front disc warming up

[daveb]

got the bike out of the shed to day, freewheeling felt heavy, brake binding not an issue got to work RHS front disc lot hotter the LHS disc. lifted front wheel rotated by hand 1/4 to 1/3 free rotation.
rode home no issues, desided to clean pots and caliper. 1 piston I could push using my thumbs with a bit of force the other piston no go had to use a clamp, got piston out most of way, bloody crud on piston, had to clean it about 3 or 4 times each time getting the piston out a little further. on last piston press in with clamp all of a sudden pop straight in, now the piston is free.

tested bike, by lifting front wheel again, 1 to 1.5 rotations, sorted.

on my old TDM850 the front brakes seized on after 30,000miles, warped both front discs cost me quite a few quid to get it sorted. It could have been a lot worse as I was on the motorway at motorway speed, the bike slowed at a reasonable speed, it felt like the bike had run out of fuel. its not much fun riding a bike with only a rear brake even at low speed

So I am mind full of what can go wrong.