I have a 1975 honda 400four super sport, I've owned for 19yrs, all original, what should i ask for it?

All original, above average, runs out hard and strong, a nickel sized ding on the tank, paint is great, seat is ripped but has a removeable cover "not recovered", the only non stock item is the muffler the original rusted through the bottom. Also I had to replace the crank case because I bearing blew & cracked the original 17yrs ago. It has just alittle over 10k miles, I had it parked inside for almost 12yrs, when I bought it it only had 963 miles on it. So anyone got a suggestion what I should ask for it or make me an offer, I can send pics.