1964 G12 CSR siamesed downpipes

Information relating to the Matchless G12 or AJS Model 31 650cc twin
tony54
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1964 G12 CSR siamesed downpipes

Post by tony54 »

Hi all. I have what I take to be Armours pipes fitted at present. The fit is appalling and whoever did fit them has cut the tail too short so barely 1/2" inserts into the silencer, so I have decided to get a set made.
My question to you knowledgeable fellows is how close to the original design are the Armours pipes and, if noticeably different, has anyone got an original picture please.
Many thanks
Andy G
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Re: 1964 G12 CSR siamesed downpipes

Post by Andy G »

If it's of any interest I bought an Armors system (stainless version) just a couple years ago for a 62 31csr and it fits perfectly. Can you adjust the silencer mount to bring forward?
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ajscomboman
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Re: 1964 G12 CSR siamesed downpipes

Post by ajscomboman »

Andy G wrote: Thu Dec 29, 2022 6:37 pm If it's of any interest I bought an Armors system (stainless version) just a couple years ago for a 62 31csr and it fits perfectly. Can you adjust the silencer mount to bring forward?
But did the short pipe go in the correct way? Armours are notorious for setting the bend on the short pipe wrong meaning the only way it'll fit is with the short leg in the head causing the pipe to come out at a forward angle to clear the down tubes. The correct orientation is for the long leg to come out of the head past the down tubes before then sweeping across at an angle to meet the Y branch. A picture would be handy
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Re: 1964 G12 CSR siamesed downpipes

Post by Andy G »

Hmmm, now that's a question..I'll have to take another look, but what effect does it have to reverse the pipe?
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Les Howard
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Re: 1964 G12 CSR siamesed downpipes

Post by Les Howard »

It's very sad indeed but Armours exhaust pipes are often the wrong shape nowadays. My Norton ones are quite wrong in terms of overall shape and the angle was wrong which needed the top location ring hammering to change the sealing angle. I say it is sad because it's about the only company that makes exhaust pipes now ...isn't it?
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clive
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Re: 1964 G12 CSR siamesed downpipes

Post by clive »

Feked have many pages of AJS and Matchless exhaust pies and silencers on their website. About 10 years ago I lent them my 58G11cs and an original set of pipes over winter. They used it to manufacture a pattern for the siamese pipe which goes over the comp footrest. Eventually i got a complimentary pipe set. With a little tweaking (less tweaking than the armours version which i had previously had fitted) they fitted well and had the correct arm to fit the frame bolt on the small pipe. The armours version had a stud on the small pipe and was bent to go up and over the footrest. Unnecessary, made it harder to fit and not the same as my original pipes. 10 years later the chrome on the Feked pipes is still pretty good and the bike is used in the wet. I think even from the factory the pipes may have needed a tweak.
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Re: 1964 G12 CSR siamesed downpipes

Post by Groily »

I put Feked's siamesed standard 'under the footrest' version on my M31 10 years ago nearly and it fitted OK. Chrome still OK too, like Clive's, despite all weather use and a good few miles. But not a C version, so can only comment on 'finish', not fit.
Armour's siamesed ones on my 500 have always been OK, an easy fit (and quite long-lasting), but again, simple compared to C versions.
(Dunno who made the pipes on my 650SS Notrun as haven't replaced in my ownership - they're not originals but are also an easy fit, as are the Campbell silencers.)
I'm FAR too young to have played with or tweaked original factory bits I think, even if I've had my 500 in continuous use since the mid-70s!
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ajscomboman
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Re: 1964 G12 CSR siamesed downpipes

Post by ajscomboman »

Andy G wrote: Fri Dec 30, 2022 10:59 pm Hmmm, now that's a question..I'll have to take another look, but what effect does it have to reverse the pipe?
Only that it looks wrong if you know what you're looking at! Loads of CSR's have them fitted upside down as 9 times out of 10 it's the only way they'll fit. I got a set from Gordon at Feked when they first started to make them for my 63CSR and they fitted 100% spot on and still look great. I bought a bike that had Armours ones on and no way in hell were they ever going to fit the proper way. The pipe long leg was too short and it caused the sweep across to hit the down tubes. Reversed with the short leg in it threw the pipe forward as the bend is shallower and allowed the long leg to clear the down tubes and still fit into the branch.

FYI even Sammy Miller's CSR has them fitted the wrong way!
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Re: 1964 G12 CSR siamesed downpipes

Post by Andy G »

ajscomboman wrote: Fri Dec 30, 2022 3:29 pm the only way it'll fit is with the short leg in the head causing the pipe to come out at a forward angle to clear the down tubes. The correct orientation is for the long leg to come out of the head past the down tubes before then sweeping across at an angle to meet the Y branch. A picture would be handy
This'll be wrong then!
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Les Howard
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Re: 1964 G12 CSR siamesed downpipes

Post by Les Howard »

I've always imagined that FEKED exhaust systems were in fact just selling Armours products. This is nice to know if they are an entirely different manufacturer and with good reports on their quality....probably shop with them next time
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