Yep. You'll need the master cylinder to.
On the single/twin setup, one other thing to bear in mind is fork twist. It does happen on single disc setups. Remember the old fork braces on the 250 LC's............
You go banging a 4 pad on there with a good disc etc. and it'll increase.
IMO, I'd only ever consider a twin setup for anything more than a quick blast around the lanes, never mind racing...................
Watch the mounting centers of the calipers to. The early bikes ran the 40mm mounts and you'd need a spacer to fit a 4 pad to these..........unless you got a GP billet item
