Mine has regular green stuff in it. Was perfectly clean when I got the bike 3 seasons ago, and now 20k miles later it still looks perfectly fresh and bright green. I see no need to fix things that aren't broken.
I imagine if you filled the system with pee it wouldn't be good in the long term, but we all pissed in a buddy's Jeep's radiator when it overheated and blasted a ton out from a hose that popped off. Between all of us we probably got a gallon or so in there. Drove it the rest of the day, and then flushed/refilled when he got home. No adverse affects.
If you have a clear WP cover, pick whatever color you like. There's regular green, GM orange, "import" pink, Toyota red, Ford turquoise, ect. Engine Ice is purple, but it also costs like 3x as much as anything else and I'm not convinced it helps anything, since it's specific heat is virtually identical to regular coolant and that's what governs heat transfer ability.
And yes, purging/flushing is a MUST if you are changing types. In general, different colors do not mix and can cause adverse reactions. Even if you had green, and are refilling with green, a flush is still a good idea. The Vmax is easy....the filler cap is the highest point on the system, with both sides sloping up toward it. Just rock the bike side to side as you fill and check it after the first ride and top up if needed.
NEVER EVER use tap water to mix with the coolant. Get a couple gallon jugs of distilled water. Not filtered drinking water....that still has minerals added "for taste". You want totally pure h2o and nothing else. The alternative is to buy the "ready to use" mixed antifreeze, but I never bother since it's a rip off...you only get half as much coolant for the same price(sometimes more).