Are you sure about that?
You could just have your feet re-sized to fit the bike......
(sorry couldn't resist)
I have found that the type of boot can make a big difference. Although I don't have size 13's I was having similar problems when I wore my timberland boots instead of my Oxtar riding boots.
A buddy of mine cut the shifter lever foot peg shorter so he could get his foot under it easier. (this was on a Buell)
.