ebay sells kits
search cb750 bolt kits
vintagecb750.com (free shipping on orders over $150, so make a list) (or cb750supply.com, free shipping over $100) has a slew of stuff you could prob use, search bolt(s) and you can order packs of a variety of hex head bolts and an array of fasteners, washers, etc
i always thought those two sites are the same guy, since the sites are designed very much alike, but they apparently ship from different locations. i dunno tho.