G9 Help for a newbie

Information relating to the Matchless G9 or AJS Model 20 500cc twin
Chris B_LAPSED
Posts: 45
Joined: Mon Dec 28, 2020 8:31 am
Location: Nottinghamshire

G9 Help for a newbie

Post by Chris B_LAPSED »

Hi there firstly this is my first forum post and I would like some advise please. Sorry if its been covered lots before.


So I went to view a 1953 Matchless G9 yesterday that I was dead set on having. She fired up lovely and sounded sweet. Sadly when coming to check the electrics. Lights/horn there was nothing. (Still running 6v) A recent new battery had been fitted and the owner said she had been charging nice up until today. These things happen. So the owner is going to sort the problem out before I purchase. Just wondered if anyone could shed any light?

Also the bike has had the de compressor removed over the mist of times. However she starts 1st/2nd kick from cold so not a problem but I noticed that to turn the bike off he was stalling her. Just wondered what the best way would be to maybe add a cut off switch?

Many thanks in advance
Beefheart
Member
Posts: 64
Joined: Mon Oct 17, 2011 9:34 pm
Location: Bedfordshire UK

Re: G9 Help for a newbie

Post by Beefheart »

Suspect the regulator, as recommended by most correspondents on the forum replace it with a dvr2. Not aware of decompressor fitted to twins there certainly has never been one on my 53 G9.
Greybeard
Member
Posts: 456
Joined: Mon Jun 29, 2015 8:49 pm
Location: East Yorkshire

Re: G9 Help for a newbie

Post by Greybeard »

Hello, Chris.
If this is going to be your first venture into classic motorcycling I would suggest that your first steps should be to read everything you can about the type of bike youre looking for and make a list of all the known/regular issues. Only if youre happy you can tackle any repair jobs yourself, and there will be many (or are content to pay - often heavily - for it to be done) then take the plunge. Dead electrics could be due to many things - the phrase 'it was charging nicely yesterday' ranks alongside the phrase 'they all do that' in the sellers phrase book of bull**** ;)
There is no decompressor on a twin and for 1953 the ignition cut-out was a button on the points cap of the mag. A remote kill button can be fitted.

Godd luck and tread carefully. Steve
Chris B_LAPSED
Posts: 45
Joined: Mon Dec 28, 2020 8:31 am
Location: Nottinghamshire

Re: G9 Help for a newbie

Post by Chris B_LAPSED »

Thankyou for your replys. Iv been doing as much research as possible with a long way to go and any info would be greatly appreciated...having previously owned a lovely G3 that I had zero issues with I regrettably sold her but decided I would like another matchless and came across a nice G9. I didn't have a reason not to believe the seller in regards to the charging as he was genuinely shocked and very apologetic. He said he would sort the issue before I purchase her. So iv learned that the G9 doesn't have a de compressor lol. I will look into having a kill button fitted for convenience. Thanks again
User avatar
clive
Member
Posts: 5657
Joined: Mon Jan 01, 1990 12:00 am
Location: LONDON UK

Re: G9 Help for a newbie

Post by clive »

Certainly sounds unusual for a bike to be charging nicely and then, with a new battery, no lights or horn. The charging system should not prevent the lights and horn working, especially as the horn should be wired directly to the battery. I suppose the regulator could have failed to disconnect and flattened the battery by discharging through the field coil. So if the owner is going to sort it then all well but fitting an electronic regulator is a good idea anyway. It is worth joining the club as there are years of experience available here. Guest membership only lasts 3 months and you only have limited access to the site. Good luck with your purchase the 500 twin is a very nice bike.
clive
if it ain't broke don't fix
bitza
Member
Posts: 452
Joined: Tue May 27, 2003 1:00 am
Location: SHROPSHIRE UK

Re: G9 Help for a newbie

Post by bitza »

I restored a 53 g9 there is no decompresser fitted,if your bike still as the original magneto the engine kill button is on the end cover you should see it easily, with the engine running press the button and the engine should stop. Also a D VR 2 regulator would be a good mod a easy job to swap.
And has been stated with the engine running the horn should operate,
Mick D
Posts: 2886
Joined: Mon Mar 24, 2014 5:44 pm
Location: Aberdeenshire

Re: G9 Help for a newbie

Post by Mick D »

Hi and welcome

The electrical fault could be a fuse in the battery supply line, (a common non standard modification), that, or a break in the supply line are the only singular, (likely), faults I can think of that will knock out both horn and lights at once.

Let the seller sort it but quiz him on the rectification before buying.

Regards Mick
Chris B_LAPSED
Posts: 45
Joined: Mon Dec 28, 2020 8:31 am
Location: Nottinghamshire

Re: G9 Help for a newbie

Post by Chris B_LAPSED »

Thanks for all your replys. I will keep you posted once iv heard back of the cause of the problem. If anyone has any other advice to look out for any input would be greatly appreciated. Cheers
g80csp11
Member
Posts: 1567
Joined: Mon Jan 01, 1990 12:00 am
Location: WEST SUSSEX UK

Re: G9 Help for a newbie

Post by g80csp11 »

what about battery being being refitted the wrong way around , system will reverse charge and flatten in minutes
g5wqian
Member
Posts: 220
Joined: Wed Nov 18, 2015 7:43 am
Location: wiltshire
Location: near swindon wilts

Re: G9 Help for a newbie

Post by g5wqian »

hi chris;
to start the g9 you just need to retard the advance lever a bit and then kick it over , full advance is with lever closed and for starting you open it so you have about 1/4" of cable showing in the exposed lever slot .

check if someone has fitted a fuse in the battery cable but also check the wires are not trapped behind the battery and have rubbed against the battery tray and exposed the wire to the metalwork .
i had bit of problem with my ajs mod30 and found i had such a problem .

charging usually starts when the engine speed is above idle , so you need it about 1100rpm and upwards before you may see ammeter movement .

check batt voltage with an analogue voltmeter when engine is running and when stopped , just in case its the ammeter .

check electrolyte level in battery hasnt dried up .

my engine just has stop button on magneto cover , works fine and easy .

be carefull to keep eye on mouth of carb when starting if getting a backfire or chuff out of it , especially in summer as it may end up with a flame coming out that you wont notice and then set alight .

i use a short gauze bellmouth which greatly reduces chance of any flames appearing out the rear of carb mouth and heading upwards towards tank .

the engine will have a little whine to it when idling , something like youd hear from a supercharger , this is normal coming from the timing gears and dynamo drive etc .

usually they run ok on full advance when out riding about but if you hear it pinking , especially uphill , just reduce the advance lever a little .
i use esso supreme fuel but do find sometimes i get a bit of pinking on the pistons when engine is pulling hard so i have tendency to just put a little retard in and its all fine then .

hope you enjoy the bike , i love mine and would ride it anywhere .

cheers
ian
Locked