AJS & Matchless Owners Club

I have one bike left to get running correctly, renewed plug and ht lead as it wouldn't start, it now runs and starts well, but whilst running the bike misses every 4 - 5 seconds.
1959 Matchless G3 ls 350 coil ignition alternator I,m guessing ignition?.

Hi

Does it miss at various throttle settings / under acceleration / decelerating / cruising?

Does it miss at various revs or just a narrow band?

Answers to the above will narrow things down a bit - it could be fuel related, partially blocked jet - incorrect mixture.

If you're happy that the timing is good, the wiring is good and it's not a fuelling issue I'd replace the capacitor as a first step.

Regards Mick

Thanks Mick,
Cleaned jets, replaced capacitor, big improvement especially full throttle, rode the bike problem free for about 60miles, pressed horn a couple times and noticed bike pulling back with a bit of misfire each time horn pressed.
Then 5 miles later bike died, wouldn't start on EMG, and had to be rescued by AA.
Recharged battery on return and bike started again.
Thinks I need to replace alternator.
Will do tests on rotor and alternator output first
1959Matchless G3. 350cc.

Hi Mike

I'd look to the rectifier in addition to the alternator if I were you - why not check the supply to the battery first, then the supply to the rectifier.

Regards Mick

mikeydpippin wrote:Thanks Mick,
Cleaned jets, replaced capacitor, big improvement especially full throttle, rode the bike problem free for about 60miles, pressed horn a couple times and noticed bike pulling back with a bit of misfire each time horn pressed.
Then 5 miles later bike died, wouldn't start on EMG, and had to be rescued by AA.
Recharged battery on return and bike started again.
Thinks I need to replace alternator.
Will do tests on rotor and alternator output first
1959Matchless G3. 350cc.

Was that your bike I saw on Priorswood road on an AA trailer ?

Yes Alan, that was me,

Hi

Forgot to ask - what was your ammeter indicating when running at around 50mph?

Did you have your headlight switched on, (are you running standard filaments or LEDs)?

Regards Mick

Ammeter was showing no charge but slight discharge, no lights were on.
I have connected multimeter to battery terminals and with slight revs the amperage stayed at approx 6v.
I have connected alternator (3 wires) wires together as separate pairs with a light bulb, bulb lights when 2 green and yellow wires are joined but doesn't light when any other wires joined.
and no continuity when wires earthed, suggesting no earth leak.

Could be worth checking voltage on the output side of the ammeter. When first checked on my ‘60 G3 it was less than 4 volts! Engine ran fine until indicators were used, then it would miss fire in time with the flashes.

Changed ammeter and all was fine.

Hi

There's a good table on page 89 of the workshop manual detailing what you should expect from the alternator outputs but essentially the bulb ought to light when it bridges the green/white - green yellow and light less brightly when bridging the green/black - green/yellow.

Regards Mick