...and the last time your brake fluid was well and truly changed was????

If the fluid or lines have any contaminants in them (especially the long runs on the rear lines) the performance of the fluid will degrade in and around the rear brake cylinders due to heat, causing the "softness" of the rear brakes that you describe. Might be worth 20 bucks (3-4 bottles) worth of brake fluid and an "In! - Out!" afternoon of frustration and boredom to try clean the crap out of the lines.

2002 Sporty , Ironman 2.5" spring, 2" body, 15 x 7 ROH wheels, K&N, 15 x 10.5 Simex Centipedes, Powerchip 91.

"Never argue with an idiot. They will bring you down to their level then beat you with experience!"