Everyone here is a God send. I’ve learned more about my bike these past few days then I ever had in 9 years since I’ve been riding her. If you’re ever in NYC and feel like salsa dancing, I run a salsa class and dance party, message me and you’ll be my guests lol
Just a few more questions and I’m set:
1) The coolant that’s in the expansion tank now. Does it have to be emptied when it was just filled by dealer. If Yes, why? IMHO, no. The coolant in the expansion tank is a volume needed to quench hot coolant from the engine to limit evaporation of the water. Water is only 50% of what's in your system and that is what does all the cooling. It's also acts as a reserve for the evaporation that occurs, which is why you monitor that tank level to ensure the cooling system is running full.
2) With bleed screw partial open, and Rad Cap off, I pour the coolant in the radiator and NOT the expansion tank, correct? Correct Because where the Rad Cap is, is the highest point in the coolant system, and as I’m pouring coolant, air will seep out of the bleed bolt, and fill the expansion tank. No, coolant is added separately to the expansion tank. You can't force coolant down the small hose between the radiator and expansion tank, physics doesn't permit it. What can force coolant down that small hose is the pressure in the sealed radiator as system pressure builds due to thermal expansion. That's why when you run the bike you monitor the expansion tank level for rise, because the coolant expands an incompressible fluid, which builds pressure, that lifts the rad cap pressure valve forcing fluid down that hose to the expansion tank. When the engine cools down the coolant contracts and a vacuum in the radiator opens a check valve in the "pressure cap" drawing fluid back from the expansion tank into the radiator.
3) I stop pouring in coolant when radiator is filled, and then afterwards I fill the expansion tank? YES I guess I’ll visually see the radiator filled when it’s at the brim I’m guessing. To the top of the filler neck. There will be a gap between the pressure cap (radiator cap) neck seal seat and the hose outlet. That gap is OK because the rad cap is closed on a liquid solid radiator. If you get it wrong and over fill, no worries, you just have to clean up the mess you made when installing the rad cap.
And to clarify, I’m getting a new Rad Cap, and proper triumph coolant. A new rad cap is warranted if the old one is leaking (which you said it was). Radiator caps are not simply a cap they are a pressure valve that allow flow in two directions based on pressure. A bad cap that does not seal allows water to boil out of the system and air in reducing cooling capacity as it does so. The heat exchanger which is your radiator moves engine heat to the atmosphere like your air conditioner moves heat from your house to the atmosphere. I can give you the formula to calculate the exchange rate but that won't help you get your bike running right. Suffice to say that the cooling system is required to be sealed tight as a drum to work right. A new cap will ensure it's sealed and will lift to vent coolant at the correct pressure.