Gearbox mainshaft/primary chaincase felt seal

Hi Noccers.

I believe there should be a felt seal held between two circular plates that stops oil leaking from the primary chaincase onto the main shaft of the gearbox. On myDommie the two plates are mounted so that there is no room for the seal. If I reverse the two platesso that the lips on the periferies of the two plates face outwards (currently they face inwards)then a recess is formedaround the centre hole which will hold a felt seal.Question is: should the lips on the plates face inwards or outwards? It might be a trivialquestion, but I don't want to assume that the person who assembled the plates previous to meowning the bike, got it wrong.

Peter M.

hello the felt gose inbetween the two rivited siding plates at the back of the clutch and the hump bit goes inward to face the gearbox , hope this helps yours ajd

G'day Peter,

I came across the same problem with my 1961 Model 50 and as a Commando owner I suspected the plates were incorrectly assembled, which may or may not be the case. Anyway I very carefullycutwith a thin Dremel disk through the X 3 rivets, cleaned the case and slidingdisksThese were then replaced the other way around and repaired with suitable SS nuts andbolts (used 4-40 UNC with Lockltite as these were 'in stock') could also be spot welded etc. Fitted a felt seal which was previously impossible and repair / upgrade works like a champ.

However, during my 650 SS rebuild, (tin work is from the same era 1964) with identical set up, IE no room for felt seal and just the same as the Model 50 back case before I got at it.

So which is correct?

I am happier with some sort of seal, have enough trouble keeping oil inside the chain case as it is, so unless there is evidence to suggest this is not a good thing to do, the 650 chain case will receive the same treatment as the Model 50!!

Comments on a post card please....

Rgds Steve

How crucial is it to have oil in the primary case? It has a minor function in lubricating the clutch rollers when it is released, but otherwise a good chain wax should keep the chain happy, I would have thought. So I wonder if all this leaking tinware is unnecessary. After all, the Inters ran their clutch dry, didn't they?

A quick fix is to put the felt seal just behind the clutch body and in front of the discs. You might need to shim it in some way to get a good fit. eg another felt washer.

Previously tom_mcewen wrote:

How crucial is it to have oil in the primary case? It has a minor function in lubricating the clutch rollers when it is released, but otherwise a good chain wax should keep the chain happy, I would have thought. So I wonder if all this leaking tinware is unnecessary. After all, the Inters ran their clutch dry, didn't they?