Would somone be kind enough to explaine to me how the returning oil from the pump is in part diverted to become chain lubricant ? What regulates the flow? Thanks Ian
there should be a clip with a thumb screw on item 26 to allow control of the oil flow to the drive chain.
It's a messy system though, I removed it years ago and blanked off the tank outlet.
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).
thanks for your comment, I've been known to be wrong before.
Please allow me to draw your attention to the chain oiler in the link below, it's identical to the one which was fitted to my 850 MK 2 (which I have owned from new).
As you can see the thumb screw clip I referred to compresses the clear plastic tube and felt thereby regulating the oil flow to the chain.
Hope this helps.
Pity, as it is an amusing piece to talk over in the pub, (remember them?). Not as amusing as the Velo story though.....
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.
good to read your comments again.
You may recall that back in the days when many of us purchased new Commandos we were presented with the excellent factory published 'Norton Commando riders manual'.
From page 19 "Rear chain lubrication" we read this:-
"The rear chain is lubricated by a pipe with felt restrictor from the rear of the oil tank.
The flow can be reduced or cut off as desired by a compression type adjuster on the pipe. After use, ensure that the adjuster is clear of the battery and all electrical components".
Below for your enjoyment, a PDF copy of the manual:-
Hope this helps solve your mystery.
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
- an early undated edition covering early models, part number 062864
- a later edition, also undated but covering models from engine number 220000, part number 064135
- 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.
thank you so much for the information regarding Commando chain oilers.
Unfortunately, I must confess to be somewhat less enthused about them having removed mine over forty years ago.
However for the sake of general interest and your research purposes I have unearthed the offending article and attach a photo for your perusal.
I trust perhaps you will now be able to reconcile the text from the riders manual with the article in the attached photo?
Do please kindly report back to us when your research is concluded.
All the best
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.
I hadn't intended to re-visit this topic, but when recently searching RGM's website for a cam chain adjuster tool I happened upon the elusive item in question.
As existence of this item seems to have been questioned on this thread, it's perhaps appropriate to record it here for posterity:-
06 4875 Chain oiler compressor adjuster.
Also listed by Norvil and Oldbritts.
The Norton Commando Factory parts list 06 5034 also lists the item on the lower part of the 'group 16 page' although it's not illustrated.
Also from the excellent factory Commando service sheets, page 163 tells us this:-
"An adjuster facility has been added to the rear chain oiler regulator assembly (from engine introduction number 302000) by means of an additional clamp, part number 064875.
The clamp is in the form of a compression clip, and is applicable to all previous Commando models utilising rear chain oiler regulator assembly 061669".
the above service sheets are well worth perusing in their entirety.
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?