The serial number on a Schwinn 220 recumbent exercise bicycle is located on the underside of the rear stabilizer bar (the short bar underneath your seat). You have to tip the machine on its side, and you will see a white sticker with a small grid and several numbers printed on it, and that's where your serial number can be found.
Yeah, I know... most difficult to access spot on the whole machine... of course!!
FEBRUARY 1974
I mean bike not bile
On the steering tube
The Schwinn bike serial number H19577 was made in 1951.
Db11944
2003
http://www.re-cycle.com/History/Schwinn/SwnB_Serial.aspx#location
August 1974
1984
Anything I've seen on Schwinn has the k#'s ending K499***, would appreciate any help, thanks.
November of 1981.
June, 1967