Greetings,
Due to import fees imposed in the U.S.A., I'm forced to be, how shall I say, "creative" in obtaining parts during the reassembly of my '43 WM20. One component that I'm finding difficult to source on this side of the pond is the cork seal that goes between the inner primary cover and the transmission shaft.

Can anyone give me a reason why this solution wouldn't work to keep the lube where it belongs?






https://www.skf.com/us/products/industrial-seals/power-transmission-seals/radial-shaft-seals/general-industrial-applications/productid-8703

Pictures for the curious:

I purchased the bike from "Dave" (pictured) who was probably as old as the bike.

email (option): simonette.john@mayo.edu

Well I don't think what you did is going to work.

The seal you put in will now make the hole in the primary too small. The clutch sleeve has to fit through this hole and it is only a little bit smaller than the hole. Trying to put the clutch on will just push the seal out the back of the primary.

And your seal is not doing the job of what the cork seal was there for. It is to keep gear oil from leaking past the sleeve gear bushing. The seal needs to be in the sleeve gear, not the primary.

If you can't get the cork seal, make one. Later bikes have felt instead of cork. And even with the cork seal, they still leak a little bit.

email (option): simonette.john@mayo.edu

If the sleeve gear bush #54 in the box is in fairly good condition? Most of the oil that leaks out is through the open bearing #57 and straight onto the ground and doesn't enter the primary case. The best cure for that is to fit a sealed bearing (I remove the inboard seal to allow normal lubrication) Ron

email (option): ronpier@talk21.com

Ron Pier

If the sleeve gear bush #54 in the box is in fairly good condition? Most of the oil that leaks out is through the open bearing #57 and straight onto the ground and doesn't enter the primary case. The best cure for that is to fit a sealed bearing (I remove the inboard seal to allow normal lubrication) Ron

email (option): simonette.john@mayo.edu

We send parts to the US almost daily, I think the duties are paid upfront now.
It might be worth looking again.

https://pesltd.uk/?catalogue=bsa-m20&diagram=catalogues

Mark

email (option): pes.sales@btconnect.com

There should be a small amount of oil in the chaincase (Up to the level plug) This is to lubricate the chain and clutch rollers. The clutch is protected from any of that oil by the bowler hat cover. The tube cork seal is to prevent any oil that seeps from the gearbox past the sleeve gear bush, entering onto the clutch via the back door. Ron

email (option): ronpier@talk21.com

One more thing.
If you use a sealed bearing, nr 57.
Do you still have to fit both rings nr 56 ?

Yes you must, make sure you get them the right way round.

Mark

email (option): pes.sales@btconnect.com