellow from the kill switch should therefore be connected to the Boyer box white wire (see Boyer diagram).


Originally Posted by Randy M
At that end (where I connect it to the Boyer white wire) it has another White and Blue wire sprouting off from the connector clip for about 6” to nowhere. Originally that short wire connected to a ballast resister and then a Blue and Yellow wire ran to terminal C-4 of the Relay.

The C4 wire should be white/blue (WU).


Originally Posted by Randy M
The resister and the Blue & Yellow wire were removed by previous owner. Hence there is nothing going to C-4.

As mentioned, the C4 wire is normally white/blue (WU).

Blue/yellow (UY if fitted) is an automatic lights on control (item 19, T160 diagram) wire, not an ignition wire.



Originally Posted by Randy M
BTW my battery is sitting at 14v but the power from the end of the White and Blue wire is only 13.75. Should I worry about the loss of 0.25v thru the system?

There shouldn't be any power in the white/blue as it should've been disconnected.

As already mentioned the Boyer box should be powered by white/yellow from the kill switch.
Thanks again L.A.B. Seems previous owner or the last mechanic to work on it must have changed the wires so the colors are mixed up but its the same feed wire (connected to the Boyer white wire) the bike was running on since 2012 and it has about 14v, zero when the kill switch is activated so that proves it comes from the kill sw., and it sparks the plugs when kicked, Few weeks ago the bike did start and run fine this way (after kicking, would not e-start), the ride was only aborted when throttle cable broke.
The only white or white and yellow wires go to the rectifier and turn signal flasher.
Here is the latest: still no spark when starter engaged – actually with all 3 plugs unscrewed from the head and sitting on it as a ground, each plug sparks once as soon as I hit the starter button and once the instant I lift my finger off but not in between (tried as long as 8 seconds). Voltage drops from 14 to 12.25v across the battery during this time (no compression), and when measured from the white wire to ground from 13.75 to 12 v. One would think that with 12V and no compression the plugs would fire. I wiggled the White and Blue wire and the two pickup wires near their connections but it had no effect. According to Walridge Motors there shld be 1.5 ohms across the two pickup wires near the Boyer so I will measure this tomorrow. Is it possible the problem is with the old magnetic rotor or pickups rather than the (new) transistor box?
Originally Posted by Randy M
Thanks again L.A.B. Seems previous owner or the last mechanic to work on it must have changed the wires so the colors are mixed up but its the same feed wire (connected to the Boyer white wire) the bike was running on since 2012 and it has about 14v, zero when the kill switch is activated so that proves it comes from the kill sw., and it sparks the plugs when kicked,

Ok.


Originally Posted by Randy M
Few weeks ago the bike did start and run fine this way (after kicking, would not e-start), the ride was only aborted when throttle cable broke.

Was that after the Boyer MkIV had been fitted?



Originally Posted by Randy M
The only white or white and yellow wires go to the rectifier and turn signal flasher.

There would normally be a white to the flasher relay but no white or white/yellow to the rectifier so more odd wiring.



Originally Posted by Randy M
Here is the latest: still no spark when starter engaged – actually with all 3 plugs unscrewed from the head and sitting on it as a ground, each plug sparks once as soon as I hit the starter button and once the instant I lift my finger off but not in between (tried as long as 8 seconds). Voltage drops from 14 to 12.25v across the battery during this time (no compression), and when measured from the white wire to ground from 13.75 to 12 v. One would think that with 12V and no compression the plugs would fire.


Yes, as I'd have thought a Boyer MkIV would continue to function normally below 12.25V.


Originally Posted by Randy M
According to Walridge Motors there shld be 1.5 ohms across the two pickup wires near the Boyer so I will measure this tomorrow. Is it possible the problem is with the old magnetic rotor or pickups rather than the (new) transistor box?



I think the pickup is the same for MkIII and MkIV. If it was a pickup problem then I would expect it to affect kickstarting as well, however, it's something to check.
Originally Posted by Randy M
According to Walridge Motors there shld be 1.5 ohms across the two pickup wires near the Boyer so I will measure this tomorrow. Is it possible the problem is with the old magnetic rotor or pickups rather than the (new) transistor box?

if it kick starts , its not the stator-pickups or rotor-magnets
and
Assuming the ohms numbers on this diagram are correct , the 2 stator coils are in series ... with a resistor in parallel
[Linked Image from i.postimg.cc]
the resistance at the stator lead-wires would be
48.3 ohms

many/some report that a boyer iv can be used with E-start ... if the wiring is good to excellent ...
... so , i think this is more a matter of chasing wiring integrity .
made more complicated by the last owner going cowboy with the harness colors and connections .
( makes me wonder where other wiring suprises may lie unseen )

the kill switch should now only run the boyer-box and through the boyer , the ignition coils .
(but the coils are normally off and are only momentarily energized for firing ... the coils may
also fire once when box is first energized or when turned off )

the start button should now only run a simpler relay funtion ... which activates the starter-solenoid .
Currently I still have the issue of no spark when using the e-starter (except at the instant I hit the starter and the instant I release it, nothing in between and I’ve tried for as long as 8 seconds) HOWEVER per a suggestion from Mark who runs British Cycle Supply in Maine and Nova Scotia , if I jump a 16 gauge wire from Battery Neg to the Boyer white wire (bypassing all the usual wires and connections and the ign and kill switch) I DO get spark during e-cranking. Likewise when I hook up a separate battery I also DO get spark at all times. (Mike Partridge wrote saying he once had a T160 and the extra battery he carried, with a switch, was the only way he could start it with the e-starter.)
Thinking possible degradation in the wiring and worrying about what Stuart was worrying about (wrong colored wire feed the Boyer) I found the White and Yellow wire in the kill switch and traced it back but it disappears aft of the battery and never reappears! I checked physical condition and continuity if it up to near the battery (it was fine) so snipped it off there and soldered on a connector so I can connect it to the Boyer. Snipping the WY wire had no effect of the Low tension system so that shows it really was not hooked up to anything. As for improving my HT problem the result was also zero effect. (As for the Blue and White wires that I formerly used I taped them off.)

Again voltage at the terminus of the WY wire is just under 14 v not connected to the Boyer and when I crank the e-starter it drops 2 volts. However no spark. When I connect the WY to the Boyer it is still just under 14 v but hitting the starter button the voltage drops to 3 volts. So:
Q1: why with Boyer hooked up does voltage drop change from about 2 to a whopping 11?.
Q 2: a) Since the WY wire from the kill switch shows 13.75 v with ign on (but no starter) why is it that by temp unhooking the Boyer and connecting it to the Battery or a remote battery giving it 14v it should make no difference, or is it the extra amps that makes the difference. b) Is it possible that the wiring is reducing amperes not volts?
Q 3: As a solution until such a time as I may be able to afford a Tri-Spark kit, can I run a new permanent wire from Batt neg to the Boyer/WY connection (so there are 3 wires connected) but have a toggle switch in the new wire between the Batt and the 3 way connection for starting only? Not sure where I would locate it so its out of the rain but accessible but not too conspicuous.
Originally Posted by Randy M
HOWEVER per a suggestion from Mark who runs British Cycle Supply in Maine and Nova Scotia , if I jump a 16 gauge wire from Battery Neg to the Boyer white wire (bypassing all the usual wires and connections and the ign and kill switch) I DO get spark during e-cranking.

Connect the jumper wire between the relay C4 terminal and Boyer white and see if you get the same result?
Originally Posted by L.A.B.
Originally Posted by Randy M
HOWEVER per a suggestion from Mark who runs British Cycle Supply in Maine and Nova Scotia , if I jump a 16 gauge wire from Battery Neg to the Boyer white wire (bypassing all the usual wires and connections and the ign and kill switch) I DO get spark during e-cranking.

Connect the jumper wire between the relay C4 terminal and Boyer white and see if you get the same result?

its worth a try , and a good idea ( except )
relay terminal at C1 is an unfused battery connection .
when the starter relay is energized ... C2 an C4 are contacted and have
a fairly Direct battery connect .
... if it solves the problem ... fuse between C4 and Boyer box white
Originally Posted by quinten
its worth a try , and a good idea ( except )
relay terminal at C1 is an unfused battery connection .
when the starter relay is energized ... C2 an C4 are contacted and have
a fairly Direct battery connect .

Just as it would be if C4 was used as the ballast bypass wire for the original points ignition.

C4 only being live/hot whilst the starter motor operates and was suggested as a test which might not work judging by the odd wiring on this bike.


Originally Posted by quinten
... if it solves the problem ... fuse between C4 and Boyer box white

If it works then it could be made permanent and a fuse included but the C4 wire would only be bypassing the circuit problem wherever it might be.
Hi Randy,

Originally Posted by Randy M
BTW my battery is sitting at 14v but the power from the end of the White and Blue wire is only 13.75. Should I worry about the loss of 0.25v thru the system?
No.

Originally Posted by Randy M
Voltage drops from 14 to 12.25v across the battery during this time (no compression), and when measured from the white wire to ground from 13.75 to 12 v.
Mmmm ... I'm curious about this battery that's "sitting at 14v", what sort is it - ordinary lead-acid, AGM, gel, lithium-iron? What make? What Amp-hour rating?

Originally Posted by Randy M
until such a time as I may be able to afford a Tri-Spark kit, can I run a new permanent wire from Batt neg to the Boyer/WY connection
I hate to rain on your parade but, absent a problem with the existing Boyer-Bransden e.i., a Tri-Spark is not going to fix the particular wiring and/or other electrical problems your bike has:-

. To my certain knowledge, electric-starting a T160 fitted with Boyer-Bransden e.i. has not been a widespread general problem for twenty years.

. Therefore the problem you're experiencing must be down to one or more things on your bike - e.g. if "a new permanent wire from Batt neg to the Boyer/WY connection" 'fixes' the problem, the problem(s) lie(s) between battery -ve and the harness connection to the B-B White wire; why not just find and fix it/them? You have a meter, all you have to do is measure the Volts between battery +ve and each connection; when the Volts aren't 14V or 13.75V, you've found the (first) problem; fix that and carry on checking; when your meter displays 14V (or 13.75V) between battery +ve and the connection between the harness and the B-B White wire, you've probably found the problems between battery -ve and the connection between the harness and the B-B White wire. If the B-B Red wire and the "+" terminal of the last coil in the array are both connected directly to battery +ve, that should be at least the ignition LT circuit sorted.

Btw, when testing connections in any circuit, all switches must be on and all connections must be complete, don't disconnect anything; if you break the circuit, any Volts readings are meaningless.

Hth.

Regards,
Are you measuring 13.75 volts on the white-blue wire without anything connected to it? Any voltage drop with no load is going to be more of a problem with a load. Between what points are you measuring, battery and white-blue, Boyer red and white-blue, coil+ and white-blue?
Boyer boxes normally switch off after a few seconds of inactivity. The Micro-MkIV is the same, presumably.

http://www.boyerbransden.com/faultfinding.html

"The Micro-MKIII, Micro-Digital and Micro-Power units all turn off when not being triggered,..."
Hi Les,

Originally Posted by L.A.B.
Boyer boxes normally switch off after a few seconds of inactivity. The Micro-MkIV is the same, presumably.

http://www.boyerbransden.com/faultfinding.html

"The Micro-MKIII, Micro-Digital and Micro-Power units all turn off when not being triggered,..."
Aiui from John Healy's past posts, specifically triple ones don't?

Hth.

Regards,
Results of test recommended by LAB and Stuart (thanks so much)
IT WORKED! When I jump a wire from C-4 of relay to the connection between the starter wire (was Blue & White, now using the Yellow & White, both have 13.75 v) and the white Boyer box input wire, I get consistent spark during e-start.
New mystery: After I remove the jumper wire and push the starter button I sometimes STILL get a consistent spark. BUT if I turn ign switch OFF and wait a minute or two and try again, that mystery spark has disappeared and I am back to the status quo ante (no spark during e-start). This happened 2 tests in a row but not the 3rd time, then it did happen the 4th time and after releasing the button and trying again not the 5th time. Then on the 6th try I simply pushed and held then released the starter button several times and the first 3 X I got spark (not after that). Almost as if the relay has its own condenser/capacitor. (I have NO capacitors on the bike right now, abandoned previous cap and diode experiment) Comments? (call this issue A)
SO I will install a permanent wire between C-4 and the junction between the dual colored wire and the B-B white with an inline fuse.
So now my Q (call this issue B) is should fuse be same amps as main fuse (UK 35, US 17.5 or 20) or is it better to use the 7.5 amp (US) fuse previously recommended to protect the B-B?
BTW, I am using the far right cylinder for spark testing and all this has revealed a partial answer to an old issue. After the testing and even when ign switched off about 1 to 2 seconds later I get a weak residual spark or two. Over the years (with the Mk III and this new Mk IV) I have noticed that after switch off I sometimes get a loud pop (sounds like a gun shot) from the right muffler. Was told residual unexploded mixture in there was igniting from excess heat in the Right cylinder/header/muffler. Now I know its from a late spark. Sometimes when doing the latest experiment when i switch on the ign before doing anything else there is a wee crackle and tiny spark from the R cyl. Comments? (call this issue C)
Originally Posted by Randy M
So now my Q (call this issue B) is should fuse be same amps as main fuse (UK 35, US 17.5 or 20) or is it better to use the 7.5 amp (US) fuse previously recommended to protect the B-B?

To answer 'B' first, a 7.5A continuous fuse should be adequate.



Originally Posted by Randy M
Results of test recommended by LAB and Stuart (thanks so much)
IT WORKED! When I jump a wire from C-4 of relay to the connection between the starter wire (was Blue & White, now using the Yellow & White, both have 13.75 v) and the white Boyer box input wire, I get consistent spark during e-start.
New mystery: After I remove the jumper wire and push the starter button I sometimes STILL get a consistent spark. BUT if I turn ign switch OFF and wait a minute or two and try again, that mystery spark has disappeared and I am back to the status quo ante (no spark during e-start). This happened 2 tests in a row but not the 3rd time, then it did happen the 4th time and after releasing the button and trying again not the 5th time. Then on the 6th try I simply pushed and held then released the starter button several times and the first 3 X I got spark (not after that). Almost as if the relay has its own condenser/capacitor. (I have NO capacitors on the bike right now, abandoned previous cap and diode experiment) Comments? (call this issue A)
SO I will install a permanent wire between C-4 and the junction between the dual colored wire and the B-B white with an inline fuse.

BTW, I am using the far right cylinder for spark testing and all this has revealed a partial answer to an old issue. After the testing and even when ign switched off about 1 to 2 seconds later I get a weak residual spark or two. Over the years (with the Mk III and this new Mk IV) I have noticed that after switch off I sometimes get a loud pop (sounds like a gun shot) from the right muffler. Was told residual unexploded mixture in there was igniting from excess heat in the Right cylinder/header/muffler. Now I know its from a late spark. Sometimes when doing the latest experiment when i switch on the ign before doing anything else there is a wee crackle and tiny spark from the R cyl. Comments? (call this issue C)

As the jumper wire from C4 to Boyer white worked and from your description it seems to point to a bad connection in the ignition circuit.

Possibly a corroded, burnt or worn ignition switch or kill switch contact or corroded pins and sockets of the RH switch cluster multi-pin plug (white and white/yellow wires) which are barely adequate electrical conductors when in good condition.

[Linked Image from i.postimg.cc]
[Linked Image from i.postimg.cc]


If you can find the fault and correct it then it shouldn't need a permanent C4 to Boyer white connection.
thanks so much but I did check the same connections as in your photos and they looked as new. Also I had the ign sw apart last summer (no use since then other than the aborted test ride) and the terminals all looked fine. I DO have 13.75 v where the Yellow& White (also Blue and White) wires come back to the seat area from the kill switch after going from batt to ZD to ign sw to kill switch.
Thanks to you after about 180 hours spent I now have spark during cranking (and kicking, and under compression) by following your and Stuart's advice. I installed a 7.5 amp fuse en route.   However weirdly after I disconnected the batt to solder in after mocking up, when i reconn the batt the dash lights lit up. (Current going in reverse?) Not knowing what to do I turned the ign ON and then OFF and that seemed to reset it and its normal again. I have now removed the batt for winter storage so expect the same weird result in Spring when I reconnect. Is this harmful?  Any thoughts on issues A and C?
Quote
I installed a 7.5 amp fuse en route

in route to what , from where ? between starter relay C4 and ? ... the boyer white
( with the wire from the kill-switch connected ... at the boyer white also ) .

C4 should only be hot when the start button activates the starter relay .
the fuse needs to protect against overloading the kill-switch ( in a couple of unexpected scenarios )
( there is a possibility for current to go both ways when the start button is pressed )
Originally Posted by Randy M
thanks so much but I did check the same connections as in your photos and they looked as new. Also I had the ign sw apart last summer (no use since then other than the aborted test ride) and the terminals all looked fine.

However, as you mentioned previously, operating the ignition switch seems to cause things to change so could be worth another look.



Originally Posted by Randy M
I DO have 13.75 v where the Yellow& White (also Blue and White) wires come back to the seat area from the kill switch after going from batt to ZD to ign sw to kill switch.

If, as you said previously, white/yellow is powering the Boyer as it had been white/blue (there are white/blue WU and blue/white UW wires on a T160) then white/blue shouldn't have voltage so needs investigating where it's getting its power from.


Originally Posted by Randy M
Thanks to you after about 180 hours spent I now have spark during cranking (and kicking, and under compression) by following your and Stuart's advice. I installed a 7.5 amp fuse en route.   However weirdly after I disconnected the batt to solder in after mocking up, when i reconn the batt the dash lights lit up. (Current going in reverse?) Not knowing what to do I turned the ign ON and then OFF and that seemed to reset it and its normal again.

It seems unlikely that power going to the dash lights would have come from the C4 terminal without the starter button being pressed, and once again, operating the ignition switch appeared to cure an apparent problem.


Originally Posted by Randy M
Any thoughts on issues A and C?

I thought 'A' was what we had been discussing.


Originally Posted by quinten
C4 should only be hot when the start button activates the starter relay .
the fuse needs to protect against overloading the kill-switch ( in a couple of unexpected scenarios )
( there is a possibility for current to go both ways when the start button is pressed )

If there's no power in the electrical system then the relay wouldn't operate but if power was lost during the relay operation then I expect that could happen.
A diode (oh no, back to diodes again) connected to WY I think would prevent that.
Q to LAB: I have the Yellow & White wire connecting (under the main frame, above the carburetors) to the Boyer unit white wire AND to the relay terminal C-4. In the new wire between that T junction and the relay I have a 7.5Amp (US rated) fuse. So I should splice in a diode in the Yellow and White wire say just before the T junction e.g. "before" meaning facing the front of the bike not back to the Boyer unit which is sitting behind the battery? And it shld be installed so that the black Cathode faces the front and the red Anode faces back toward the Boyer, so that current cannot go forward to the kill switch?
Incidentally these diodes I got -the thickness of the wires emanating from them is OK , about same as the actual metal wires in gauge 18 wires, but the diode itself is so tiny it is hard to believe they can handle any current without blowing up or melting. Fascinating little buggers. I feel like I am a student in electricity 101. Thanks for being the teacher.
Originally Posted by Randy M
I have the Yellow & White wire connecting (under the main frame, above the carburetors) to the Boyer unit white wire AND to the relay terminal C-4. In the new wire between that T junction and the relay I have a 7.5Amp (US rated) fuse. So I should splice in a diode in the Yellow and White wire say just before the T junction e.g. "before" meaning facing the front of the bike not back to the Boyer unit which is sitting behind the battery?

Yes.


Originally Posted by Randy M
And it shld be installed so that the black Cathode faces the front and the red Anode faces back toward the Boyer, so that current cannot go forward to the kill switch?

Yes.
Hi Randy,

Originally Posted by Randy M
I have the Yellow & White wire connecting (under the main frame, above the carburetors) to the Boyer unit white wire AND to the relay terminal C-4.
This is wrong. The White wire into the Boyer-Bransden "Transistor Box" should be connected only to the White/Yellow wire from the handlebar kill switch.

Starter relay C4 is (should be) only 'live' when the starter button on the handlebar is pressed, this is (should be) the only thing that operates the relay. I'm assuming you aren't intending to ride with the starter button pressed constantly? If so, connecting relay C4 to the B-B Transistor Box White wire does not serve any useful purpose.

From http://www.boyerbransden.com/pdf/KIT00054__BOX00021_.pdf:-

Quote
General Data:
7) The T160 machine has ... a ballast resistor fitted in the circuit.
This must be removed and the white ignition box wire connected to the live wire feeding it with the ignition on.
... the "live wire feeding it [the ballast resistor] with the ignition on" is the White/Yellow wire from the handlebar kill switch.

Originally Posted by Randy M
In the new wire between that T junction and the relay I have a 7.5Amp (US rated) fuse.
The wire from relay terminal C4 was/is [b]only[/b] to bypass the ballast resistor when the electric starter is in use.

As the ballast resistor is removed when any electronic ignition is fitted, relay terminal C4 and any wire from it to the ignition become redundant.

Therefore, there should not be any "T junction" - the White wire into the B-B Transistor Box should simply and only make an end-on junction with the White/Yellow wire from the handlebar kill switch.

A 7.5A fuse only for the electronic ignition can be fittd anywhere between the kill switch and - in your case - the B-B Transistor Box; a convenient place to fit the fuse is in the end-on junction between the Transistor Box White wire and the kill switch White/Yellow wire.

Originally Posted by Randy M
diodes
Fascinating little buggers.
Is your T160 a bike to ride or just an exercise in seeing how complicated you can make the electrics?

Originally Posted by Randy M
I should splice in a diode in the Yellow and White wire
A diode between the kill switch and the B-B Transistor Box cannot and does not serve any useful purpose on a bike to ride.

Hth.

Regards,
Originally Posted by Stuart
Originally Posted by Randy M
I have the Yellow & White wire connecting (under the main frame, above the carburetors) to the Boyer unit white wire AND to the relay terminal C-4.
This is wrong. The White wire into the Boyer-Bransden "Transistor Box" should be connected only to the White/Yellow wire from the handlebar kill switch.

Starter relay C4 is (should be) only 'live' when the starter button on the handlebar is pressed, this is (should be) the only thing that operates the relay.


There's been no suggestion (or need) to "operate the relay" another way.


Originally Posted by Stuart
I'm assuming you aren't intending to ride with the starter button pressed constantly?


Randy shouldn't have to. When the starter button is released the Boyer box should continue to be fed by white/yellow from the kill switch same as would happen for the original points (and ballast bypass) system.


Originally Posted by Stuart
If so, connecting relay C4 to the B-B Transistor Box White wire does not serve any useful purpose.


It can, and apparently does as the Boyer will get direct battery voltage from C4 whilst the starter motor is in operation (and which Randy has said, works) just as if it was powered from a relay* so the Boyer box isn't reliant on the available volts from the ignition circuit, but I agree it's not an ideal situation as it is compensating for an excessive voltage drop in the ignition circuit during starter motor operation.

*(An alternative would be to power the ignition from a relay then the C4 connection wouldn't be required).



Originally Posted by Stuart
Originally Posted by Randy M
In the new wire between that T junction and the relay I have a 7.5Amp (US rated) fuse.
The wire from relay terminal C4 was/is [b]only[/b] to bypass the ballast resistor when the electric starter is in use.

As the ballast resistor is removed when any electronic ignition is fitted, relay terminal C4 and any wire from it to the ignition become redundant.


Therefore, there should not be any "T junction" - the White wire into the B-B Transistor Box should simply and only make an end-on junction with the White/Yellow wire from the handlebar kill switch.

Under normal circumstances I'd agree, however, connecting C4 to Boyer white as an auxiliary feed with apparently less voltage drop seems to be the only way Randy can get sparks during starter motor operation.


Originally Posted by Stuart
A 7.5A fuse only for the electronic ignition can be fittd anywhere between the kill switch and - in your case - the B-B Transistor Box; a convenient place to fit the fuse is in the end-on junction between the Transistor Box White wire and the kill switch White/Yellow wire.

That's not the intention. As quinten mentioned previously, the fuse preferably needs to go in the C4 wire.:

Originally Posted by quinten
"relay terminal at C1 is an unfused battery connection .
when the starter relay is energized ... C2 an C4 are contacted and have
a fairly Direct battery connect .
... if it solves the problem ... fuse between C4 and Boyer box white"


"C4 should only be hot when the start button activates the starter relay .
the fuse needs to protect against overloading the kill-switch ( in a couple of unexpected scenarios )
( there is a possibility for current to go both ways when the start button is pressed )"



Originally Posted by Stuart
Originally Posted by Randy M
diodes
Fascinating little buggers.
Is your T160 a bike to ride or just an exercise in seeing how complicated you can make the electrics?

However, it seems the only way this Boyer will spark during starter motor operation.

Originally Posted by Stuart
Originally Posted by Randy M
I should splice in a diode in the Yellow and White wire
A diode between the kill switch and the B-B Transistor Box cannot and does not serve any useful purpose on a bike to ride.

As quinten mentioned, if C4 is added" "there is a possibility for current to go both ways when the start button is pressed" and a diode in WY should prevent that possibility.
try to keep up Stewart ... read the whole thread .
no one needs rescuing .

the right way to do would be to clean up the wiring from key switch , to kill ... to boyer box
... so that there isnt excessive voltage drop , even when the starter load is added .
the wiring is old with previous owner modifications .

pulling the gas tank to expose the harness... opening the headlight ... pulling apart the handlebar cluster switch
is not a walk in the park
the OP did not choose to pursue this path ... when a wiring alternative presented itself
that is ultimately more convenient .

jumping extra power when the C4 terminal is live ... is a creative alternative ... i think the credit goes to lab .
but this seemingly simple fix ... created some new problems .

C4 is and unfused battery connect ... so i recomended a fuse be added . .. it protects the kill switch
more than the boyer . .. the boyer protects itself if it's wired correctly .

the diode prevents power from going backwards into kill and back into the harness ... there appeared to be some unexpected idiot lights
being back fed ... at one point ...
how much power can the kill switch hande ? ... are the old contacts sticking ?
but the diode will also drop 0.7 Volts ... all the time the boyer is powered from the kill ... I'd probably leave out the diode ,
and let the fuse limit what can pass back into the harness ... if the fuse blows all that is lost is
the extra Parallel Power feed ... when C4 is hot ... and the fix is disabled , back to square one .
Originally Posted by quinten
jumping extra power when the C4 terminal is live ... is a creative alternative ... i think the credit goes to lab .

I'm sure it was mentioned on the TOL forum some time ago so I can't take credit for it.
Hi everyone, Randy here. I seemed to have stirred up quite a lively discussion. To add to this hornet's nest: A friend who is a biker (Matchless, Norton) and has a Masters of Engineering (more on metallurgy than electronics but he seems to know a lot about electricity) thinks the reason the idiot lights came on was more likely a failing ignition switch, and no need for a diode between the kill switch and the B-B "box". The ign switch on his 1974 Commando recently failed and the bike has only 1800 miles on it (he bought it new) and has barely been ridden in last 25 years. Lucas "quality" I suppose. He also thinks that since the zenor diode is a diode adding another one is redundant, although he has not seen a wiring diagram. (The ZD is NOT where L.A.B. suggested it be located.) .
When I get back to the bike in the Spring I will see how often this happens and if more than when I first hook up the battery will try the diode remedy and if that fails then a new ign swtch. Just to be clear the lights did not go on when starter button pushed, just when I hooked up the battery (key in OFF position) after removing it to install and test the fused wire going from C-4 to the White & Yellow from kill switch which I had soldered to the white B-B input wire.
Also lots of talk about the wiring being messed up on my bike but it does have good original wiring per the stock wiring diagram except for what the Previous Owner did to install the Boyer (correctly from what i can tell from the B-B instruction sheet and diagrams provided in this thread; and it DID run OK for about 6 years, other than a) vibration and b) the U.S. made 867 kit it came with had very thin barrels and I got a big hole in one piston, the same cylinder that still likes to self-ignite in the muffler after ign is switched off, and c) the PWK carbs I installed would not idle under 2500 rpm in summer heat, same carb issue on a friend's Norton) A few years ago I replaced but did not alter the scheme of some rear turn signal wires, replaced the flasher unit and some sloppy headlamp bulb plug connection, and I know a previous expert mechanic replaced the solenoid and the partly snapped off red plastic kill tab but presumably did not change anything else inside the switch and would have if he has noticed it needed it. There is 13.7 volts where the White & Yellow wire connects to the white wire that goes to the B-B "box" so I do not think there is any significant "drain" from bad wires, switches or connections to search for.
Originally Posted by Randy M
To add to this hornet's nest: A friend who is a biker (Matchless, Norton) and has a Masters of Engineering (more on metallurgy than electronics but he seems to know a lot about electricity) thinks the reason the idiot lights came on was more likely a failing ignition switch, and no need for a diode between the kill switch and the B-B "box".

As several of us have repeatedly suggested, there is a fault somewhere in the ignition feed and which could be inside the ignition switch.

If you find the fault and fix it then there should be no need for a diode or the extra C4 wire to get sparks during starter motor operation.



Originally Posted by Randy M
The ign switch on his 1974 Commando recently failed and the bike has only 1800 miles on it (he bought it new) and has barely been ridden in last 25 years. Lucas "quality" I suppose. He also thinks that since the zenor diode is a diode adding another one is redundant, although he has not seen a wiring diagram.

I haven't suggested you fit a "Zener" diode and neither has anyone else.


Originally Posted by Randy M
(The ZD is NOT where L.A.B. suggested it be located.).

I haven't suggested locating a Zener diode anywhere, only a diode.

The standard Zener diode would normally be attached to the finned heatsink below the headlamp and is the voltage regulator part of the charging system, not part the ignition system although a faulty Zener could possibly cause a voltage 'drain', but your voltage readings seem to disprove that.
I have original Lucas switches that are still working but I do not have them sitting around unused for 25 years. Possibly it became corroded from non-use? They are not exactly sealed switches.
13.7 volts is when the engine is running? You do not get voltage that high with a lead-acid battery without the generator putting out. Using a LiFePO4?
© Britbike forum