Hello. I posted a while ago about quirky the behaviour of my Victor .
Mainly it's ability to pop into life at a dab on the lever one minute and then make me look like wally with bangs and kick-backs at others.
A test run after what turned out to be fruitless fiddling actually found me bobbling past the meeting place of the local bsaoc branch. I almost plucked up the courage to stop on the way back to introduce myself.
As it happened l lost my lights so went straight home.
I'm one of those people who own a multimeter but have never done more that look for missing or incoming volts.
Anyway l ventured ignorantly into the world of ohms and came up with these readings from the stator.
l would be very grateful for comments from those who actually know how to interpret these figures. I fear the worst though.Screenshot_20260902_214829_Gallery.jpg
The ignition system is an Electrex STK 100DC . It was fitted by the previous owner but the bike never saw the road and sat for two or three years.
If my understanding of how to test the reg/rectifier is right . It's duff!
Thank you
I would suggest contacting Electrex and get some technical stats from them for your model as they don't list it on their website.
https://www.electrexworld.co.uk/acatalog/Road-Bike-Ignition-Systems-1.html (https://www.electrexworld.co.uk/acatalog/Road-Bike-Ignition-Systems-1.html)
It seems you have a 2 wire alternator stator and these 2 stator wires bring the AC from the stator to the 2 x yellows from the R/Rec.
If you can get it running , put your meter on AC volts and check the output from the stator (momentarily unplug 1 of the RR yellows), it can be about 30 volts AC when running.
If you get a decent AC then plug the yellows back in and check if the DC voltage at the battery rises.
Battery volts should be about 12.5 standing still and about 14v when running.
I assume the red and black RR wires are correctly wired, fused etc and ultimately go to the battery to charge it.
If you have AC going into the RR and the battery volts not rising , the your RR is defective
on your readings, you were looking "into" the R/R and there are diodes within this unit which would give you the 0 ohms on the yellows
Quote from: rhyatt on 03 Sep, 2026, 08:00 It seems you have a 2 wire alternator stator and these 2 stator wires bring the AC from the stator to the 2 x yellows from the R/Rec.
If you can get it running , put your meter on AC volts and check the output from the stator (momentarily unplug 1 of the RR yellows), it can be about 30 volts AC when running.
If you get a decent AC then plug the yellows back in and check if the DC voltage at the battery rises.
Battery volts should be about 12.5 standing still and about 14v when running.
I assume the red and black RR wires are correctly wired, fused etc and ultimately go to the battery to charge it.
If you have AC going into the RR and the battery volts not rising , the your RR is defective
on your readings, you were looking "into" the R/R and there are diodes within this unit which would give you the 0 ohms on the yellows
Thanks Rhyatt.
The tank's off ,awaiting a new tap so l can't run the bike at the moment.
Before taking it off though l did a voltage check with the engine running which indicated the battery wasn't charging.
I hoped for a simple solution like a loose connection but couldn't find any obvious problem .
So it was into the Ohms.
I have an unused generic "British bike" reg / rec in the shed but held back from fitting it in case Electrex used a special one .
Having checked their site ,the RR02 unit fitted to my bike is described as being universal.
In hindsight of course l should've thought to test straight from the stator at the time ; while the bike was running .
The lighting and charging system is independent of the ignition system.
The ignition runs direct from the alternator to Cdi .
l'm wondering if an ongoing problem with the stator could be the cause of the increasingly inconsistent starting, shin- kickers , signs of unburnt fuel and.... spectator amusement.
If it is intermittent and there's no obvious bad connections check the wires where they come out of the stators and where they go though the case. Vibration can break the copper inner with no external signs and cause an intermittent connection. Put an ohm meter on and wiggle the cables hard.
there are lots of 4 wire R/R around
assuming your spare one is a 12v unit and has 4 wires --- 2 x yellow (AC) and 1 x red (+ve DC output)and 1 x black (-ve DC output)
the reds and blacks outputs can be used either way round depending if you have a +ve or _ ve earth on your bike.
when you are up and running again , try this spare one out and check for the voltage rises and falls
even if it is not running, a decent kick with the spark plug out will generate a good couple of volts AC across the 2 stator wires.
or if you are feeling energetic , put it into 2 nd gear and push it up the drive - see what comes out then !!!!!
Quote from: rhyatt on 03 Sep, 2026, 15:24 there are lots of 4 wire R/R around
assuming your spare one is a 12v unit and has 4 wires --- 2 x yellow (AC) and 1 x red (+ve DC output)and 1 x black (-ve DC output)
the reds and blacks outputs can be used either way round depending if you have a +ve or _ ve earth on your bike.
when you are up and running again , try this spare one out and check for the voltage rises and falls
even if it is not running, a decent kick with the spark plug out will generate a good couple of volts AC across the 2 stator wires.
or if you are feeling energetic , put it into 2 nd gear and push it up the drive - see what comes out then !!!!!
Thanks to everyone who has posted.
I'll try to enlist another set of hands at the weekend for the pushing up the drive or kicking-over test.
I'll compare the Ohm readings from the spare new Reg/rec with those of the one from the bike too.
Thanks everyone.
Kev
Dont forget looking INTO the r/r on ohms is not easy due to the internal diode network.
Just the simple AC checks and battery volts rising hopefully
Quote from: rhyatt on 04 Sep, 2026, 18:48 Dont forget looking INTO the r/r on ohms is not easy due to the internal diode network.
Just the simple AC checks and battery volts rising hopefully
Hopefully 😃
Would testing the reg/ rec in the multimeter's "diode" setting give any clues?
It's not easy , given the diode arrangement unfortunately.
Normal diagnostics of bike RR units is limited to confirming AC going in and battery voltage rising.
And hopefully covering what the lights and ignition are consuming.
If the alternator is producing sufficient volts, usually around 15Vac per 1,000 rpm and the battery voltage isn't rising then the regulator must be faulty. But before condemning it check that the connections from the regulator to the battery and ground are sound.
Ah.New fuel tap arrived so l was able to run the bike this morning.
Battery showed no change in volts.
Testing the two charging wires from the stator resulted in a desultery reading of "000" from each of them ...
The bike started first poke - not unusual- and then did a perfect warm start ten minutes later - an increasingly less certain event of late. Probably because nobody was watching.
So the stator was clearly knocking out power in the ignition department .
If the charging side has broken ,could the ignition side be
"on its way out" ?
Starting has become increasingly erratic and in another post l mentioned signs of unburnt fuel. This led me to set carburation by the book and check timing.
Any way l hope l'm not boring folk with my amateur diagnostics and requests for advice .
Thank you😃
We're you on the AC volts scale and we know you have a 2 wire stator.
So , put your meter on AC volts and 1 crocodile clip on each of the 2 stator wires.
Start it and see what ac volts comes out , hopefully 30v or so
Quote from: rhyatt on 05 Sep, 2026, 14:24 We're you on the AC volts scale and we know you have a 2 wire stator.
So , put your meter on AC volts and 1 crocodile clip on each of the 2 stator wires.
Start it and see what ac volts comes out , hopefully 30v or so
Thanks again Rhyatt.
Your prompting made me realise
I have to confess to a schoolboy error. In that l previously tested the stator charging output on the DC setting🤦�♂️!
Just done the sane test on the AC setting
Still no volts.
Tracing the wires back towards the stator I removed the loom tape to reveal that the two yellow wires from the stator had been extended but the plastic shrouds that go over such junctions seemed to have slipped off.
Thus the bare connectors on each wire were touching each other; bound together by the loom tape in fact.
So separate and insulate joints . Engine on ...
Select AC volts on test meter.
Result = Joining the wires via the meter does nothing.
Running one wire to earth via the meter does nothing.
But running the other yellow wire to earth makes 20v or so at fast tick over.
Reconnecting the wires to the rectifier has resulted in a battery that shows a rise to over 13 volts at fast tick over.
So l have a charging system.
But has anyone any thoughts observations or advice regarding the non productive stator wire?
If l've missed something else obvious please say so!
Writing this thread and reading the replies has been very useful.
Thank you
Kev
There should be volts across the 2 yellow wires and none of them should produce volts when measured across earth. There should be infinite resistance between any of the yellow wires and earth.
That you get no output across the 2 yellow wires yet 20V across one of them and earth but nothing from the other one would suggest that the the windings have a short to earth and an internal open circuit although I can't see how that would allow it to charge. Perhaps you should ask Electrex for their thoughts.
You have a 2 wire stator we know , but is this a brand new stator with 2 yellows coming out of it.
Or
Has a PO fitted a 2 wire 12volt lucas encapsulated stator
Or
Has a PO modified an original 6 volt 3 wire stator by joining a certain pair of wires together to convert a 6v into 12v
I ask this because the original 3 wire stator had green/green yellow/green white coming from the stator.
And my 12v lucas 2 wire stator had similar colours coming out of its encapsulated stator
In his first post KevD states that the bike is fitted with an Electrex STK-100DC alternator/igntion system. This has a 2 wire alternator for charging and an independent CDI igntion system.
This is the wiring diagram below. For positive earth it it much the same except the battery connections are reversed.
looking a bit deeper into this issue and I find this diagram which is clearly showing your kit---
https://www.dropbox.com/scl/fi/hpbo35ld32zbakn5it352/STK-100D.pdf?rlkey=z8m3sb5yo4jacimsv4wi4s5j6&e=1&dl=0
a 5 wire stator (their own unique one) with 2 yellows going into their RR02 reg/rec
Is this how your bike is wired up ?
the AC principle still stands - namely AC with you meter across their 2 yellows - yes or no AC output -- mustn't involve earth or anything
you could try 20 or 200 ohms scale and look INTO the stator to see if there is continuity inside the yellow windings
Quote from: rhyatt on 06 Sep, 2026, 16:29 looking a bit deeper into this issue and I find this diagram which is clearly showing your kit---
https://www.dropbox.com/scl/fi/hpbo35ld32zbakn5it352/STK-100D.pdf?rlkey=z8m3sb5yo4jacimsv4wi4s5j6&e=1&dl=0
a 5 wire stator (their own unique one) with 2 yellows going into their RR02 reg/rec
Is this how your bike is wired up ?
the AC principle still stands - namely AC with you meter across their 2 yellows - yes or no AC output -- mustn't involve earth or anything
you could try 20 or 200 ohms scale and look INTO the stator to see if there is continuity inside the yellow windings
Yes that's how my bike is wired ,except it's positive earth.
ok , then if it is not charging , which i think is the issue , it can only be 3 sources--
1 no AC coming out of the 2 yellow stator wires
2 you have AC at 1 but the RR is not doing anything with it and sending DC to the battery
3 a wiring issue
Quote from: rhyatt on 06 Sep, 2026, 17:28 ok , then if it is not charging , which i think is the issue , it can only be 3 sources--
1 no AC coming out of the 2 yellow stator wires
2 you have AC at 1 but the RR is not doing anything with it and sending DC to the battery
3 a wiring issue
The initial investigation started when l had no charge at the battery.
I (eventually)discovered that where the two yellow stator wires had been extended the joints were left uninsulated and were touching due to being bound together by the loom tape.
I separated these and insulated them from each other
I seem to have have AC from only one yellow stator wire but the battery is showing some charge now.
I went for a ride this afternoon with the lights on and the battery stayed charged!
The sketch shows what were the two uninsulated joints. Possibly the PO forgot to slide the plastic insulators over them before wrapping them in loom tape .
.Screenshot_20260906_200441_Gallery.jpg
But would this unintended connection between the yellow stator wires have caused my problem?
Or indeed damaged the stator?
I really appreciate everyone's patience in helping me .
Kev
that's good news if it is charging now
basic checks on voltages should be thus--
ignition off / lights off everything off , battery should show around 12.5 ish DC volts across its 2 + and - terminals
then running should bring the voltages across the battery up to around 14 DC volts ( ideally 14.2 ish)
BUT
a flattish battery will by definition , show a lower than 14 volts due to it absorbing some of the incoming charge until it eventually reaches 14.2 , then the regulator cuts off the incoming charge and dumps the surplus to earth in the form of heat(hence the finned body)
always conduct charging check on a fully charged battery obviates this "delay" period
a slightly longer ride with lights off and a volts check when you get home hopefully shows you 14 V dc
But would this unintended connection between the yellow stator wires have caused my problem?
absolutely - a shorting of the AC output will limit/negate what is going into the RR
damage to the stator- only time and the above volts checks will show you
as an aside , I had a RR that proved to be faulty by way of the internal diodes failing - it meant that the battery was discharging backwards through the RR diode into the stator winding and making the stator into an electro-magnet and trying to rotate the rotor/crank - took me a while to diagnose that !!
I think all you can do it ride it and see how it performs over a few weeks. The short could have done damage but not necessarily, its hard to know. If its charging, the lights are working, its not misfiring then indications are good but check the battery is not over gassing and if you get bulbs blowing there is probably a problem.
if the two yellows have shorted together it shouldn't have caused any problems as these simple alternators don't generate "into" a fault. The stator merely becomes a loop of wire with a magnet rotating within it.
Quote from: rhyatt on 07 Sep, 2026, 09:32 that's good news if it is charging now
basic checks on voltages should be thus--
ignition off / lights off everything off , battery should show around 12.5 ish DC volts across its 2 + and - terminals
then running should bring the voltages across the battery up to around 14 DC volts ( ideally 14.2 ish)
BUT
a flattish battery will by definition , show a lower than 14 volts due to it absorbing some of the incoming charge until it eventually reaches 14.2 , then the regulator cuts off the incoming charge and dumps the surplus to earth in the form of heat(hence the finned body)
always conduct charging check on a fully charged battery obviates this "delay" period
a slightly longer ride with lights off and a volts check when you get home hopefully shows you 14 V dc
But would this unintended connection between the yellow stator wires have caused my problem?
absolutely - a shorting of the AC output will limit/negate what is going into the RR
damage to the stator- only time and the above volts checks will show you
as an aside , I had a RR that proved to be faulty by way of the internal diodes failing - it meant that the battery was discharging backwards through the RR diode into the stator winding and making the stator into an electro-magnet and trying to rotate the rotor/crank - took me a while to diagnose that !!
Rhyatt. Thank you for your patience and advice. As you say time (and a volt test) will tell . Thanks again.
Quote from: limeyrob on 07 Sep, 2026, 10:50 I think all you can do it ride it and see how it performs over a few weeks. The short could have done damage but not necessarily, its hard to know. If its charging, the lights are working, its not misfiring then indications are good but check the battery is not over gassing and if you get bulbs blowing there is probably a problem.
limeyrob. Thank you. Sounds like a good excuse to put a few more running- in miles on the bike . I did notice a couple of really tiny glitchy misfires that felt electrical( if that makes sense) in the first hundred yards when l went out yesterday but nothing after that.l took the long route to a local bike show .
When l left a few hours later the bike started first kick( which saved me embarrassment in front of my mates and some rather hairy be-patched onlookers)and ran well on the way home .My fingers are so crossed they are knotted .
So far so good but if anything naughty shows up l have an idea of where to look.
Thanks to everybody who has chipped-in .
Kev