That's a Minefield and a half
ABS II was first up to say 2002/3 when the twin spark models came out with "Integral" braking
ABS II (2) was a standard fluid from master cylinder to the brake calliper system through a large alloy block mechanism, where the pressure reduction chambers are and the system was quite effective!
I liked the fact that even "if" they failed and you got the alternate flashing ABS lamps you got full power brakes but no ABS.
This system usually had the older Brembo callipers with the big circles around the Brembo name on the outside face of each calliper
Integral braking The first change was the ABS warning lights instead of two close together rectangular warning lights which flashed on off if all was well until you got moving
The Integral systems have two separate lamps one blinks rapidly as the system performs its self check, whilst the other just alternates on and off (Once self checks are done the lamp (s) will flash on and off until the system sees the wheels turning via siganls from the speed sensors
First Evolution Integral braking (Servo assisted plus Linked ) had 2 same size reservoirs on the ABS unit for the "wheel" circuits
This is the main difference Integral Servo Assist brakes have 4 circuits which are independent of each other front and rear control circuits and front and rear wheel circuits. The second evolution of these ABS units had a larger front than rear reservoir on the ABS block as there were issues with the front brakes needing twice as much fluid as the rear (pad wear) and this was the first mod that I saw
They also used up rear pads at a horrendous rate if you hard on the brakes at all!
All evolutions of the Integral Servo assist brakes have a horrendous back up system, which is laughingly called "Residual braking" If this system sees any fault its default action is to flash that horrible warning triangle and turn off servo assistance!!
Fluid changes are better done to the letter, but, I actually just do all the circuits annually on my 1200GS to try and preserve the ABS function by keeping the fluid fresh
The next Development was on the 2007 models of 1200 series where they changed to a car type system thankfully similar to the old ABS II where you retained full power brakes even if you had a brake failure!
but they have sometimes have issues with sticking brushes in the ABS units
Hope that is useful
