Multimeter results for stator test

[Kev D]

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.
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

   
     

[Coddy]

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

[rhyatt]

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

[Kev D]

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.





   



     
         

[limeyrob]

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.

[rhyatt]

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 !!!!!

[Kev D]

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

[rhyatt]

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

[Kev D]

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?

[rhyatt]

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.

[Derek996]

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.

[Kev D]

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😃

[rhyatt]

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

[Kev D]

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
       

[Derek996]

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.