Hi Micky, I'm sure you've thoroughly checked the system, but the brakes sticking could be down to lack of lubrication on the rear wheel cylinders where they mount through the back plates. The whole cylinder is supposed to be able to slide so it can re-centre when you lift off the pedal.
My Spyder would drag its brakes for about half a second after releasing the pedal for about the first year until I tracked the problem down to a rear cylinder slider that had picked up some grit in its grease.
I also had an aftermarket master cylinder that would lock the brakes on completely every time you pressed the pedal. Fortunately that happened during the build process so I swapped it for another m/cyl before venturing onto the road.
Final thought - check the steering rack mountings very carefully. If it has solid alloy rack mounts fitted, make sure that there's some means of stopping the rack from sliding laterally.
I've now fitted two sets of alloy rack mounts, one from ebay and one from a reputable Triumph parts supplier, and both sets required the deletion of the 'U' clamp cover that holds down standard rack mounts but also locks the rack in place. With just the solid mounts in place it's only friction that holds the rack stable and once the engine dripped a bit of oil on it, mine came loose and was able to move about half an inch from side to side. This made the steering very unresponsive to the point of it being dangerous on the one occasion I drove it on the road.
I made up a couple of simple steel fillets to stop the rack moving about, but I really don't understand why the solid rack mount kit doesn't contain something suitable. I'll take a picture later so you can see what I mean.
Anyway, best of luck with the fettling and sale.
