Inner Primary Chaincase/mainshaft oil seal

Information relating to the Matchless G5 or AJS Model 8 350cc Lightweight
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Martin.S
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Location: Bristol UK

Inner Primary Chaincase/mainshaft oil seal

Post by Martin.S »

I don't know what you call it but the steel pressings that hold the mainshaft felt seal behind the clutch - this one was obviously leaking as it was plastered in Red Hermatite - so I drilled out the spot welds. Inside were some what I can only describe as elastic bands. Is this assembly available?
I seem to recall but yet to find a reference to someone turning up some alloy ones and using an O ring as a seal for their Commando.
IMG_20180817_204421 smaller.jpg
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clanger9
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Re: Inner Primary Chaincase/mainshaft oil seal

Post by clanger9 »

Yes, it's available from club spares: "910101 FLOATING SEAL KIT"
Cheap & easy to fit!
1989 Moto Morini Dart 350
1993 Ducati 750SS
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Martin.S
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Location: Bristol UK

Re: Inner Primary Chaincase/mainshaft oil seal

Post by Martin.S »

Thanks Paul, £7.54 - Excellent.
Does the felt seal included fit inside the two discs or around the mainshaft?
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clanger9
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Re: Inner Primary Chaincase/mainshaft oil seal

Post by clanger9 »

It goes between the discs - you fit a disc either side with the felt circle in between & pop rivet the assembly together. Once the felt has got some oil on it, it swells to fit the mainshaft. Here's a photo of mine from a while back (ignore the oil leak...)
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1989 Moto Morini Dart 350
1993 Ducati 750SS
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Martin.S
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Location: Bristol UK

Re: Inner Primary Chaincase/mainshaft oil seal

Post by Martin.S »

Ah, that's what I thought, so nothing seals the steel discs to the alloy chaincase - what I imagine the elastic band type material on mine was trying to do?
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clanger9
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Re: Inner Primary Chaincase/mainshaft oil seal

Post by clanger9 »

That's right - there's no seal between the discs and the casing. No need, because it's just a gentle splash here (and there's a reasonable amount of "springiness" in the plates to hold them tight against the casing...)
1989 Moto Morini Dart 350
1993 Ducati 750SS
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Ozmadman
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Re: Inner Primary Chaincase/mainshaft oil seal

Post by Ozmadman »

More to keep the dirt out than the oil in I think!
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
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