G12 drive chain size

Information relating to the Matchless G12 or AJS Model 31 650cc twin
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willowbedone
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Location: east sussex

G12 drive chain size

Post by willowbedone »

Could someone tell me the correct drive chain for a 1960 g12 Is it 5/8 X 3/8
Thanks Ian
SPRIDDLER
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Re: G12 drive chain size

Post by SPRIDDLER »

If it's any help it says 68 links of 1/2" x 0.305" under 'Chains' on page 30 of the spares list here:

http://archives.jampot.dk/book/Spares_l ... G12CSR.pdf
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Groily
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Re: G12 drive chain size

Post by Groily »

Primary or rear Spriddler?
Rear is your 5/8 x 3/8, same as most other Brits over about 250cc bar the odd older Norton with narrower.
Number of links on both chains depends on sprockets used on crank and 'box. 98 would be most likely for final drive I think, a lot of primaries end up as an odd number, some were from Day One.
SPRIDDLER
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Re: G12 drive chain size

Post by SPRIDDLER »

Groily wrote: Fri Mar 31, 2023 6:18 am Primary or rear Spriddler?
Whoops! I read the wrong line.
(I must be getting too old for all this :( )

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Groily
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Re: G12 drive chain size

Post by Groily »

We're all getting too old compared to back when or then Neville! So much better than the alternative though . . .

Funny how many odd-link lengths AMC used.
I try to keep half links out of things, but couldn't on the primary on the M31, which runs a 21 tooth on the crank. (My only other choice from my box of bits here was a 24 - far too big with the 19 I have on the 'box rather than the 'book' 16 or 17).
So I think without going and checking that I'm on 67 and 98. Maybe 5% geared up compared to the standard 23-42-16(or 17CSR)-42.
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