Ok, I've been looking at the two parts bikes in my carport and wondering if I couldn't use two stock right fork legs, two stock rotors and two stock calipers to make a dual disc frt. brk. Everything is symetical and looks like it would bolt up ok, the lower fork leg on the left side being turned around to have a trailing caliper, as opposed to the original leading caliper. But there is the problem of the master cyl., master cyl.s for dual disc set-ups have a different hydraulic ratio. Any sugestions for a BMW dual disc master cyl. that would be suitable to use on a GS?