Ignition light

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Hi.
I have a Norton commando Roadster 850 fitted with a Alton Electric starter, however
I have recently changed my battery to a Motobatt MBYZ16HD 16AH 12V due to the previous battery only being 11AH and struggling to start the bike. Alton recommend 18 AH.
While being out on a 200 mile run today the headlight ignition light illuminated with about 20 miles to return home, I managed to carry on back without any problems.
Tomorrow I will have to investigate the problem, so I’d be glad if someone could give me a starting point in fault finding or possible causes.
Many Thanks.
 
Primary chain might have cut alternator wires in chain case.
 
Before you disturb your primary case, do a simple check with a multimeter across the battery - you want to find out what sort of voltages you are seeing in these three different conditions:

Your Motobatt MBYZ16HD is an AGM lead acid battery which has 2.1 volts per cell, so you should see around 12.6 volts at rest (ie with your multimeter across the battery and everything on the bike switched off)
With your engine started and idling with the lights off you should see 12 to 13 volts DC with your multimeter across the battery.​
Although the Alton alternator is marketed as 150 watts, Alton say themselves that it puts out around 90 watts at cruising speed, so at idle you may still see the red warning light flickering on occasionally.
With a healthy pair of coils, you are typically taking out more than your putting in with the standard charging system and the Alton is not much different (marginally better)
This is normal and good - exactly what you are looking for in a well balanced charging system.

At between 3,000 and 4,000 rpm you should see 14 to 15 volts DC with your multimeter across the battery.
This shows you are getting the right kind of charge to your battery.
You shouldn’t be seeing the red warning light at these RPMs.​

These three quick and simple checks will give us an idea where to start digging.
It could be a faulty warning light assimilator, a dead rectifier or regulator (or are you running a combined reg/rec like a Podtronics?) or indeed as @Deets55 says, your primary chain may have sliced through your stator wires.
 
It could be a faulty warning light assimilator, a dead rectifier or regulator (or are you running a combined reg/rec like a Podtronics?)
The Alton kit includes their proprietary 150 watt 3 phase alternator and I believe that they supply a Podtronics r/r to go with it.
 
@maylar that’s changed recently then!

They used to supply their own 150 watt single phase alternator (as I said in my reply) and whilst they recommended a Podtronics reg/rec they did not ship anything in the kit.

Their installation instructions cover connection to the original two wire charging system.
 
The Altons were 3-phase for a while, but they weren’t very good and were replaced by a single phase model.

The wiring diagrams on their website show two AC wires, so it’s unlikely it’s 3-phase.
 
My Commando was fitted with the Wassall Micro MK1 ignition kit when the Alton starter was fitted, It also has a Boyer power box bolted to one side of the battery tray, this i would say has been on for quite some time. I have not been able to find a Warning light Assimilator.
Neil
 
It also has a Boyer power box bolted to one side of the battery tray, this i would say has been on for quite some time. I have not been able to find a Warning light Assimilator.

The assimilator can't be used with the standard Boyer Power Box.

"If your Norton has a charging warning light simulator it must not be used with the power box, remove it. If the light control is required fit the power box type PBOX00166 with charging light control."
 
Not sure why Alton recommend a battery by AH, yes the larger the AH the longer it will last but spinning a starter needs CCA.

Cold Cranking Amps (CCA)
CCA is a rating used in the battery industry to define a battery's ability to start an engine in cold temperatures. Generally speaking, it is easier to start an engine in a warm environment than in a cold one. The rating refers to the number of amps a 12-volt battery can deliver at 0°F for 30 seconds while maintaining a voltage of at least 7.2 volts. The higher the CCA rating, the greater the starting power of the battery.
 
The Altons were 3-phase for a while, but they weren’t very good and were replaced by a single phase model.
The Altons were 3-phase for a while, but they weren’t very good and were replaced by a single phase model.

The wiring diagrams on their website show two AC wires, so it’s unlikely it’s 3-phase.

The wiring diagrams on their website show two AC wires, so it’s unlikely it’s 3-phase.

Ignore me. I was thinking of the Alton alternators that look like dynamos.
 
Not sure why Alton recommend a battery by AH, yes the larger the AH the longer it will last but spinning a starter needs CCA.
Alton give recommended AH and CCA values in their installation info, i am also not sure why they bother with the AH value. I have ignored that and fitted a smaller battery of the correct CCA.
 
On their site, they call for "just add a high output battery"

In their install guide they call for "at least equivalent to reference YTX 20LBS 12V 18Ah"

They do not mention CCA


As an aside, the Yuasa YTX20L-BS is a valve regulated lead acid - which is more leak proof than the original 'vented' lead acid batteries.
It's specs are:
  • Capacity Ah (20-HR): 18.9
  • CCA @ -18C: 270
I personally prefer AGM over and above VRLA batteries.
They are both lead acid, but in my experience, the AGM batteries seem to get through winters much better.


But we digress, and should all get back to helping Neil, the OP who has now probably given up on us being able to assist him and run away!
 
@maylar that’s changed recently then!

They used to supply their own 150 watt single phase alternator (as I said in my reply) and whilst they recommended a Podtronics reg/rec they did not ship anything in the kit.

Their installation instructions cover connection to the original two wire charging system.
Oops... my bad. I thought I saw a Podtronics in the parts breakdown in their install instructions, so I assumed...
 
I carried out the three tests on the battery using a Volt meter directly over the terminals.
Battery Voltage with the bike standing, no ignition on. 13.01 volts
Battery voltage with bike started and idling at 1500 rpm. 12.75 volts
The battery voltage was measured at 3000 rpm and was difficult to obtain a single value as the reading were erratic and giving off between 12 and 14 volts.
I also have a Battery status monitor fitted and this indicates that the alternator is charging, but how much is unclear.
From the results so far is it right to assume the Boyer Power Box regulator / Rectifier is at fault.
I have information that the bike was restored in the early 90s and that most of the ignition parts were replaced during the fitting of the Alton starter with the power box being unchanged.
 
Digital meters do not like measuring voltage as the emf affects the meter, you need an analogue meter. What makes you think the battery is not being charged, there is no smoking gun in the info you have given.
 
Easiest way to check the alternator is working is Rev the bike with headlights on. Doesnt give you figures but if the light brightens at least you know it’s working.
Used to work with indicators but with my Alton they are normal speed at tick over. Ignition light goes off as soon as motor turns.
 
@Nortoncommandoneil great progress with the checks.

So the battery is good, that’s one thing we can tick off the list.

Your wiring is probably ok as the bike starts and stops, and you have not reported stuttering or back firing.

It sounds like you are getting some charge rather than nothing, since you are seeing charge voltage going above the resting rate of the battery.
So that would suggest that the wires to the alternator stator haven’t been compromised.
We can also assume at this point that the rotor is good, as it’s a new Alton that hasn’t been on there for long (the original Lucas rotors lose magnetism after 40 years which gives you a weak output, but that’s not your issue)


You say you have a Boyer Bransden Power Box - so the original rectifier and regulator have been decommissioned.
Check that the Brown/Blue that used to go to the Zener on the z-plate is properly taped off.
Since this Power Box unit is not compatible with the original ‘silver can‘ 3AW assimilator, double check between the coils that it is not there and that the White/Brown and Green/Yellow that usually feed it are safely taped off.
Ignition light


If everything is looking okay with the above checks, we can move on to checking your alternator output.
Easiest way to do this is to put a headlight bulb across the two AC output wires— the two that usually connect to the yellow wires of your Boyer Bransden Power Box.
This is a simple check, and you are not relying on a multimeter getting interference and dodgy readings.
At idle, you should see a healthy glow from your light bulb.
Ignition light

If everything passes, you are down to the final element - checking the Boyer Bransden Power Box itself.
You can do this with your multimeter, and the engine off, so no worries about bad readings or interference.
There is a guide to testing your reg/rec here on my site - worth printing off the PDF, and writing in the values as you go:
Just take your time, and work through the checks - it will only take you a few minutes to complete.


Shout if you are struggling or get stuck with anything.
 
I also have not been completely impressed with the output of my Alton ES alternator. On a two-day overnight ride, I noticed that my battery voltage was decaying slowly, like the charging system was not keeping up. I noticed that my BSM was also starting to take on an orange/yellow tinge, not the pure green that I have been used too.

When I first installed the Alton, the alternator would charge 13.75 volts at speed with the headlight on. It was struggling to hit 12 volts after the trip.

I have since installed a permanent voltmeter to my bike, in addition to my BSM. I noticed that the charging voltage at high idle was not impressive, so I have gone about trouble shooting the entire system, including pulling the primary cover. I noticed that some of the clearance between the rotor and stator had closed up in a few spots. Also, there was a bit of fine swarf (likely from the clutch) collected by the rotor magnet. I cleaned everything with brake cleaner, and serviced the clutch while I was in there. I reset the stator position, and verified clearance with 0.010" feeler gauge. All screws loctited with Loctite 222.

I went for a 200 mile ride after performing this service, monitoring the voltmeter all the way. The system is charging, but it is not overly enthusiastic about it. When I left home, it was hitting about 13.5 volts at 4000 ish RPM. By the time I retuned home, it was struggling to hit 12.7 volts.

I have a cheapy Amazon reg/rect fitted, and I temporarily fitted my Sparx 3-phase reg/rect (on single phase) to see it would change the values - no appreciable difference. After reading the works of Grant Tiller, I have ordered a moffset-style regulator to see if that will have an affect.

I really can't shed to much in the way of electrical consumers - I have no incandescent bulbs left, my LED headlight is only 30W peak.

Anyone else finding the same thing?
 
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