I took off the passenger peg mounting plates off my Speedmaster, I think they are ugly. Then I noticed that I could screw the pegs into the lower plate mounting hole.
The pegs are still fine for an occasional passenger and also serve as an alternate location when laying on the tank at speed or for cramp relief during long rides.
I fashioned a small additional chain guard under the upper right plate mounting hole and plugged the left side upper hole with a finished bolt.
To align the passenger pegs I tried several spacing washers under the peg until the peg was vertical.
