On my Comet and another I had worked on, there is a large washer (Picture Attached) behind the clutch which runs on the narrow flange on the mainshaft which acts as a backstop for the clutch assembly. This washer runs "free" on the flange and at 2.5 inches diameter acts as a rough sliding seal between the clutch assembly and the inside of the primary chaincase, which has in effect a large slot in it to allow for adjusting the primary chain tension.
I could not find any mention of this "washer" in my spares literature and inquired of the Spares Company for the name and part number to use in an article I was going to write on restoring Burman Gearboxes.
However VOC Spars had no record of such a washer and have said - probably rightly, that it is not necessary, because centrifugal force from the clutch throws the oil away from the opening.
Does anyone know any history for this washer please.
BE WARNED the washer can cause a problem - If you take the second cover off the gearbox with the box still on the bike, to gain access to the inside - for instance to change a gear or repack with grease - the mainshaft and clutch assembly can move back and this washer will drop down behind the mainshaft flange. So when you bolt up the mainshaft on reassembly it will clamp up solid onto the washer and chaincase - as has no doubt happened to some previous owner with the one I have photographed and he had tried to turn the engine over and chewed up the washer.
The only solution then is to strip the primary chaincase and clutch to re-locate the washer - a real pain.
The answer is, before taking the gearbox apart, to take off the cover on the chaincase which gives acces to the clutch springs and put a pad of cloth onto the clutch and put the cover back on in order to keep the mainshaft and clutch from moving back while working on the gearbox.
Don't forget to remove the pad when the job is finished !!!
I could not find any mention of this "washer" in my spares literature and inquired of the Spares Company for the name and part number to use in an article I was going to write on restoring Burman Gearboxes.
However VOC Spars had no record of such a washer and have said - probably rightly, that it is not necessary, because centrifugal force from the clutch throws the oil away from the opening.
Does anyone know any history for this washer please.
BE WARNED the washer can cause a problem - If you take the second cover off the gearbox with the box still on the bike, to gain access to the inside - for instance to change a gear or repack with grease - the mainshaft and clutch assembly can move back and this washer will drop down behind the mainshaft flange. So when you bolt up the mainshaft on reassembly it will clamp up solid onto the washer and chaincase - as has no doubt happened to some previous owner with the one I have photographed and he had tried to turn the engine over and chewed up the washer.
The only solution then is to strip the primary chaincase and clutch to re-locate the washer - a real pain.
The answer is, before taking the gearbox apart, to take off the cover on the chaincase which gives acces to the clutch springs and put a pad of cloth onto the clutch and put the cover back on in order to keep the mainshaft and clutch from moving back while working on the gearbox.
Don't forget to remove the pad when the job is finished !!!