Hi, The level in my 86 k100 never seems to change the bike runs great and the fan only comes on in stop and go traffic or when I sit idling, but the overflow bottle coolant never even gets hot. normal?
Thanks
Brian

The level should rise when the engine has reached normal operating temperature because
the bottle is an expansion tank and the radiator cap has a small valve to allow the fluid to be drawn back to the engine cooling system as it cools down.
The fluid in the bottle will never be warm as it is on the end of the line, but if the level never changes I would be checking the hose from the radiator to the bottle to ensure it is not damaged (holed), which can easily occur if someone has been careless when re-fitting the fuel tank. In this case it is possible to be losing fluid from the engine during expansion, but not drawing it back in during cool-down (contraction), so eventually your cooling system level will become depleted but the bottle will still be at the same level.
Hope this helps.

Thanks, I had a few small weeps in the large hoses that I just tightend up , maybe that will help, I had replaced the small hose to the overflow tank and put a new cap on the radiator fill last year , I'll run her for a bit and report back.
Thanks
Brian