IMHO, the very best chain for these bikes is the Diamond XD or XDL. If you can't obtain that (check eBay) the Diamond Powersport is my second choice. Many here already know I am not a fan of O-ring chains, as they are an oxymoron on a motorcycle. For conveyors, they are great.
Also: when you get your new sprockets, run them for at least 100 miles with the old chain FIRST. All modern sprockets are cast, not machined, and they have a fine grit on their teeth that will enter your new chain and damage it, quickly. Watch the valleys between the teeth: when they look smooth and shiny again, THEN install the new chain. If you don't do this in this order, your new chain will last less than 1/2 as long as it would otherwise.
And: when you get the new sprockets: take the countersprocket and grind off about 1mm (up to 2mm, it is not critical) from the tip of each tooth. Honda's sprockets originally had shortened teeth (and a larger base circle, but we can't get those today...
) to make the front sprocket settle more quietly and open the rollers as they entered the more oil-rich up-front area, to held them nab a few molecules of oil into their roller's insides. This was called "pumping" the lube. It happens at both sprockets, but up front it has a better chance of collecting a bit more oil (especially in the 750).
