The horrible piss pot reservoirs are an afront to my eyes and have to go, I may of sourced some blingy black rizoma ones complete with fitting kit When you change out the brake reservoir the rubber tube to the master cylinder also needs changing , does that mean I have to bleed the brakes ??
You shouldn’t have to, as long as you don’t pull the lever while it’s off. For sure you’ll get air in there but it’s above the m/c and will find its way back up into the reservoir. if it were me, I’d do the change then leave it overnight to find its way out. If you want to force it out you could always remove a calliper and push the pads & pistons back into the caliper as far as possible. That will push the fluid back up through the system and the fluid level in the reservoir will rise, pushing any air caught in the new supply pipe up and out.
I'd suggest bleeding (if it were me, a full flush would be in order if I have the res off), simply because it's not a hard job and will remove any guess work of trapped air. As for fluids, I recently changed to Castrol React SRF racing brake fluid which so far hasn't shown any fatigue.
