Oil return line

I have to say that I think Gordon is wrong; neither of the Commandos I have owned have had anything resembling the fitting he describes.

Rather, the flow to the chain is "controlled" by the bit of felt (28) stuffed into the length of clear plastic tube (29).

On my present bike the outlet has been blocked off, as I gather most owners do these days; my memory of the machine I had 40 years ago is that this was not necessary, as the felt gradually silted up with detritus suspended in the oil (some will recall that Velocette, among others more progressive than Norton, fitted felt filters in the main return feed on both the LE and Viper/Venom series).

Pity, as it is an amusing piece to talk over in the pub, (remember them?). Not as amusing as the Velo story though..... 

Jon

Best done with clean thick oil with old paint brush or specialist chain sprays.

Acids and condensation from combustion process are not good for chains.

So many owners blank the original system.

My 1974 Roadster had the thumbscrew device to squeeze the plastic, but it fell apart when I tried to tighten it and the tube had got very hard. Blocked it off and fitted a Scotoiler.

Gordon's info (that his mystery clip was fitted to his Mk II from new) is very interesting, since nothing like it is shown in the parts diagram on the AN website (https://andover-norton.co.uk/en/shop-drawing/71/oil-tank-oil-pipes-junction-block-rear-chain-oiler-and-full-flow-oil-filter).

It would be interesting to know more about how it came to be fitted. 

Gordon,

That link is very helpful, and clearly demonstrates that 1973 850s are supposed to have an adjustable feed to the rear chain from the oil return pipe.

This prompted me to have a look at my copies of the earlier Riders Manuals. To be precise, I consulted

1. an early undated edition covering early models, part number 062864
2. a later edition, also undated but covering models from engine number 220000, part number 064135
3. the 1973 850 manual provided by Gordon, part number 065321

Rear chain lubrication is dealt with on page 19 of all three publications.

Working from last to first, the 850 Manual contains the text quoted by Gordon. Note that this does not illustrate the adjuster or specify its location.

The #220000-on manual has this:

The earliest manual, however, not only specifies the existence of an adjuster, but provides an illustration:

As can be seen, this is nothing like the part that Gordon has, and is located down by the chain just above the Z-plate.

My setup on my MK2a matches Gordon's setup exactly, had the bike since 1982.

Have a clause that "specification may change due to ongoing developments" or something like it to cover differences between handbooks and what was actually fitted. 

Add in that NVT as it was when the 850 came out was living on the breadline, I'm sure that they would fit whatever they could get.

Biggest surprise was that they continued to fit an oiler when they could easily have deleted it (like everyone else had done) and pocketed the money it cost.

Next research step … but perhaps left to someone directly interested (a museum curator, perhaps) — discuss with Andover Norton.

As far as I can see from looking at the relevant pages, AN do not list either the early type illustrated in the relevant Riders Manual, nor the later type which Gordon has provided pictures of, nor is either type evident in the diagrams.

Given their evidently completist attitude to stocking spares, I'm slightly surprised at this omission. I wonder if anyone (a) knows the part numbers for each version (b) has drawings of them.  

Thanks to Gordon's research success in supplying the part number I have been able to discover the same item on the AN website (looking distinctly NOS) https://andover-norton.co.uk/en/shop-details/16399:

Can some clever person discover info about the "taper-controlled" regulator illustrated in the early Riders Manual?

Thanks to the drawing linked above I now know what this thing is for. It fell out when I removed the chainguard today. I guess a previous owner removed all the connecting bits though.

The clip in Julians photo is a Unex clip, still available new. They are stainless with a brass screw.

Available in sizes from 7mm to 40 odd. The pressure rating of them is huge and due to the constricting action they due not 'bulge the pipe like jubilee clips tend to do.