I used to use 20W but it had become difficult to find anymore so switched to ATF years ago. It works fine. ATF oil viscosity wise is equivalent to 5 or 10 weight motor oil.
5W - 20 and 0W -16 motor oil is readily available but appears to only be available as a fully synthetic oil and it costs more than ATF so have not tried it.
A link to that article would be good if you remember how to find it .
There are hundreds of semi fluid greases that melt at low temperatures.
Link Life chain lube is one we would be all familiar with .
Considering that the kickstart drives through the mainshaft which is in the bottom of gearbox and just how hard it is to kick start a wet sumped engines I doubt that this would be a viable solution to a problem that does not exist except in ones ones own mind and then is easy fixed .
I never see the sense in trying to make old bikes that were not oil tight to start with become oil tight after 50+ years of service .
['I never see the sense in trying to make old bikes that were not oil tight to start with become oil tight after 50+ years of service ...']
Not too sure about that...They leaked because leather, tin shields, bits of felt and a lack of seals and O rings determined that they would, not because it was the best way or that they wanted them that way...
I recently added a viton 'O' ring to the speedo drive housing on my Goldie which had an irritating minor leak...It's now gone. A sealed bearing in the M20 gearbox, for example, seems an obvious choice when the inherent leak in the original set up can rapidly cause damage if the oil level drops too far. It can do that very quickly in my experience...And I'm not going back to using Red Hermetite!:laughing: ...Ian
And after time they leak around the oil scrols because the hole has enlarged and the scrol is no longer able to pump the oil back
They leaked oil from new and period publications were not afraid to state that
So you can modify the decompressor , put sealed bearings in the gearbox ( oil will still leak out the breather )replace the cork tube replace the pushrod cork but it will still leak from the kick start and from the gear change and from the clutch push rod because the corks are not constrained so that can be compresses like a gland
spend forever knocking the bolt holes in a tin primary flush with the surface again replace the felt behind the sliding plate ever 12 months but if you use it it will leak oil because that was not considered a problem back in the 1940's, 50's, 60's ( and in the UK 70's & 80's )and none of the sealing systems are oil tight .
The breather will blow a lot of oil mist out onto the chain, in fact that was a design feature
Now If i was doing a bike that was leak free when new then that is a different matter
