AJS 31 battery charging issues

Information relating to the Matchless G12 or AJS Model 31 650cc twin
User avatar
Duncan
Member
Posts: 2118
Joined: Thu Jul 10, 2003 1:00 am
Location: HAMPSHIRE UK

Re: AJS 31 battery charging issues

Post by Duncan »

Mick
Yours has been locked by the three centre pop marks you can see in the photo.
These are to retain the breather disc and should not be removed
Rangy65
Member
Posts: 434
Joined: Tue May 07, 2013 11:35 pm
Location: LINCOLNSHIRE UK

Re: AJS 31 battery charging issues

Post by Rangy65 »

I think your problem may be with the Stator & Rotor. I have fitted a high output lucas RM23 unit to my 61 G3 and was suprised when it did not produce sufficent charging.

After speaking with Wassell's i discovered the issue is the original rotor is 70mm in diameter and when fitted with an RM23 the airgap/distance between rotor and stator is to great.

The fix was to fit a new lucas rotor of 74mm diameter. This may be the case with your bike.

Hope this helps.

Steve
Geoff Sharpe
Member
Posts: 13
Joined: Thu Mar 31, 2016 12:16 pm
Location: SURREY UK

Re: AJS 31 battery charging issues

Post by Geoff Sharpe »

JohnHewes wrote:I would think that if you have 15v at the Boyer out feed then the alternator and Boyer are working OK. For some reason this is not reaching your battery and that is where you have to find the fault.
All your current negative measurements prove is that the amp meter is connected the right way round.
You need to check against the wiring diagram for an alternator bike, substituting your Boyer output for the rectifier output.
It will be a balls aching job! Get the tank off and the headlamp reflector off and try tracing the wires and comparing them with the diagram, not easy but I feel sure that is where your problem lies.
My G3 has a by similar arrangement and it works really well, very pleased with it, but it also took some sorting out at first, traced to a bad connection I had made in the headlight.
Good luck! John
Hi John, thanks for your advice a good few weeks, or months , ago. I finally resolved my charging problem this evening. Congratulations, you and Albert (aobp11) came closest to predicting the cause and pushed me towards identifying the actual fault. It was down to a broken wire coming from the ignition switch in the headlamp. I repaired it with a bullet connector and was delighted to see the ammeter registering positive amps with the engine running for the first time ever under my ownership. A eureka moment and a beer to celebrate. Happy days.
Thanks again to all for all the help and advice.
Geoff


Sent from my iPhone using Tapatalk
Locked