When one has an "unfindable" slow leak, remember to check the valve
stem/valve core.  Still possible for these to deteriorate over time, even
with caps on.

ChrisR
'90 Westy Auto "Blue Whale"

  >
  > Date:    Sun, 22 Oct 2000 14:13:56 EDT
  > From:    Tom Smith <TSmith5041@AOL.COM>
  > Subject: Re: Tire Repair - Tubes?
  >
  > Had one with the same symptoms however no leaks in the rubber itself. In
fact
  > no leaks ever found but it kept seeping down every week to 10 days. Put
a can
  > of fix-a-flat in it and pumped it back up. It's holding fine now. I
suspect a
  > problem with the bead/sealing area of the wheel.
  >
  > Tom