Oil and General maintenance

Engine oil in the primary chaincase...not too much, the chain only has to dip into it.

The late WD manuals specified 50 weight oil for the gearbox too. Personally I use an SAE 90 gear oil, but non-hypoid, just in case the stories are true.

Level is the bottom of the threads for the filler plug. Filling is awkward.

There is a manual available on-line.

https://www.wdnorton.nl/Downloads/16h%20M&I%20manual%20200dpi%20by%20courtesy%20of.pdf

Hi Andy and welcome

I got fed up with putting oil in my M50, so went the belt drive route, but that doesn't help you!, I think same as engine ie  40 grade, but I am sure more knowledgeable people than me, will help you……….once again welcome! 

Regards John O

If the chaincase  holds oil for any apreciable time ,I would opt for the thinnest mono grade you can find. As a nice clutch action makes all the difference to the riding experience. Even a 10/40 multigrade (not synthetic) will be better than a 40 or 50 oil. 

.. ATF in the primary chaincase. Works well for me. But will I be able to repeat the trick of getting the chaincase oiltight when I refit after repainting?

Hi Ian, a good coating of Red Rubber grease round the seal surfaces has worked well for me. And its no trouble to clean off.  About 8-10 £ a decent size tin that will not go off and last you out.

.. a lot of trial and error I worked out that the seal is actually between the narrow edges of the sealing band and the corresponding ridges on the inner & outer chaincase rather than on the wide face of the band. I used plumber's silicone on both and grease on the face of the band to help it slide into position.

I was anticipating trouble when I took it off a couple of weeks ago to repaint it (some petrol having dripped onto the paint) but it came off very easily and all the ATF seemed to be present.

But can I do it again? who knows.....

I think the last time I used plumbing sealant I made the mistake of buying Dow Corning (the best),  Getting it off the inner case was an absolute pig . Not doing that again.

... every time!