Hi all, I hope someone can help. please see below
I have fitted an electric starter to my A75R pretty painful right Knee and left hip has pushed me this way, I have fitted a Triumph T160V starter assembly with a new Starter motor and have fitted a Lucas type 22 ra relay ( I have changed this for a modern type also), the starter is wired correctly and turns the engine over but it will not start consistently, but will start on the Kick start with no problem the bike is running on a MK IV Boyer ignition with 6 Volt coils, looking online it seems the problem is the starter is pulling volts below the working capacity of the MK IV Boyer when cranking the bike on the starter the battery voltage drops to around 9.7 volts but I have fitted a separate battery supply to the Boyer and the problem still persist, I worked for Exide for many years as there Technical Manager so I know my way around batteries, I have a 140 CCA 9AH new Yuasa battery, I can squeeze in a 175CCA 14.5 Ah MB10U battery but I have also tried car battery 640 CCA 60Ah with no difference all batteries test good, again online people are saying that the Tri Spark system can resolve this but as I am not sure of what the problem actually is I do not want to spend a load of cash to find the problem persists, others online say changing the 6V coils to 4V coils and keep the current MK 4 Boyer may resolve the problem but I have no experience with 4 Volt coils, as stated above the bike kick starts no problem, (it just leaves me with a swollen Knee) but will also intermittently start on the electric start, I have no exhausted my knowledge, I hope someone can help, I just do not want to stop riding my Rocket 3.
Regards
John
As you already know, you have a large voltage drop. So much so you are starving the system. Check earth's also find what is drawing off all the current. I would suspect the starter motor. Otherwise go to 4 volt coils and a ballasted system like cars used to have.
I know you're well down the road with this, but the Madigan starter spins the motor like a top compared to the Lucas starter..... and I would guess draws a lot less current. But that is a guess. My R3 really spins with the Madigan starter whereas my mate's R3 with Lucas starter sounds like it's struggling....
I have had effectively the same problem with the similar starter on my Norton Electra. After much wailing and gnashing of teeth, I have tried various solutions. Much advice has been along the lines of "they never work, use the kickstart" which I'm afraid doesn't cut it. I too have Boyer Mk 4; on the advice of BB I tried 6 volt coils etc to no avail.
Finally I came to a similar analysis as you and I believe I now have a workable solution. In short, although BB say 10 volts is enough to fire the ignition, I believe the voltage is too low for a decent spark. So what I've done is to add another small 12v battery which only supplies the BB black box. It's brought into operation via a relay switched by the ignition switch, and charged via a voltage sensitive relay of they type usually used to charge motorhome leisure batteries.
I don't know if you can get at it but here is what I've built.
NOC forum (https://www.nortonownersclub.org/forum/starter-woes-yet-again)
It was starting first push of the button every day through the back end of the summer till I put it away for the winter. There are various other subsequent threads elaborating (and describing further issues) on the same forum. If you don't have access let me know and I'll send you some text - or post it here.
have you done a "volts drop test" between the battery Pos terminal and the solenoid and then the other side of the solenoid to the actual starter terminal and finally directly across the solenoid terminals themselves.
and then the neg side from the battery neg terminal to the stages of the earth (battery to frame and frame to engine>
basically working through each leg of the voltage paths and seeing where you are losing the voltages
(don't forget to disconnect the ignition when doing all these cranking based tests - you don't want it to actually start)
Quote from: rhyatt on 04 Nov, 2025, 16:30 have you done a "volts drop test" between the battery Pos terminal and the solenoid and then the other side of the solenoid to the actual starter terminal and finally directly across the solenoid terminals themselves.
and then the neg side from the battery neg terminal to the stages of the earth (battery to frame and frame to engine>
basically working through each leg of the voltage paths and seeing where you are losing the voltages
(don't forget to disconnect the ignition when doing all these cranking based tests - you don't want it to actually start)
I was once asked about a bored and stroked, tuned up Harley that was not starting on the button. All became clear when I asked if the starter cables were getting warm, "Yes!" they replied, and a change to thicker cables solved the problem.
Poole, is the starter motor not turning very quickly? If so and the cables are getting warm, thicker cables are at the very least part of the solution.
Thank you all for your input, it has given me a few new things to look at.
I actually did the voltage tests as described on my Electra. With a fully charged 9Ah, 120CCA battery I was seeing 12.7 volts at the BB box with no load and between 10.2 and 10.4 with the starter operating. I just don't believe this is enough to reliably operate the BB system. As suggested by Rog1 I have 10 sqmm cables for both supply and engine earth (very important and often overlooked).
It's also worth checking the starter motor itself - I believe the R3/Trident use the same basic motor as the Electra. Inside the brush end cover there should be a fibre insulating ring preventing shorting bwteen the brush leads and the casing. Some previous owner of my bike had replaced this with PVC tape resulting in, initially a partial short but eventually a complete short. This made the cables very hot!
Oddly enough, as I was trying different things, I tried the BB v3 black box that came with the bike originally and it worked perfectly well with my auxiliary battery setup. But then so it should being supplied as it is with a full 12.7 volts. You can waste a lot of money and time trying different things.......
As a yardstick on volts drop tests , you should not see any more than 0.5 v maximum at any section of the tests along each path.
When one breaks the actual test down , there are loads of segments , for example ---
Take the + side,
1)Battery lug itself to cable terminal.
2)Crimp to conductor
3)conductor to other end crimp
4)crimp to component fixing
The solenoid itself , one can go directly across the 2 heavy posts themselves and hopefully not see any more than 0.5v max on the meter.
It's surprising how much total volt drop is accumulated along each conductor.
Many modern cars ecus will not function below 10.5v and a few below 11v.
Given that the standing voltage of average 12.5v doesn't give a lot of leeway before a vehicle won't fire.
All these tests must be done when the vehicle is actually cranking ie working hard.
It must not start for this test
I don't think that voltage drop as describedis the problem here. It's the fact that the starter takes so much power that it drops the available voltage for the BB box below what it needs. Even with perfect conductors you'd get the same effect. Hence my use of an additional battery. Not a conventional solution I grant you but it works.
BB say their Mk 4 box works down to 10 volts but I'm afraid I don't believe that. I do wonder whether using a conventional Kettering system with points might actually be better here although of course that then raises issues of accurate and consistent timing etc.
Hi Iansoady
I have re-looked and checked all points from above, and all seems OK, so I set a car battery to power the starter and a separate 9ah bike battery to power the Boyer both being charged with separate battery optimizers, The R3 has started on the button all day today, so it seems it is the Boyer Mk 4, I guess now I must decide how I move forward, I downloaded you sketch, I think the diode is a Schottky barrier diode do you have the spec? I have looked on line for a Voltage sensitive relay the standard seems to be 12V 140A is this the type you used, at this moment the biggest issue is where to fit an Auxiliary battery, but I have moved forward a good pace, I would like to thank all for input.
I have a slightly better sketch here: rather than using a diode I've fitted a voltage sensitive relay (split charge relay) which kicks in at about 13.5 volts. As it's negative earth I've had to use it to drive a relay. I got this one from my local electrical supplier:
https://www.almsolutions.co.uk/battery-products/split-charge-relays/automatic-vsr-dual-split-charge-relay-30a (https://www.almsolutions.co.uk/battery-products/split-charge-relays/automatic-vsr-dual-split-charge-relay-30a)
I do not believe that the BB unit is fit for purpose with an electric start machine.
(https://www.iansoady.org.uk/Norton%20Electra/images/full%20wiring.jpg)
Iansoady, thank you for the information and diagram, I will try this, again thank you for all you help. Regards John
Just for information, this is the auxiliary battery I fitted. It doesn't need to be huge as it's only driving the ignition and is being charged as soon as the engine is running. It fitted in the toolbox of the Electra (the main battery is between the toolbox and oil tank).
https://www.tayna.co.uk/industrial-batteries/numax/lsla4-5-12/
Would it be possible to put a DC to DC voltage booster in parallel to supply the BB unit? Connected to the starter feed so its only live when cranking? These are small-ish and cheap so you could experiment. You could set it for 10v input 12.5 output.
I tried that in one of my earlier experiments. Unfortunately they don't output a fixed voltage but only one proportionate to the input voltage. Or at least the one I tried was like that.
Thanks for letting me know, I was looking at them for another project. I think you've just saved me some time and frustration!
Actually it may be relevant to the starter. I have an old Land Rover converted to a camper and it has a Webasto diesel heater. These are set to lock out at 10.5 V but for years I've been having lock out problems. I got the software and ran live voltages and it was dropping to 9.5V when the battery terminal was at 11 V. I then did volts at every connection and while there was no obvious culprit there were a lot of small drops. The problem was that the heaters switch between drawing 2 amps and about 10 amps and the voltage only has to drop for milliseconds for a lock out.
I doubled the size of every cable and soldered every connection. I gained 2 volts and its never locked out since. I think the biggest gains came from removing any screwed terminals and the fuse.
I've got a made in coventry starter on my R3 with boyer ignition using a yeasu ytx14 12.6Ah 200cca battery no problem starting,
I've rerouted ALL earth's to the engine, so the only earth comes from engine/starter to the battery, this means boyer get max voltage, also i have state of the art regulator rectifier for max battery charging stand alone 40amp relay worked from tha ignition key,
This battery is the biggest that I could fit it the battery tray
Interesting Vince. Have you ever measured the voltage at the BB box when cranking? Mine was between 10.1 and 10.4 which I don't believe is enough....
+ 1 to earths to the engine. The paint on the frame and the ally case to steel frame can cause high resistance.
Yes, I always run a dedicated earth to a convenient engine stud. I also add an earth cable to the headlamp / handlebars.
I'm not familiar with the BBunit as fitted to the triples. On parallel twins like A10s, Norton Electras etc there is a spark every engine revolution hence a wasted spart in the cylinder not at compression. How is the triple arranged?
Hello All
I owned a T160 in my youth for 19 years & took interest in all technical articles written about these machines/engines.
The few British bikes that had electric starters all seem to
be compromised due to component efficiency with available battery output.
I don't claim authorship of the following as I came across it in an article decades ago.
Sadly I cannot remember where but in essence the idea was to take a cable from the starter post that becomes live when the start button is pressed to the coils.
Therefore the coils will access the same voltage as the start system when it is cranking.
It is essential to include a diode in the cable so the current can only flow towards the coils & not back to the starter.
The same result could be obtained by using a relay activated from the start button to feed the coils direct from the battery but we then add another component to the system that's not really needed.
With a decent battery & charging system this eliminates the need for auxiliary battery's & other components that appear to offer a solution but add more weight to an already heavy bike.
In my macho youth I removed the starter system as my right leg was sufficient & it shed a good deal of weight so I never tried this idea but 40 years later I'd be giving this a go if I still had the bike.
Hope this helps
Regards to all
Steve
Quote from: Lancashire steve on 30 Nov, 2025, 10:53 H.... in essence the idea was to take a cable from the starter post that becomes live when the start button is pressed to the coils.
Therefore the coils will access the same voltage as the start system when it is cranking.
You're still going to get a low voltage as the starter motor is sucking all the power from the battery. When I measured the voltage at the battery on my Electra it dropped to less than 10.4 volts (varying slightly as the motor turned) which in my view just wasn't enough to operate the BB system effectively.
I accept my auxiliary battery solution adds (slight) weight and some added complexity but I can live with that if it gives me reliable electric starting. Which is why I bought the bike in the first place.
Hello All
First of all I would say that Ian's auxiliary battery solution is a well thought out & practical solution.
The main culprit seems to be starter efficiency & aftermarket starters (madigan) for example seem to have proven this.
If a big enough modern battery could be squeezed in then possibly the simpler idea mentioned in my previous contribution may be effective.
Of course it could be expanded/modified to take a supply back to the BB unit as well as the coils.
I just thought it was an idea not to be lost for those more electrically savvy than myself to possibly consider/make use of.
Regards everyone
Steve
Some electronic ignitions do not work at low voltages,particularly the Boyer analog system. The T160 has a dual contact relay that bypasses the coil ballast resistor when the starter is engaged. It uses 6 volt coils, not 12 volt.
On a Boyer analog ignition a voltage booster is needed to keep the voltage above the lower limit. One type is an oscillator charge pump, a lm555 timer putting pulses into a charge capacitor which is supplying power to the Boyer box. I do not know of any off the shelf charge pumps available.
There are DC/DC converters such as this one:
https://recom-power.com/pdf/Econoline/R1M.pdf
That have a 4.5V-18V input and provides 12V output at 90ma which would supply enough power for a Boyer analog.
I tried a cheap version of that dc/dc converter but found it wasn't properly regulated and its output was merely a variable related to the input voltage. And 90 mA is far too low - a Boyer will pull up to 4 or 5 amps at peak.
No, the DC/DC converter is only supplying power to the timing circuit, not the coils. I have not tried that one but people have used the LM555 timer charge pump with success.
I'm not sure how you can do that with the Boyer as there's only one live feed which supplies (indirectly) the coils. Although I don't know how the triple version works as I only have experience of the twins.
Maybe talking different Boyers. The analog Boyer has a power wire for the timing circuit. The coils are provided power directly from the ignition switch. The Boyer replaces the points providing the ground path for the coils.
Probably, the versions I'm familiar with are the Mk 3 and Mk 4 analogue systems.
Referring to this one:
But that shows the coils being fed from the BB box? Although I have to say my electronics knowledge is minimal at best.
No, not really. The Boyer is actually a negative ground system. If the positive lead to the Boyer were connected to a separate battery or charge pump, then the timing circuit would be separate from the coil driver.
They could have designed it with a PNP coil driver which would put the coils on the negative supply with the driver between the coils and the positive supply. I think at the time there were higher power NPN transistors available than PNP.