Motorcycle coolant reservoir change

[bernau]

I have a fairing bike that I’m lazy to take out to release the radiator cap. But I would like to change the coolant, partially is fine.
Can I drain from the water pump coolant drain nut and as it’s a closed system, I think it would pull coolant from the overflow tank due to the siphoning and so I will top that out as it drains . This way I only open one side of the fairing but will only change a certain percentage. I’m ok with doing a few times.

I’ve done this on some cars but not sure if it would work on bike.
I’m doing this partly to see how the coolant looks inside the engine.

 

[Boomer]

Does your coolant flow through the overflow tank while riding? It does in my cars. I periodically suck the coolant out of the overflow tank and replace it with fresh coolant. You verify the flow by seeing how hot the overflow tank gets after riding and getting the engine up to operating temperature for about 30 minutes. In my cars, the tank is so hot, I cannot touch it comfortably.

 

[bernau]

In some cars, if you loosen the rad drain plug without removing the cap, it will draw fluid from the reservoir, so I was wondering if it would work here. Will have to feel the coolant after a ride.

 

[KrisZ]

Most, if not all motorcycles have an overflow coolant bottle. I have not seen one with a pressurized one. Therefore the coolant in this bottle will not readily flow into the system. You need to re-fill though the radiator cap.

 

[George7941]

Most, if not all motorcycles have an overflow coolant bottle. I have not seen one with a pressurized one. Therefore the coolant in this bottle will not readily flow into the system. You need to re-fill though the radiator cap.

This.
While coolant will be drawn back from the tank, it only works when the cooling system is almost full. You will not be able to refill after draining unless you access the system at its highest point (usually the rad cap)