Verbose... just cut to the point, sheesh!I found the info I recvd from Rustygold back in 2017:
"1) Read somewhere on Jamis' faq that the serial number should be up to 10 digits and start with an 'H'.
2) Started looking for a Jamis serial no. decoder...no luck
3) Was pretty sure that it was asian made, as I think they used akisu forks...so, I thought I would try and find out which manufacturer made the Jamis Earth Cruisers.
4) Discovered, made by Hodaka...which I didn't know made bicycles
5) A couple searches later led me to this site...http://www.bikeforums.net/classic-vintage/1042901-asian-serial-number-guide.html which, when I tried to copy and paste the pertinent info...crashed RRB on my computer at work due to the dreaded ISE.
6) That decoder, however, states only for pre-90...and your H1811 didn't quite fit the pattern (3rd digit should have been a letter). An '81, which this pointed to, would have had the triangle cutouts on the rear dropouts.
7) Look for other brands manufactured by Hodaka in the 90's, and check out their serial #s. Some Konas were made by Hodaka...found a reference that stated Kona serial numbers changed in 97/98 or so...so, I looked for pre-97 serial numbers and found that the first two digits do, at least, follow the 'H' (Hodaka) and '1' (year).
8) viola, 1991 "
Might help or not. Run your number against it and see if you get a reasonable answer.