Flickering charging light

BERT · Oct 21, 2022

The last few rides, the charging light has flickered erratically at around 3000rpm. All the lights and switches are working as they should, including the charging light below 3k and above 3k. Could this be caused by the rotor rubbing the stator at a certain rpm? If so, I wonder if this could indicate a failing main bearing. The bike is being put away for winter after this weekend and any input would be appreciated as to what to look for.

marshg246 · Oct 21, 2022

If you still have the assimilator, it might simply mean it's going bad. If your battery is staying charged and you're not hearing noises, IMHO you should be thinking bad assimilator.

acadian · Oct 21, 2022

If the rotor were rubbing you will find metal particles in the primary oil. check for bad wiring

concours · Oct 21, 2022

BERT said:
The last few rides, the charging light has flickered erratically at around 3000rpm. All the lights and switches are working as they should, including the charging light below 3k and above 3k. Could this be caused by the rotor rubbing the stator at a certain rpm? If so, I wonder if this could indicate a failing main bearing. The bike is being put away for winter after this weekend and any input would be appreciated as to what to look for.

Put the volt meter across the battery terminals (or at the Tender plug)
1) engine off
2) engine idling headlight off, then headlight ON
3) engine at 2,000 RPM headlight ON
4) engine at 3,000 RPM
headlight ON
report back

nortonmargie · Oct 21, 2022

I had similar problems, put in a new assimilator and problems cured. NOTE: There are two different assimilators: the three prong unit for everything before Mark III's and the Mark III five prong unit. To make matters more fun, some Mark III's have the three prong unit. I went nuts trying to find where the five prong item was until I learned this.

BERT · Oct 21, 2022

I will test the charging system as suggested. Is the assimilator necessary for the engine to run if one gets in a pinch?

marshg246 · Oct 21, 2022

BERT said:
I will test the charging system as suggested. Is the assimilator necessary for the engine to run if one gets in a pinch?

It's not required to do anything but light the red light if the magnet is not spinning in the stator.

It does not tell you that the battery is charging - it only tells you that AC voltage is being made - nothing about the rest of the charging circuit.

Tornado · Oct 21, 2022

I got rid of the assimilator on my MKII. Ran a season or so without, then had the Zener go bad and over charged/bloated the battery one day. Installed a voltage monitor LED (SparkBright Eclipse) as that actually tells you what DC volts are reaching the battery so you know if it is charging.

There are a number of test procedures for all the electrics in Workshop manual. Worth doing some on your bike.

ILLF8ED · Oct 22, 2022

Tornado said:
I got rid of the assimilator on my MKII. Ran a season or so without, then had the Zener go bad and over charged/bloated the battery one day. Installed a voltage monitor LED (SparkBright Eclipse) as that actually tells you what DC volts are reaching the battery so you know if it is charging.

There are a number of test procedures for all the electrics in Workshop manual. Worth doing some on your bike.

I like it. The 10mm option, correct? Did you wire direct to the battery?

Tornado · Oct 22, 2022

ILLF8ED said:
I like it. The 10mm option, correct? Did you wire direct to the battery?

Can't recall if 10mm but it fits in the shell opening. I use the stock rubber boot "shade" thingie. A little dab of silicone seal to hold it firmly.
Originally wired to an on with ign wire within shell and a ground. But after having some anomalous readings and consulting with maker, was advised it is fine to go direct to battery. The draw is so low, milliamps, it would take a few months to drain significant power from a decent battery. Plus the led stays lit when parked up, fooling folks that there is some kind of anti theft device in place ;-)

ILLF8ED · Oct 22, 2022

Think I will order one.
Thanks

Alan L · Oct 22, 2022

I think the assimilator is a rather poor piece of electrical equipment.
Mine had failed for ages with the light remaining illuminated although the bike was charging.
I pulled it apart, all looked fine but it refused to play ball.
In rummaging through some autoparts I came across a voltage warning light unit from my Humber Imperial. The car, made in 65 is rather unusual in as much as it has a large alternator for it’s day (50 amp) but is positive earth. Anyway, the part looked identical to the Norton Assimilator apart from the fact it has a tag riveted on to it to mount it with a screw. I installed it and it worked perfectly.
Im not sure why Norton call it an assimilator because in the Humber (Rootes Group) manual it is called a Warning Light Control Unit.
Alan

marshg246 · Oct 22, 2022

Alan L said:
Im not sure why Norton call it an assimilator because in the Humber (Rootes Group) manual it is called a Warning Light Control Unit.
Alan

Fancy name for marketing to make is sound like it did something.

Or, maybe Lucas probably balked at making a headlight shell with 2 instead of 3 warning lights and Norton did want to add an oil pressure switch like the bigger companies had?

BERT · Oct 25, 2022

The voltmeter showed around 13.5 volts at the battery. The weather was so good Saturday, I took a chance and went for a good ride running without the headlight. The charging light did not flicker at 3k rpm as previously described. About 200 miles later, the charge light came on full time. Luckily I was close to a hardware store and borrowed a voltmeter. At the battery, the meter read 6v so I parked it and called for help. Back at home after a few days the battery (Shorai) came back up to 12v without starting the engine. I opened the primary for a look and may have found the problem. One of the 2 wires off the stator(Alton) had broken at the connector. The loose wire was not grounding out. Luckily there were no bits of rotor in there and the clearance is still good. Hopefully no other components got fried. The bike has a trispark ignition and podtronics regulator/rectifier with the integral filter. Also discovered a bad ground wire at the tender plug. A lesson was learned here: electrical issues do not magically disappear and best to deal with them no matter how nice the weather is and how late in the riding season it is...

Tornado · Oct 25, 2022

BERT said:
The voltmeter showed around 13.5 volts at the battery. The weather was so good Saturday, I took a chance and went for a good ride running without the headlight. The charging light did not flicker at 3k rpm as previously described. About 200 miles later, the charge light came on full time. Luckily I was close to a hardware store and borrowed a voltmeter. At the battery, the meter read 6v so I parked it and called for help. Back at home after a few days the battery (Shorai) came back up to 12v without starting the engine. I opened the primary for a look and may have found the problem. One of the 2 wires off the stator(Alton) had broken at the connector. The loose wire was not grounding out. Luckily there were no bits of rotor in there and the clearance is still good. Hopefully no other components got fried. The bike has a trispark ignition and podtronics regulator/rectifier with the integral filter. Also discovered a bad ground wire at the tender plug. A lesson was learned here: electrical issues do not magically disappear and best to deal with them no matter how nice the weather is and how late in the riding season it is...

The podtronics, I think you mean it has the integral capacitor, which can also be considered a filter, but it's primary purpose here is to provide power to the system if the battery fails...but alt has to be still making power.

BERT · Oct 26, 2022

I fixed the broken terminal and fired it up. The charging light is still constant on. The stator is putting out 20vAC at 2k and 36vAC at 4k therefore I believe the rotor and stator are good.At the battery, the voltage is showing a constant 11.5vDC no matter what the rpm.
(Tornado, yes I meant integral capacitor to get rid of the 3k misfire with the trispark)
Any ideas on what to check next? Thank you in advance.

Tornado · Oct 26, 2022

I believe the assimilator only provides warning for insufficient AC output, not DC from the reg/rec. There are some values for AC at specific rpms in the workshop manual. Also stator coil resistance values for testing it with a listed procedure. If all good, suspect something wrong with assimilator light connections or the unit itself. No DC above 11.5 v also not good. Confirm connections are good (any lucar bullets need to be thoroughly cleaned/corrosion removed or replaced). Try bypassing assimulator and giving pod direct feed off stator.
What is output direct off the podtronics at same rpms? Should increase up to about 14.8-15v max as the regulator kicks in to shunt excess.

BERT · Oct 28, 2022

Glad to report back the electrics have been fixed. I found a second broken wire at a connector that was held together with heat shrink tubing. Both had the wire soldered to the connector after crimping and the both failures were behind the solder on the wire. This leads me to believe soldering connectors on might not be robust enough. Thanks for the input.

Tornado · Oct 28, 2022

BERT said:
Glad to report back the electrics have been fixed. I found a second broken wire at a connector that was held together with heat shrink tubing. Both had the wire soldered to the connector after crimping and the both failures were behind the solder on the wire. This leads me to believe soldering connectors on might not be robust enough. Thanks for the input.

Yes there is a reason soldered wires are generally never found on motorcycles, cars or airplanes. Creates a stress point for metal fatigue to crack the wiring in vibration environments.

BERT · Oct 28, 2022

Tornado said:
Yes there is a reason soldered wires are generally never found on motorcycles, cars or airplanes. Creates a stress point for metal fatigue to crack the wiring in vibration environments.

Sounds like a winter project. Looking forward to learning more about the electrical system. Thanks for your help.

Flickering charging light

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