Competition Jampots?

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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Pharisee
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Competition Jampots?

Post by Pharisee »

I've just started to rebuild the leaking Jampot rear suspension units on my '56 G80CS. Having got them apart, I've just noticed that the bottom clevis casting has the letter "C" stamped into it. It could be coincidence but were there any differences between the Jampots fitted to competition machines and the touring models?
John
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dave16mct
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Re: Competition Jampots?

Post by dave16mct »

The damper valve, buffer spring and main springs are different. If you look at the parts list it's all in there.
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Re: Competition Jampots?

Post by Pharisee »

dave16mct wrote:The damper valve, buffer spring and main springs are different. If you look at the parts list it's all in there.
Dave.
Yes, Dave.... I thought about that a few minutes after I posted. There would seem to be a lot of parts that are different. Fortunately, the units I've just taken apart are in excellent condition. The plastic bush has some wear and is a little sloppy and the oil seal is very hard and has obviously been leaking. I'll replace those parts, the sealing washers and the leather washers. All the other parts are good to be re-assembled. Once those are back on the bike, I'll go through the same reconditioning process with the front forks as they have both been leaking from the oils seals as well.
John
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Re: Competition Jampots?

Post by dave16mct »

I'd consider the bronze bushes instead of the plastic for the Jampots and the front forks. The plastic ones can swell and stick for seemingly no reason, even after years of use. AMC Classic spares have the broze ones.
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Re: Competition Jampots?

Post by Pharisee »

dave16mct wrote:I'd consider the bronze bushes instead of the plastic for the Jampots and the front forks. The plastic ones can swell and stick for seemingly no reason, even after years of use. AMC Classic spares have the broze ones.
Dave.
The bronze bushes, oil seals etc are winging their way to me from deepest Clifton as we speak :D :D
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clive
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Re: Competition Jampots?

Post by clive »

The competition Jampots have adjustable damping. I have them on one of my road bikes ( cannot say I have noticed any difference). Someone sold on the Jampots as extra to his need after he had completed a rebuild, he showed me a very nice competition 350, it was only when I started rebuilding the Jampots I realised I had the suspension that should have been on his bike!
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Re: Competition Jampots?

Post by Pharisee »

clive wrote:The competition Jampots have adjustable damping. I have them on one of my road bikes ( cannot say I have noticed any difference). Someone sold on the Jampots as extra to his need after he had completed a rebuild, he showed me a very nice competition 350, it was only when I started rebuilding the Jampots I realised I had the suspension that should have been on his bike!
Ahh... that must be what the screw in the bottom of the damper tube is for. I thought it strange that I didn't remember seeing that in the units I built up for my G3/LS. They may be adjustable but certainly not "quickly adjustable" if you have to remove the bottom clevis casting if you need to make an adjustment. Having said that, I guess a good mechanic could whip the shocks off, turn them upside down, unscrew the clevis casting, make an adjustment and have them back on the bike again in the few minutes between races. :lol: :lol:
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Re: Competition Jampots?

Post by bjorn »

When assembled, the CS jampots are indistinguishable from the road bike jampots. So they were stamped with a C for proper identification. I have two 1956 G80CSes and the jampots for those are marked with a C.
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