Gearbox Oil

[johnjag]

Hi all - I have just purchased a genuine BSA Instruction Manual for the 1966 range of A50/65's. (My bike a '66 Spitfire) The oil section says 50 weight oil in the gearbox and yet the Haynes Manual quotes EP90. Having searched the web no one seems clear about this and yet I am more likely to believe a manual produced by BSA than the Haynes one. Any thoughts please?
Regards
John.

[idie]

EP 90 and 50 weight engine oil are both the same weight.

[johnjag]

Thanks Idie - that confirms my thoughts.

[A10 JWO]

Been using 80-90 for years, no issues.

[RogB]

Make sure it's yellow metal safe.

Like this from Westway (see description):-

https://www.ebay.co.uk/itm/5L-Classic-EP80w90-Gear-Oil-GL4-GL-4-80w-90-5-Litres/111669846650?hash=item1a000aa27a:g:-TwAAOSw0Ehdq0sf

[Editor]

That's a worthwhile tip.
Many years ago on a trip to France my mate Brian's A10 sleeve bush (main drive shaft to clutch inner) seized solid. Plenty of fresh oil in the gearbox. I wonder if it was 'standard' EP90? 
Anyway, we stripped, sorted and rebuilt the gearbox on the campsite. Read all about it in a forthcoming edition of The Star.
Chris

[johnjag]

Thanks all for your input.

John.