ET: Engine (Twin) Main Bearing

[Cyborg]

Mine looks bad, But if it's Standard !!

But am I correct in assuming that breather came from the factory? It is a photo of Len’s Lightning that was shipped to Canada. This is another assumption, but it must be the most original one on the planet. When I last saw it, I was sure some of the air molecules in the tubes came from Stevenage.

 

[Robert Watson]

Hello, The bearing spacer is a labyrinth seal not a scroll as it can be fitted either way round. John.

And even if it was a scroll, turning it around would make no difference. Does a RH threaded rod suddenly become a LH threaded rod if you turn it around?

 

[oexing]

Venting the primary like in that last picture would definitely not please my eyes , noooo way ! - - Nor would the rest of the bike - sorry.
I guess a tiny drilling into the gearbox from high up in the primary case would do. There is only minimum air exchange with temperature variations so a vent maybe in the gearbox dip stick should do.
Just saying, to be discussed anyway . . . .

Vic

 

[Bill Thomas]

But am I correct in assuming that breather came from the factory? It is a photo of Len’s Lightning that was shipped to Canada. This is another assumption, but it must be the most original one on the planet. When I last saw it, I was sure some of the air molecules in the tubes came from Stevenage.

Simon says, No such thing as Standard, So we have an open book, People think mines an Egli or something,
But the frame and engine is Vincent, Even the petrol tank !, Just 2" taller !!, Not that I would care what other people think, It's my Bike and I built it,
A one off. Cheers Bill.

 

[Cyborg]

I guess a tiny drilling into the gearbox from high up in the primary case would do. There is only minimum air exchange with temperature variations so a vent maybe in the gearbox dip stick should do.
Just saying, to be discussed anyway . . . .

Vic

Similar to this.... In the slightly fuzzy photo you can make out the original vent hole in the cable access cover. If you look just behind where the cable enters the gearbox, you can see where a pilot jet was added to help vent things. Done by the Norton factory later on.

 

[Black Flash]

Hello cyborg,
I am surprised about the jet arrangement, as all norton boxes [at least the AMC ones] have a tiny little hole in the inspection cover, just like yours if you look closely at your photo.
It is only just visible, maybe it's almost closed due to excessive pressure on the polishing mob.
Cheers Bernd

 

[Cyborg]

Hello cyborg,
I am surprised about the jet arrangement, as all norton boxes [at least the AMC ones] have a tiny little hole in the inspection cover, just like yours if you look closely at your photo.
It is only just visible, maybe it's almost closed due to excessive pressure on the polishing mob.
Cheers Bernd

Yes.. I mentioned the hole in the access cover, but have no way of knowing if it is the original cover to that box,,, but think it has a good chance of being original. The jet was apparently added for the Mk3 version. Maybe they came with both the hole in the cover and the jet for a while and then they stopped drilling the hole in the cover because the jet was sufficient... not sure. My belly pan extends rearward far enough that any oil or shrapnel coming out of the box will be contained, so I'm good to go either way. Here is a blurb on OldBritts:

Old Britts, Eliminating oil leaks due to pressure buildup in the Commando gearbox

 

[erik]

what do you think ,is there any effect or influence of the half closed ball bearing in relationship of venting the Primary drive? a small Jet like the amc gearbox could be fixed in a remote place . nobody has the risc of getting eye cancer. regards Erik

 

[john998]

And even if it was a scroll, turning it around would make no difference. Does a RH threaded rod suddenly become a LH threaded rod if you turn it around?

Hello Robert, I lost a debate with prof Higgins about the way a big end will screw with bad cages some years ago so I should have known better.
Regards John.