when was 600 introduced. I believe various models have been in use since the late '70s early '80s the RD on this bike looks like just prior or the first index from about '84 or so. same era for the brake calipers
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk