1964 G80CS??

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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bluestone
Posts: 2
Joined: Tue Jan 16, 2007 6:40 pm
Location: FINLAND

1964 G80CS??

Post by bluestone »

Hello from Finland!

Last summer friend of mine traded his Yamaha XT600 enduro to 1964 Matchless.
Papers says it´s a 350cc model but it´s 500cc, but he´s not sure the year.
There´s following numbers on the bike: engine G80CS-4670, gearbox MA4964C (1 to 3 gears are very close, but 4 is high; is this for trial?), frame has number (on right leg just below fuel tank) 10840, carb AMAL389B32 and it has Lucas Competition Magneto.
Exhaust is routed low, parallel to bottom of the frame. I´ve seen photos of G80CS which has exhaust routed higher.

We are looking for any technical information of this bike; engine specs, is it rare...anything.
Bike is in driving condition, but electrics doesn´t work properly.
Thanks!!
Bluestone
Don Madden
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Posts: 2882
Joined: Mon Jan 01, 1990 12:00 am
Location: USA USA

1964 G80CS??

Post by Don Madden »

The numbers are consistant with 1964 competition bikes. The G80CS prefix on the engine indicates a scrambler & the frame no. should be preceded with a C, (C10840).

The C in the gearbox no. indicates a trials gearbox, supported by the 3 close ratios with a gap to top.

1964 G80CS scramblers could only be fitted with high pipes, as the space between the bulge in the crankcase & the competition footrest was to close for a low pipe. Switching the footrests to touring type would allow the fitment of a touring down-pipe.

You seem to have a mix of parts. Does the oil feed to the top end come out of the front of the plunger pump, (pre-1964), or at the rear of the gear type case, 1964-up)?

Does the frame have scrambler footrests fitting over the bottom rails on a round rod or angled ones attached to the outside of the frame fixed to a square rod?

Is the oil tank a pannier type on the left, (scrambler), or a squarish one on the right, (trials)?

The answers will help clarify the model.

The Club dating officer is the only official source of the exact data on the configuration when dispatched.

Any competition type AMC is highly valued.

Cheers, Don.
bluestone
Posts: 2
Joined: Tue Jan 16, 2007 6:40 pm
Location: FINLAND

1964 G80CS??

Post by bluestone »

Thanks Don!

I must check that frame number again and verify those footrest and oil tank specs.
Owner told me that this bike has been competition use when new and then been in storage dissasembled to pieces until mid-80:s when it´s been registered to road use.
Bluestone
torker
Posts: 21
Joined: Wed Mar 02, 2011 12:00 am
Location: USA

1964 G80CS??

Post by torker »

Bluestone, I am trying to find information on my 1964 G80CS. Your engine #G80CS-4670 mine is #G80CS-4660. My engine has the plunger type oil pump, low pipe, fold up pegs, left side oil tank. I am checking to see if your motor has the plunger (1963) or the gear (1964) type oil pump. I am trying to find out if some early 1964 C80CS had leftover 1963 motors installed from the factory.

Tim
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Malleon
Posts: 1329
Joined: Sun Jan 01, 1995 12:00 am
Location: WREXHAM UK

1964 G80CS??

Post by Malleon »

Even if the machine was despatched from the factory with an engine fitted with the Norton type pump, the engine could have been replaced at some time in its history. Your best source of reliable information is already given by Don's advice, so either take it or leave it !
torker
Posts: 21
Joined: Wed Mar 02, 2011 12:00 am
Location: USA

Re: 1964 G80CS??

Post by torker »

Malleon, The dating information does not state if the motor had a "plunger" or "gear" type oil pump. So there is no way of knowing if some early 1964 G80CS were shipped with "plunger" type oil pump engines. Here is another 1964 with the "plunger" type engine: http://www.bonhams.com/auctions/19679/lot/260/ The engine number is stamped in the 1964 and later format like mine. So is their any proof that "all "1964 G80CS came with the "gear" type oil pump motors?

These engine numbers all seem to have "plunger" type oil pumps (G80CS4583.... G80CS4664 (my engine).... G80CS4673.... G80CS4683) all are stamped in the 1964 and later format without the year prefix. The earliest "gear" type oil pump engine number I have found is G80CS4688.

Maybe I'm barking up the wrong tree, but I find this very interesting. Tim
mdt-son
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Posts: 373
Joined: Wed Feb 01, 2012 1:22 pm
Location: Vestland NORWAY

Re: 1964 G80CS??

Post by mdt-son »

Even though the stamping is similar to the 1964 format doesn't mean the bike was built for the 1964 season.
If the engine is of the plunger type and numbers match (and no trace of overstamping), the bike was probably built in Q1-2 of 1963.
The new model year began in Sept. 1963 after the works holidays. During the holidays all jigs and tooling had to be altered for the new models.
Also, all the necessary parts had to be on hand for the assembly line to run smoothly. For instance, the oil lines for the 1964 engine differs from the 1963 model.
Therefore it seems very unlikely that AMC would bother assembling a bike in the new model year which deviated from the specs in effect.

Going by the close numbers, (4664 ....4688), I guess your bike was assembled shortly before the works holidays, maybe put into storage and shipped after the holidays.
Arriving in the US, Berliner probably wanted to get rid of a non-current model and labelled it as a 1964 model.

A conscious buyer wanting the latest model would certainly not accept a bike with a non-current engine? After all, the revised engine was hailed by the PR-department of AMC. Then as now, new models are important to bolster sales, which AMC desperately needed at this point in time. Alongside the revised engine came a revised G12 engine as well ..... and new cycle parts. It must have been a very busy year for all the departments.

Knut
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