I don't know if this will help anyone else, but I just spent a couple weeks without the Red Car because of this. I lost one of my water pump pulley bolts recently. There was nothing in the junkyard so I had to figure out the size to buy something. The bolts have a 10mm head, but are not the standard 10mm size that Honda uses so frequently. On p. 10-7 of the manual, it lists a size of 6x1.0, but this is wrong. They are fatter and very short. If you get them too long, they will hit the water pump housing and make a mess. They are also a flange bolt (they have an integrated washer in the head). The actual size is M7x1.0x10mm. So, M7 is the shaft diameter; 1.0 is the thread pitch; and 10mm is the length. M7 bolts are hard to find and flanged M7 bolts are impossible. You can find M6 and M8 all day long, but not M7. I was not able to find anything anywhere online: not Amazon, not eBay, not even McMaster-Carr. I ended up going to Home Depot and buying a standard M7 bolt with separate washers. My HD had them in stock. It just took me 2 weeks of searching to find them.
Hope this saves someone else a big headache.