Model 18CS

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
silverfoxracing
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Location: australia

Model 18CS

Post by silverfoxracing »

Be gentle with me!! just joined the club!. New to the scene!! Just bought my first AJS, Been told it is a 1957 AJS 500 model 18 CS Scrambler. (it has the 18 CS on the engine number although it does have 58 cases. They were replaced in its life. Looking for some info on the bike. I tried the Machine dating part of the site with the frame number but no joy. Anybody able to decode it for me? It is supposedly a bike bike built by Roy East from Australia in the AJS factory when he worked there in 1957. He raced it around England and Europe in 57/58 before bringing it home with him. Frame number +016117 M & B Mean anything to anybody? sorry if this is the wrong place to ask. Cheers
SPRIDDLER
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Re: Model 18CS

Post by SPRIDDLER »

Welcome to the club, Adrian.
There's a fair bit about him via Google including wins with a BSA engined Ajay.
Here's an extract........

Travelling with Fisher, Roy made the trek to Royal Park, Adelaide for the 1959 Australian Scrambles Championship. Aboard a hybrid machine comprising an iron BSA engine in an AJS frame, East defeated Ray Fisher and Charlie West to take out the 350cc title – the first time a NSW rider had won an Australian Scrambles Championship. It was his second national title within 12 months, and in two different disciplines of the sport.

Full biographic article here:

https://www.oldbikemag.com.au/roy-east-great-rounder/

You can find original manuals here under 'Books':

http://archives.jampot.dk/

Can't help with the frame number though but Bacon's Restoration book gives some date ranges.
'There is a tide in the affairs of men
Which taken at the flood............'
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dave16mct
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Re: Model 18CS

Post by dave16mct »

That isn't the frame number. It's a casting number. The frame number will be on the timing side of the headstock next to the sidecar lug. It will probably be 4 numbers and end with a 'C'
Dave
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ajscomboman
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Re: Model 18CS

Post by ajscomboman »

There is very little in the way of frame dating for comp models.
silverfoxracing
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Location: australia

Re: Model 18CS

Post by silverfoxracing »

finally found the correct Frame number under the seat post!! 7924 c. Engine number is 58/18 2792 c. I believe the cases may have been changes at some stage of its life, but also could be pre production cases. A normal B8ES plug is to long for the head and it needs 2 washers under it to stop it from bending the electrode over? any ideas on this?
g80csp11
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Re: Model 18CS

Post by g80csp11 »

its normal to need 2 washers for later heads , i do on mine
silverfoxracing
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Location: australia

Re: Model 18CS

Post by silverfoxracing »

g80csp11 wrote: Fri Jul 08, 2022 12:44 pm its normal to need 2 washers for later heads , i do on mine
by later heads? what years? new to all this!! lol
SPRIDDLER
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Re: Model 18CS

Post by SPRIDDLER »

silverfoxracing wrote: Fri Jul 08, 2022 10:30 am A normal B8ES plug is to long for the head and it needs 2 washers under it to stop it from bending the electrode over? any ideas on this?
Did you see Thrifty Peter's (g80csp11) reply to your same query last Monday in the 'Competition / Racers' forum advising that it's normal to need two plug washers on the CS heads.

Hopefully my earlier reply in this thread with info on Roy East was of some use to you.
Last edited by SPRIDDLER on Fri Jul 08, 2022 7:12 pm, edited 2 times in total.
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Which taken at the flood............'
g80csp11
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Re: Model 18CS

Post by g80csp11 »

my engine is a 61 G80CS , but dont know if head is original I think the way to tell is that if teh spark plug thread is not 14 x 1 mm pitch all they way it will need the spacer . The issue is that the earth electrode is bent when it hits the smaller diameter drilling into the head A double spark plug washer fixes the issue
G15 Roy
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Re: Model 18CS

Post by G15 Roy »

silverfoxracing wrote: Fri Jul 08, 2022 10:30 am finally found the correct Frame number under the seat post!! 7924 c. Engine number is 58/18 2792 c. I believe the cases may have been changes at some stage of its life, but also could be pre production cases. A normal B8ES plug is to long for the head and it needs 2 washers under it to stop it from bending the electrode over? any ideas on this?

You need to post a photo of the frame number as 1958 would not be under the seat you may have a mixture of parts.
Roy
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