I seem to remember a round rubber cushion almost an inch thick between the brake linkage and the firewall/cab floor area that kept the pedal from thumping the floor too loudly. I'd suggest finding something like a shock absorber bushing that will fit over the round part of the pedal shaft, even if you have to saw a split in it and then secure it with a hose clamp, etc. Then adjust the plunger stroke on the M/C to be sure the relief port isn't being blocked. By tinkering with the thickness of the rubber bump stop, the pedal height can be changed temporarily until you find the most comfortable position. If you want to make the change permanent, you can unbolt the pedal rod, take it to somebody with a torch, an anvil, and a BFH, and have him heat and flatten the rod enough to drill another hole.
Jerry
