1969 Honda CB750
Car collectors are also going for old CB750s, with the number of bikes in collections of five or more cars growing 13% in the past year. Millennials are nuts for these bikes, too, meaning their values are not due strictly to boomer nostalgia. That bodes well for their future.
A unit in #2 condition (excellent but not perfect) is estimated by Hagerty at $32,000–$37,500 USD.