Missing

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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Missing

Postby mikeydpippin » Sat Jul 28, 2018 7:38 pm

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?.
Mike

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Re: Missing

Postby Mick D » Sat Jul 28, 2018 8:51 pm

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

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Re: Missing

Postby mikeydpippin » Tue Jul 31, 2018 4:43 pm

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.
Mike

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Re: Missing

Postby Mick D » Tue Jul 31, 2018 6:36 pm

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

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Re: Missing

Postby Harry44 » Tue Jul 31, 2018 8:21 pm

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 ?
si is does non opportunus vos postulo a maior pango

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Re: Missing

Postby mikeydpippin » Tue Jul 31, 2018 8:29 pm

Yes Alan, that was me, :oops: :headbang:
Mike

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Re: Missing

Postby Mick D » Wed Aug 01, 2018 6:29 am

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

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Re: Missing

Postby mikeydpippin » Wed Aug 01, 2018 11:15 am

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.
Mike

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Re: Missing

Postby Expat » Wed Aug 01, 2018 1:50 pm

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. :o

Changed ammeter and all was fine. :D
Keep shiny side up.

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Re: Missing

Postby Mick D » Wed Aug 01, 2018 3:22 pm

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

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