My new to my ‘01 Valkyrie clutch master cylinder window was a bit brown but not bad. I decided to change fluid anyway. When I emptied out the cylinder it was coated on the bottom with brown mud.

Looks like the PO only added fluid when needed and never went further. I disassembled the master and cleaned it all up. After about 1/2 hr of bleeding the system, I have clutch again. Luckily, none of the mud was in the line.
Now on to the front brakes.