They won't interchange. If you look at the honda 110 the upper and lower mounts are different widths. If you look at the yamaha rack, they are the same width. Unless you are talking about the unit that just bolts to the grabbar on the back of the trike, but real honda racks bolt to the same area the grabbar does, you have to remove the grabbar and replace it with the rack.
Nicholson 500x (Project)
Nicholson 185s
Nicholson 110 (That takes an atc70 tank)
Ascott 500 head/350x (Project)
Homebuilt Racer Chromoly Suspension 110 (Ragin Runt)
PK Racing Suspension 70
A+ Inc Suspension 70
AWS Aluminum 90 frame
Hi Performance ATC Suspension frame rd350
Hi Performance ATC Suspension frame 90