the X1100C doesn't have a coast valve as it is a complete new design from the old. i will say the X1100C has a much softer stop than the old through the windshield models though. mine has braking and resists rolling when in gear but it will still roll but very slowly. my advice is when parked and in neutral or in gear you should set the park brake.
NopeI was wondering if riding the accelerator a little would sync the engine tranny and slow you down?
Turbos have zero to do with the breaking of the engine. they are after all the compression of the engine. I would bet the tracks have gear reduction in them. It may give them the ability to easily overcome the braking power of the engine
There are numerous high pressure release valves, they limit the amount of pressure the driving pump can put on driven pump.. thus the total torque and top speed, when you add a turbo SWAG has you increase that value so you can use the increased torque of the engine. So a slow stop is not from increasing that valve.
They shop manual is at posted at this link
https://postimg.org/gallery/1awxlcgio/