Is it just the master cylinder leaking?
Some day I would like to replace my rear calipers (only) with 4 piston type that I believe only PM makes at this time. I'm sure they wouldn't sell the calipers by themselves.

 

When I mentioned temperature I was mentioning the master cylinder being blasted with high heat from the front exhaust pipe. I'll bet that brake fluid is making its way real close to 400+ degrees.

 

With a lot of help from different forums I try to do most of my own maintence. That said I had trouble orginally with stock brakes dealer was never able to get them bleed right. I bought some speed bleeders and 1liter of super blue racing dot 4 brake fluid and 1 liter of typ 200 amber dot 4 fluid. I alternate between the 2 when you have blue in I go to amber that way I can see when I have all the old fluid out. The boiling point on these fluids is 536 degrees and 388 degrees wet. I know have great rear brakes, 2009 Tri-Glide hope this might help.

 

I run the same fluid, I have blue in right now and will pick up some amber when I get ready to flush the system. I like the higher boiling point of the Super blue fluid vs most off the shelf fluids.

 

Was you running this fluid in the performance machine brakes on your trike?

 

Yes I was, except I was running the stock master cylinder, I never ran the PM one due to the problems others were having with it. When I sold the brake system it had a brand new master cylinder PM sent me and said it addressed all the issues, looks like they lie.