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JATownsend said:
The front reservoir holds the fluid that enables the control circuit, while the rear reservoir holds the fluid that actually presses on the brakes. So, as the pads wear the rear fluid goes down. And, the float is quite sensitive to loss of fluid. A teaspoon makes a difference.

The front fluid control circuit is a trapped or closed loop with no loss, except for a leak or failing component.
Right general idea, but a couple differences with the '05s. The rear reservoir, visible through the hole in tupperware at the front of the right saddlebag when the lid is opened) now only supplies fluid to the foot brake master cylinder (the rear control circuit). The front and rear wheel circuits have their supply reservoirs integrated into the Integral pump unit, which is under the left side cover, next to the battery.

In theory, the levels in the control circuits will never go down, because they are isolated from the wheel circuits (which supply the fluid required to compensate for pad wear).

The comment about the wheel circuit causing the control circuit to go up is pure hogwash -- there's no way it can do so. And don't buy into the "no routine fdrain/fill" stuff -- the control circuits need to be bleed regularly, just like any other brake system.

For more info on the similar '02-'04 Integral system arrangements and bleeding, see the HOW link to a bleed procedure document
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