Bulleit Handlebar End Caps
 

Bulleit handlebar end caps for your small internal diameter handle bars on a Franken 1970s Sears Ted Williams (Austro Diamler?)

http://bikeforums.net/attachment.php...hmentid=279896
http://bikeforums.net/attachment.php...hmentid=279897
http://bikeforums.net/attachment.php...hmentid=279899
http://bikeforums.net/attachment.php...hmentid=279900

By the way - This sleepy light weight 27 incher has humbled many a road bike... Long Story...

need to store the contents of the bottle in the handlebar, that would be even better.

The rye is better. :p

I prefer Rum, and old rum at that.
http://www.refinedvices.com/newsimages/Extra-c.jpg

I had my fixie set up with the tops of Port bottles (colheita, obviously, can't be too snobbish about these things) as handlebar plugs. Seriously, these things are almost as if just made for the purpose. I also rehabbed a bike for my neighbour, who is a wine merchant, with regular corks as a little personal touch (plus, it's approved by Grant).