The headbadge is on the front of the bike where it says Schwinn. There should be, stamped on that piece of metal, a four digit code. the first three digits are the day of the year it was made, in chronological order. So if it was made on the 365th day of the year(December 31st) of 1980, the code would read 3650. If it was the 240th day of 1985, the code would read 2405.,,,,BD