Is the CS dual saddle different from the S saddle?

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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Is the CS dual saddle different from the S saddle?

Postby rcousine » Thu Sep 14, 2017 5:08 pm

So...I'm trying to fix up a saddle, one of many things this 1958 AJS 18 CS needs.

The saddle I have was...heavily modified, apparently to move it up and back (!), presumably for the needs of dirt-biking.

The old seat is odd enough that I'm considering buying a new seat and being done with it. But...

AMOC lists part 022375 , the heavyweight seat for singles and twins, 1956-1960. No dimensions included.
Feked lists a 1957-60 AJS seat (ajsst38-14), but mentions only the 18S, not the 18CS. They also helpfully show the c-c distance from the front mounts to the rear: 14-1/2".

My bike is not 14-1/2" from front mount to rear. It's more like 14" (I can't remember the exact number, I can re-measure it tonight, but it was far enough off that the saddle wouldn't fit for sure).

So what's up? Do I need a special seat? Is it available? does anyone have a photo or dimensions or diagrams of the stock 18CS dual saddle mount? I can reconstruct my current seat pan if need be...

Ryan Cousineau
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1958 AJS 18 CS (a work in regress)
Ongoing rebuild photos: https://www.icloud.com/sharedalbum/#B16GWZuqDGvT59n

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Re: Is the CS dual saddle different from the S saddle?

Postby ajscomboman » Thu Sep 14, 2017 5:53 pm

You'd be better of biting the bullet and ordering a new seat that's almost certainly going to fit directly from R K Leighton in the UK. I've had 4 so far ranging from 1956 up to 1966 and they all have subtle differences for each year and everyone has fitted.

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Re: Is the CS dual saddle different from the S saddle?

Postby Rob Harknett » Thu Sep 14, 2017 6:09 pm

Saddles are usually found to be of a universal size to fit many marques. Brackets and springs part of the bike marque, made to fit a standard size saddle. Fitting points would also be of standard dimensions. Seat pan sizes of standard sizes for auto cycles, small medium and large motor cycles. I believe seeing what may be a small pan saddle for sports machines like trails etc.
Ashampoo_Snap_2017.09.14_19h07m40s_001_.png

Note this small pan 1958 compt saddle referred to as water proof saddle.
I would have thought, the saddle would be of standard size and fitting points. Spring length and front bracket to suit the marque, which could get altered to suit the rider.
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Re: Is the CS dual saddle different from the S saddle?

Postby rcousine » Tue Sep 26, 2017 4:19 pm

Thanks for the notes, all! This is a dual saddle (for rider and passenger) fitted to a CS. I have reasons to use a custom seat-cover, and given the other issues, I think we'll re-use the pan I have, and maybe get foam from RK Leighton.
1958 AJS 18 CS (a work in regress)
Ongoing rebuild photos: https://www.icloud.com/sharedalbum/#B16GWZuqDGvT59n

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Re: Is the CS dual saddle different from the S saddle?

Postby raffles » Tue Sep 26, 2017 6:19 pm

The seat pan you have is totally wrong for any AMC and so will never fit correctly, nor will anything purchased from lieghtons fit your seat pan
the rear fitting bolts for a cs go up through the rear mudgard to screw into the seat pan. you also have the wrong rear mudgard stay. the correct one is needed to
set the seat hieght correctly.
Tony

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Re: Is the CS dual saddle different from the S saddle?

Postby rcousine » Wed Sep 27, 2017 3:32 pm

raffles wrote:The seat pan you have is totally wrong for any AMC and so will never fit correctly, nor will anything purchased from lieghtons fit your seat pan
the rear fitting bolts for a cs go up through the rear mudgard to screw into the seat pan. you also have the wrong rear mudgard stay. the correct one is needed to
set the seat hieght correctly.
Tony


That makes sense, I know the mudguards aren't stock: they were purchased in the 1960s. I'm likely to replace them, but probably not with an eye to returning to stock.

Regarding the rear fitting bolts for the seat, the ones on my bike do shared duty as the top bolt for the shock. It appears that's how it works on the photos of other CSes I have seen.
1958 AJS 18 CS (a work in regress)
Ongoing rebuild photos: https://www.icloud.com/sharedalbum/#B16GWZuqDGvT59n

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Posts: 218
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Re: Is the CS dual saddle different from the S saddle?

Postby raffles » Wed Sep 27, 2017 5:52 pm

The fixing bolts for the rear of the seat go up trough the mudgard into the seat pan (underneath where the seat sits on the mudgard)
Tony

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