Sadly, not a lot! They are the old design with iron barrel and head, and overhead valves operated by pushrods. Not one of Honda's best designs, that's why they shifted to alloy head and overhead cam after a couple of years. Many parts are simply not available now, including the front brake torque arm and bushes (common M.O.T. fail), swing arms which rot from the inside, and suddenly collapse without warning (bloody dangerous, even at very low speed) seat bases rot out, and nobody makes replicas. Head gasket is just a copper ring, with "o" rings sealing the pushrod tunnels. I loved mine to bits many years ago, but parts were difficult to get even 25yrs ago, these days the only option is used parts, but that's no good for top end gasket sets, and most parts for them are in the states, which doubles the price and then a bit more time they get here
With an M.O.T. it might scrape £500, otherwise it's a case of take what you can get for it, or keep it for an ornament.
