Another Champion Brake Question

As I'm sure y'all know I recently switched my stock Yamaha mufflers for a set of Cobra slash tip slip ons. Doing this required me to fabricated extension pipes from the Champion kit extensions to make this work.
Now, for my dilema. First off, I did nothing to the brake system. After getting back from a week long trip to New Mexico, I took my Roadie on a test ride. No more than 5 miles from the house the rear brakes started locking up. Took the trike back home, bled the brakes as a precaution. Took another ride and same problem. This time they totally locked up. Did not even touch the rear brakes at all. I was prepared tho having scocket with me to loosen the banjo bolt at the front of the rear brake master cylinder. This released the brakes allowing me to get back home. I even used the rear brakes going home and no issues though, I have a soft brake pedal.
Only idea I have is that the heat from the extensions is causing the brake fluid in the line to expand causing the calipers to lock as I've not had a bit of problems with the rear brakes prior to the muffler replacement. I'm thinking of using exhaust wrap to cut down on the heat from the extensions. Is my thinking on the right track?

sounds like it to me. If all was well before the change and not now and the only change was the exhaust then you have got a good grasp on the issue. The second would be besides getting the heat away from the brakes run the highest temp fluid you can get. DOT 4 has a higher boiling temp then 3. Look into that.

Aftter fighting this issue for a few weeks, :mad: and not having any luck. It still happened after wrapping the extensions. Just happened to notice that the front pipe had pushed against the rear brake linkage. So, after a few adjustments to the alignment of the pipes I finally got about a 1/2" of space between the pipe and linkage. After a couple of short test rides and a couple more minor adjustments maybe it's solved. No brake lock up so far. Now, I will have to make an adjustment to the rear pipe to line up the outlets as the outer one is about an inch higher than the inside. Should be an easy fix,,,,,I hope,,,,