G12 Tank puzzle

Information relating to the Matchless G12 or AJS Model 31 650cc twin
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Mondrian3
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Joined: Tue Jul 22, 2014 4:41 am
Location: NY USA

G12 Tank puzzle

Post by Mondrian3 »

Hello all,

I'm working on getting my 1960 G12 up and running - a long, hopefully fun project.

Before I strip the tank and repaint I thought to ask you if this a proper G12 petrol tank? How could I identify it as an OEM tank or something else - maybe competition or CSR? Maybe from India? Can't seem to find photos or diagrams of one with all the same characteristics. Large badges with knee indents - it has no reserve side and came with no tap at all, just a nozzle with fuel tube leading to the carb.

cheers,
Jon
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-Jon
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Duncan
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Location: HAMPSHIRE UK

Re: G12 Tank puzzle

Post by Duncan »

Mondrian3
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Joined: Tue Jul 22, 2014 4:41 am
Location: NY USA

Re: G12 Tank puzzle

Post by Mondrian3 »

Thank you Duncan! I think you're spot on!

The tank seems to fit the bike well enough. I need to do a bit more research but maybe a fuel tap in place of the spigot will work.

My wife sends you extra thanks as she thinks your answer will reduce my puzzled muttering around the house. We'll see.

cheers,
Jon
-Jon
SPRIDDLER
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Location: WEST SUSSEX UK

Re: G12 Tank puzzle

Post by SPRIDDLER »

Many pics of G12's in the Photo section here which may help:

http://www.jampot.com/pic_search.asp?se ... rch&num=10
'There is a tide in the affairs of men
Which taken at the flood............'
Mondrian3
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Posts: 6
Joined: Tue Jul 22, 2014 4:41 am
Location: NY USA

Re: G12 Tank puzzle

Post by Mondrian3 »

Thank you Neville. That clears it up. Great resource photos. Since it was pointed out, I'm embarrassed to say I'm seeing the tank everywhere. I kept looking at 1960 and earlier.

Next I need to figure out if I have the wrong front mudguard, or the wrong fork sliders. The fender has holes for stays on the front, but no forward holes on the sliders.
-Jon
Reynard24
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Location: CAMBRIDGESHIRE UK

Re: G12 Tank puzzle

Post by Reynard24 »

Hi Jon
Those ‘63 on tanks should use a 1/4”BSP thread petrol tap not the 1/8” BSP of the earlier tanks. 1/4”BSP has an external diameter of just over 1/2”. I've found that the best taps are BAP type as fitted to Triumph and Norton, other types are available but most suffer when used with ethanol laced fuel and I think you have a higher concentration of it in the petrol over there.
Only the CS & CSR fork sliders had twin lugs for the mudguard (fender) stays so your bike probably started out with heavier valenced mudguards and has been fitted with a pattern front guard to give it a CSR look, your rear guard and lamp housing are also wrong but you have a good base to start from and I think those tanks with the zig zag lining and knee-knocker badges look so much better than the staid item it should have.
Hope you get it sorted.
Mondrian3
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Posts: 6
Joined: Tue Jul 22, 2014 4:41 am
Location: NY USA

Re: G12 Tank puzzle

Post by Mondrian3 »

Thank you Reynard! That solves several mysteries for me. Very difficult to find the deeper mudguards over here but now I know what to look for. A 1/4" BSP tap should be easier to acquire. Thank you for the heads up. Luckily I do have access to non-ethanol fuel over here - in the Northeast a shop called Stewarts carries it at all their stations. I use that in my small engines.

I've been wanting a Matchless for a long while. I'm really happy to be working on it.
cheers!

Jon
-Jon
Mondrian3
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Posts: 6
Joined: Tue Jul 22, 2014 4:41 am
Location: NY USA

Re: G12 Tank puzzle

Post by Mondrian3 »

New Question- I'm looking around for some proper mudguards for my fine steed and it's nigh impossible. I've seen one AJS/Matchless set over the past year auctioned at ... well let's say a surprisingly high price.

Wondering now, would a set of fenders from a Norton ES2 or some other bike work with a minimum of finagling or look appropriate on a 1960 G12?
-Jon
mdt-son
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Location: Vestland NORWAY

Re: G12 Tank puzzle

Post by mdt-son »

Hello

1960 G12 (STD) mudguards were also used on G3/G80 models. I don't know if this helps though. They will be rare no matter what bike they were fitted on. My best advice is to look for them in the UK: Having them shipped to the US can't cost an arm and a leg? Talk to Steven at AMC Classic Spares.
Sometimes all you can get hold of are rusty samples. In this case, making a fiberglass replica is a cheap solution. This should work for the front end. I am less convinced a fiberglass mudguard will last at the rear, but worth a try (it can be reinforced by steel inlets). They will not rust!!

Before making inquires over the pond, I would make a call to Baxter Cycle (Iowa) and the AMOC N-A section.

Good luck!

-Knut
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