Just found this forum and wanted to say hello; have owned this 1971 Honda 500 since 1976 in one form or another. Rode it for while in a slight custom stock form and in 1978 built it in a Amem softtail frame in the mountain's of NC, long before the internet. Spun a bearing in 1982 and parked it in my tractor shed and life just went on by. Just last week stumbled across a low mileage 71 500 motor for $70 and pulled the poor guy out of the shed after a long (35 year) nap.
Going to rebuild it and put it back on the road for around town. Will post up some pics when and if I find them.
Flip