Q:

Help needed identifying mystery screws on 1940s tandem

My tandem has two small screws above each bottom bracket, one on each side (so four in total).  I've not seen them on any other bike, and I can't figure out what they're for!  Suggestions so far have been (a) letting water out (except that they're on the top) and (b) putting oil in (except that I didn't think that was how you're meant to service a bottom bracket - I thought you had to take it apart).  I know they're not for an eccentric bracket, as there's other screws elsewhere for that.  Picture of screws on rear bracket here: http://s8.postimage.org/z4evs6791/IMG_1950.jpg

In case it's any help, original bike spec page is here: http://www.nkilgariff.com/CBcats/Cat_40/CB15.jpg

All help much appreciated!

A:

It's hard to tell from your picture because they're out of focus, but they look a bit like grease nipples:

i.e. like the ones in the top left of the picture.  Do they have the little ball bearing in the middle?

A:

I know they're not for an elliptical bracket, as there's other screws elsewhere for that

Elliptical? Do you mean eccentric? Are you sure that's not what they're for? Maybe there's one set of bolts to adjust the orientation, and another to lock it in place.
But there's also this on the spec sheet:

LUBRICATION: "CB" twin force-feed to brackets and head, oilgun and instructions provided.

This would suggest that there are two grease fittings on the bottom bracket. Modern bikes don't have them, but this ain't a modern bike.
The only way to be sure is to take it apart.

