Man is that a cool bike. Didn't know about the vents to cool the front brake. Also why is there two exhaust pipes on the front cylinder (isn't it a vtwin???).
I think the stock size is 33 or 34 mm, race is 37 mm. Mine are 38.1 mm though, or 1.5" OD at the flange. Obviously mine aren't in the same league as the EBR stuff, I leave the welds showing.