bought sunn xircuit and original obyss forks are shot after some short travel forks suitable to replace, bombers from turn of 2000, sids or something of a similar ilk.
very nice xircuit.. I raced back in the days on one of those.. rode both 63mm judy xc and first version sids.. were to blond to tell the difference compared with an obsys.. from the pictures i've seen though, old sunns with longer travel forks look like choppers my suggestions would be trying a 60mm rock smock, go rigid, buying an obsys that works, or fixing yours.. good luck mate
The usual Sunn fans popping up to say hi!
My experience of fitting longer forks to Sunn hardtails is that you can happily get away with plus 20mm. So on that bike 75/80mm max and maybe go for a stem 15-20mm shorter than stock to bring the handling back to "neutral". As well as boingy forks, may i suggest a Pace RC31? The original shorter version would work lovely on that