Laydown gearbox

may be removed for filling the gearbox. It's the one with the Norton logo on it... It's a bit awkward pouring oil in from a bottle, unless it has a filling tube extension.  I made a spout from a plastic bottle, using the area round the handle.  There's a level plug below and to the rear of this inspection cover with a square head.  Remove that, pour oil in until oil starts to flow from the hole.

Some oil and battery water bottles comes with a spout. Before I got a number of emptied ones which I now use, I used a quite small funnel fitted with a piece of plastic tube.Also once made a gutter, made from a small piece of U-bent aluminium sheet.

If you're in the snowy North :-) it might help to warm the oil a little before pouring in. Just stand the bottle in a container of very hot water for 5-10 minutes.

From rainy England :0

If you happens to have an old gearbox that uses semifluid grease, warming as Michael said makes it possible to get the grease/oil mixture into the box. Not sure but some really old Nortons might have used it.

... the query related to the laydown box that doesn't.

Whenever I check the oil level in my gearbox, there is always some oozing out of the level plug hole.  I haven't been asked to add any for at least two or three thousand miles.  Maybe I grossly overfilled it initially.

Phil, it never occurred to me to use sloppy grease in a Norton box.  I use hypoid gear oil, but you have to make sure it's not going to eat your bronze bushes.