G15 Mk2 Swingarm

Information relating to the Matchless G15 or AJS Model 33 750cc twin. This also includes the G15 Mk II and the G15/45
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R+shent
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G15 Mk2 Swingarm

Post by R+shent »

Hi my name is Roy i am a new member.
I purchased a 1964 G15 Mk2 basket case imported from the states about four years ago and have just completed a full nut and bolt rebuild, in fact i started the engine yesterday. When i stripped the bike down i carefully logged the parts and took loads of pictures for reference. I have subsequently purchased a Norton NC15CS and a G15 CSR and have noticed that speedo drive side rear wheel spacer on the bike i have completed is about 12mm longer than the ones on the other two machines. I have checked the rear sprocket and gearbox alignment which looks ok and there is no visible signs of damage to the swingarm.
The measurement between the swingarm fork ends on the two other bikes is 203mm this one is 215mm does any one know if the G15 Mk2 had a different swingarm or could it be off another model.
Thanks
Roy
Reynard24
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Re: G15 Mk2 Swingarm

Post by Reynard24 »

My 1964 Model 18 and 1965 G15Mk2 both have the 203mm gap between the ends of the swingarm but my 1963 G15/45 has the larger 215mm gap. This last bike has the interim hub whereas the others have Norton hubs.
There are also different spacers between the ends of the fork on the speedo side for the 64 and 65 bikes. The gap between the fork ends is wider on the 65 bike although the hole for the Norton spindle is the same on both spacers. I could of course be the victim of a bodging PO but both wheels line up properly and the spacer fits perfectly between the fork ends on both bikes.
I'd therefore suggest you have an early '63 on rear fork which was originally intended for the interim hub and thus the speedo spacer is wider to accommodate the Norton hub - unless anyone has any different explanation?
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ajscomboman
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Re: G15 Mk2 Swingarm

Post by ajscomboman »

As far as I'm aware there a 4-5 different swing arms, candle stick models, jampot models up to 54, then another for 55-62 for all models, then 63 only CSR which is narrower than the tourers but still using the AMC chainguard and full width hub, finally the 63 tourer and 64 CSR's models with Norton hubs and chainguard. I have 4 out of the possible 5 so will measure tomorrow and report back.

I'm excluding P11's from this equation!
mdt-son
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Re: G15 Mk2 Swingarm

Post by mdt-son »

I'd say there are 7 different swinging arms for heavyweight models, excluding the G3C/M16C, G85CS & P11 series.

1. Candle stick and Jampot damper models 1950-1953: #014307
2. Jampot damper models 1954: #021023
3. Jampot damper models 1955-56 and Girling clevis end damper models 1957-62: #021543
4. Jampot damper models 1956-57, CS models only: #022637.
5. Girling non-clevis end dampers for forked support s/a 1962-63, 1963 G12CSR only and 1962-68 G80CS: #028059.
6. Girling non-clevis end dampers and single side support for 1963 roadsters (excl. G12CSR), which also featured the interim rear hub: #029063
7. Girling non-clevis end dampers and single side support for 1964 roadsters incl. G15 series, which all featured the Norton rear hub: #030001.

-Knut

*Revised 2021-01-05
Last edited by mdt-son on Tue Jan 05, 2021 12:36 pm, edited 1 time in total.
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ajscomboman
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Re: G15 Mk2 Swingarm

Post by ajscomboman »

Jampot models changed in 55 and the swing arm can be used for both types of suspension till 62-63 depending on model. So that makes 5 types
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ajscomboman
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Re: G15 Mk2 Swingarm

Post by ajscomboman »

Sorry got side tracked today, I'll sort out the sizes in the morning.
R+shent
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Re: G15 Mk2 Swingarm

Post by R+shent »

Thank you all for your comments, I have refitted it with the same dimension spacers that were fitted when it arrived and everything looks ok so i will give it a run when the weather improves and check the chain alignment again.
Thanks again
Roy
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