It is important if it is used for lubrication, otherwise it wouldn't be there.

Robert Butler

Any help? :-

But it still does not tell you what the oil hole/screw is for. I checked my old Royal Enfield service manual and it says all Enfields have a gearbox oil level screw that you take out and fill the gearbox until oil comes out that hole. It says location of the oil hole varies from model to model between front, back and middle of that end cover. So unless you have another level screw there somewhere, that is most probably what it is. Pretty standard thing on old Brit gearboxes. I know Norton, AMC and BSA boxes had them. But never tinkered with Enfields.

Your workshop manual should give you the procedure for changing gearbox oil which should mention it.

That's certainly a unique set up. But I guess the end cover holds only the neutral selector and the main gear selector ratchet mechanism like most, so no need for it to be filled with oil. Very thorough to provide a little oil hole for the shaft where it passes through, and a little screw to blank it off. Gotta love old British motorbikes. They all had their very own ways of doing things. I have had my eye out for an Indian Bullet 500 for a while so maybe one day I will get to learn about these esoteric Enfieldisms first hand. Great old bikes.

Was this (awful) gearbox lubricated with oil? My experience of these boxes was with the Indian built version. These were lubricated with semi-liquid grease and topped up as necessary with engine oil between lubrication changes.

The Indian boxes had a level plug facing rearward on the inner end cover.

Incidentally, the Indian built gearboxes could be adjusted to improve (!) the gear change by attacking the "stop plate", position 17 in the drawing above. This could give an almost acceptable gear selection. I wonder if the UK built version was the same?

Except every other British gearbox I remember working on has the end cover full of the same oil that the rest of the gearbox swims in, in fact you usually fill the gearbox up with oil through a hole in the end cover. Bit unique having the end cover devoid of oil. Certainly Nortons are full of oil there, and from memory BSA and Triumphs and Ariels. But twas a long time ago for the latter three. Very thoughtful of the Enfield chaps to provide a little oil hole to make up for it though!