It is obvious you have a leak or a blown head gasket.
Take radiator cap off, fill radiator with coolant, put cap back on!
The radiator overfill tank is the only spot to fill the radiator. There is no fill cap on the radiator itself.
1) remove radiator cap2) Fill radiator with coolant.3) replace radiator cap4) remove reservior cap5) fill to "fill cold" line6) replace reservior capIf your system not very low or empty you can omit 1-3.
On the radiator.
The Yamaha 850 XS is an air cooled bike. There is no radiator to fill.
Why does the radiator fill up the reservoir
Fill the radiator through the coolant resivour, which is on the passenger side engine compartment.
You have to fill the overflow tank as the radiator does not have a fill cap. Run the engine as you fill the overflow tank but just up to the marks on the tank.
Unless I have drained the block and radiator, I have filled the radiator from my expansion tank in every vehicle I ever had. If you have drained your radiator and it is cold, take off the cap and fill it that way. If you have drained the engine block and have not change your thermostat, you will need to keep filling your expansion tank until everything is filled back up. I recommend changing your thermostat.
Basically when Its Nearly done. Dont fill the whole tub. Every day or day and a half xx
Coolant goes in the radiator or you can also fill the radiator resevoir.
You use the coolent reservoir bottle to fill the radiator. It should fill the rad before it fills the bottle.