G: Gearbox (Single - Burman) Comet: Seal between the Burman gearbox and Primary Case?

[weevil.knievel]

Hi,

Is it correct that there is nothing preventing oil getting out and dirt getting into the Primary case on a Comet 500? The slotted hole that the Burman shaft pokes into Primary case is totally unsealed right?

Also, given the close proximity of oil and clutch components, is the Comet clutch considered a Wet or Dry clutch?

Regards,

Julian

 

[chankly bore]

It is a dry clutch and the original design is sound if you have a mainshaft seal on the crankshaft and the correct oil and level in the primary chaincase.

 

[clevtrev]

It is a dry clutch and the original design is sound if you have a mainshaft seal on the crankshaft and the correct oil and level in the primary chaincase.

On a Comet..... Since when ?

 

[chankly bore]

Well, it doesn't run in an oil bath like a Honda. The internal construction of the primary case is designed to keep oil mostly on the bottom chain run, even if it gets flung about a bit, hence my remarks on oil level and sealing.

 

[greg brillus]

On several Comets I've done including a pre war model, on the large washer that sits against the splined flange on the gearbox main shaft, I've glued on a cork washer that takes up the gap between the inner face of the steel washer and the alloy face of the inner primary cover.......take into account the end float on the gearbox main shaft by pulling the shaft to the left.......measure this gap as best you can, then glue on a disc of flat sheet cork, then thin it down if needed so it lightly kisses the alloy case.......assemble with a light coat of grease, and this will mostly cure that pesky oil leak.........Good luck with it........Cheers........G.

 

[oexing]

We had that topic recently and I´d have a v-ring for seal, a bit like an oil thrower but with a soft lip sitting axially on a sheet of stainless. So then you can shift the gearbox for chain tensioning by min. 5 mm either way, as long as the lip still acts on the stainless. The v-ring is all rubber so you just pull it on the shaft and push it close to the stainless for a gap of 5-7mm - simple. Same v-ring may go on the outside for keeping dirt and water out of the primary.

Vic

v-ring