I use an SAE 40 for the engine most of the time...In exceptionally hot weather I'll put SAE 50 in the engine, particularly if I'm doing a long run (100 miles plus) in hot weather...I don't use an SAE 30 at all though I used to when I rode (15 miles) to work throughout the winter and the conditions were sub zero or close to it...I do, and always have, done oil changes at 2000 mile intervals as recommended by BSA apart from running in when they are much more frequent...
I use SAE 40 in the gearbox...
Like Ron I prefer to remove the wheels and clean and repack the bearings periodically....Usually once a year if my mileage is average, twice if I've done a lot of touring...That gives an opportunity for a general inspection of brake shoes etc. as well...
I've changed to using ATF (automatic transmission fluid) in the primary side to help prevent sticking together of the clutch plates as a Triumph type 4 spring clutch is fitted....
I use a light grease for the forks and other areas such as brake cam spindles and rear brake lever pivot etc....I've also fitted modern grease nipples to fasclitate this...
Nothing for the steering head bearings as I used sealed bearings for that application....I've never had a lubrication related engine failure (such as big end) in 50 years of riding BSA singles so I guess I must be doing something right...:relaxed: Ian