1975 Mk3 Commando ignition warning light problem

chrisf1

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Aug 23, 2015
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Hi again everyone more problems with my bike in the title, for some reason the ignition warning light is staying on, since getting the bike a few months back and during this time until now the light was going out as it should with a slight increase in revs, that is with a new high output single phase stator, and new podtronics regulator and rectifier replacement system, last week it has started staying on regardless of revs, I am suspicious of the WLA (Warning light assimilator) which I have been told can be a problem the bike is fitted with the solid state one of these being a Mk3 so I have ordered a new one just in case but would welcome any advice to cure this my friend who is quite well up on auto electrics assures me the bike is giving out a charge but cannot find out why the light is staying on many thanks for your replies Chris
 
Check the output across the battery terminals with a multimeter. Very the revs and watch it increase.
If you don’t have one, add it to the tool collection. It will get used a lot.
 
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I have had the same problem after fitting a Trispark Mosfet regulator to my Mk3, after replacing 3 warning light assimilators I emailed Trispark, Steve Kelly replied that the OE style assimilator is not compatible with modern type regulators, in my case the warning light would work correctly when the battery was accepting a charge but when the battery was fully charged the Reg would do its job and stop the charge therefor the red light would stay on, I confirmed this by switching my lights on which placed a drain on the battery.
 
possm said:
I have had the same problem after fitting a Trispark Mosfet regulator to my Mk3, after replacing 3 warning light assimilators I emailed Trispark, Steve Kelly replied that the OE style assimilator is not compatible with modern type regulators, in my case the warning light would work correctly when the battery was accepting a charge but when the battery was fully charged the Reg would do its job and stop the charge therefor the red light would stay on, I confirmed this by switching my lights on which placed a drain on the battery.
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That sounds a reasonble explanation as my battery is new and is left on the optimate did you solve the problem if so how or revert back to original charging equipment thanks for the reply
 
Basically I was p-ed off as there was nothing mentioned in Their sales or fitting literature and as I was finishing a complete rebuild on a bike I had brought in pieces there was no way I wanted to strip half the bike to fit a modern type assimilator, so as I run a Ctek trickle charge set with a plug with 3 LEDs connected to the battery which is under the seat and is always green [above 80%] I disconnected the wire to the warning light, my battery is a YTX16BS and the bike starts great.
 
possm said:
Basically I was p-ed off as there was nothing mentioned in Their sales or fitting literature and as I was finishing a complete rebuild on a bike I had brought in pieces there was no way I wanted to strip half the bike to fit a modern type assimilator, so as I run a Ctek trickle charge set with a plug with 3 LEDs connected to the battery which is under the seat and is always green [above 80%] I disconnected the wire to the warning light, my battery is a YTX16BS and the bike starts great.
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I understand your frustration and am not trying to minimize it.

Look at the bottom of this page: https://www.trispark.com.au/technical/

The Norton assimilator is a stupid device that provides almost info. In a nutshell, it tells you that your rotor is spinning in your stator and making some AC power. It tells you nothing about battery charging. Even with the original bridge rectifier(s) and Zener(s), it really tells you nothing useful. Well, that's not 100% true it tells you your ignition is on. I delete from every bike I build and put in Don Pender's oil pressure switch connected to the red light. Still tells you your ignition is on but also something useful - low oil pressure.
 
Mart UK said:
I'm confused. What is the warning light telling me?
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With the standard assimilator, when the light goes out it is indicating there is some AC output from the alternator but doesn't indicate if the battery is charging or not.
 
Hi everyone and thanks for all your input I have decided the best way to solve this is to go back to the original rectifier and contol box and the moral of the story is ( if it ain't broke don't fix it )
 
chrisf1 said:
Hi everyone and thanks for all your input I have decided the best way to solve this is to go back to the original rectifier and contol box
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There's no original (voltage) control "box" on the 850 Mk3 (or any other model Commando). The (twin 850 Mk3) Zener diodes are the voltage regulation.
1975 Mk3 Commando ignition warning light problem
 
I have now refitted both zener diodes back where they came from a new stator and tried a new WLA but my light is still staying on, it dims as the revs increase I have checked the charging circuit and it is throwing out 14.5 volts at 2k to 2.5k revs someone please help me, Electrickery is really not my thing you cannot see it or smell it and it still bites
 
chrisf1 said:
I have now refitted both zener diodes back where they came from a new stator and tried a new WLA but my light is still staying on, it dims as the revs increase I have checked the charging circuit and it is throwing out 14.5 volts at 2k to 2.5k revs
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The AC output (from both stator wires) that trigger the Mk3 assimilator to switch off the charge warning lamp comes directly from the stator so the WLA operates independently of the charging circuit.

The only thing I can think of (so far) that could possibly cause the lamp to glow (assuming it's not the Canadian model 06-6392 WLA) could be a bad connection or broken wire between where the assimilator white/green (WG) and green yellow (GY) feed wires connect to the same WG and GY stator output wires at two female double common connectors and Edit: both should have a third matching WG and GY wire that go to the (2DV 406) rectifier, so three WG connected to one double common and three GY to the other.

I see you've referred to the two Zeners as "2 rectifiers" on the NOC forum which might cause some confusion.
 
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I stand corrected I meant zener diodes, I hate electrickery you cannot see or smell it and it still bites and is getting more expensive daily
 
"you cannot see or smell it and it still bites"

Yup.......
 
Hi Chrisf1,

I had the same problem on my MK3. I fitted a battery condition led instead of the warning lamp and problem was sorted.

ELLIS
 
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