Almost done with my own conversion so thought I would show a few pics - also a question or two of course.
took off my single 38 caliper and replaced with lower sliders and two 40mm calipers from a 79 R100R that I rebuilt.
I went with a new 13 mm handle bar MC so my switches and double throttle cables would all fit.
As you can see I didn't have room for the double banjo so I did similar to mymindsok using the under tank distributor (used from Repsycle). Since it was there I just used the brake switch from my old MC and had new SS lines made all around.
Overall went together fairly easy in large part due to the outstanding info in olds cool (and snowbum). However I have run into problems with the bleeding. I used speedbleeders on the calipers and after quite a bit of lever pumping was able to push brake fluid without bubbles through first the left and then the right caliper. I did notice that a few minutes into the process some dark liquid swirled into the reservoir from the master cylinder but only for bit and then no more - anyone know what this might be? I thought maybe it was just residue from a new rubber washer or gasket in the MC and probably no big deal or at least I hope so.
Anyway main problem is after this standard bleeding there was no resistance on the brake lever - the pistons moved in the calipers against the rotor but no real pressure.
So I tried all the various inmate tricks (tapping to chase bubbles, pulling fluid with a syringe, lifting the calipers up, etc) but not much luck. Finally put the bike on a left lean to increase the down angle of the MC banjo, released the distributor and put it to one side and angled up so the line would go continuously up to the MC and the brake switch would be the lowest point to free any trapped air in the distributor. And left it overnight with the lever strapped against the handle. After the first night a bit better but no magic as I had heard about. Next day had a few beers while I did more tapping (and cursing) and left it again overnight with the lever strapped. Today there is pretty good pressure although I can still pull the lever all the way back to the grip if I really try. I hope this evenings Jamison toast to the old R90 and one more night with the lever strapped will do it - I will let you all know tomorrow or yell for help.