Oil breather

Hi Michael - see attached drawing, not sure how much it helps

Bruce

Surely the oil return goes 'into the tank' while the filler tower will 'breath' to the rear chain, ie your guess I would take as correct.

One would expect that the   exit  breather would be above the engine connection to reduce oil transfer.

Hi Michael,

Not sure if your question was answered, so here goes...

The (untimed) engine breather exits the crankcase, just in front of the engine sprocket, and rises above it to the rear, where a pipe connects it to the oil tank. Another pipe then connects from the oil tank (on the turret of the DeLux version) venting any mist down to the upper front of the chainguard. See photo of pipe & location.

The breather is very susceptible to damage from a loose chain. This is a design flaw, rectified at engine No 106838 (& all Electra).

23367 is indeed the correct PO No. of the breather pipe - although the one shown on the NOC Spares Website appears to be shaped incorrectly? Again, see my picture below.

When the engine is next apart, I strongly recommend re-siting the breather as shown.

I came across this for sale ad on Car and Classic for a 61 jubilee Deluxe. I thought it might be useful for some assembly details as it looks well aged but somewhat untouched and original looking. I’m not affiliated with machine nor owner so I can’t properly cite the photos. Maybe someone here? 
https://www.carandclassic.com/l/C1623265

My solution for a better crankcase breather on my Navigator:

A hole drilled behind the left cylinder and a one way valve fitted to the hose leading to the oil tank.

The original breather is blocked off.

I also fitted the valve to my 59 Norton Jubilee Deluxe, it is hidden behind the fairing.

This is the valve from VACO also used on Mercedes Benz engines

Is that the Vernier gauge that was free with Practical Motorist magazine sometime back in the 1970s?