Take the strain out :-
http://www.lingshondaparts.com/honda_mo ... od_01=6139Look up any bolt and it tells you the thread size and length (not including the bolt head).They are mostly M8 (ie silencer retaining bolts) M10 (ie suspension) and a few M6 (ie the bolts holding lower radiator mount) and M12 (ie frame bolts)
Just be careful with any changes of thread pitch, there are a couple of different ones across the bike (from memory)
The only thing you would need to specify when looking for replacements, is the actual type of bolt, ie the head type/shape.
I just took one of the bolts that secures the rear brake caliper (got a new spare one) measured it and it matches the details on the website.