When I first got my bike I had the same problem exactly. I discovered the the radiator cap had been installed incorrectly from the factory. The cap has two rubber sealing surfaces. One is on the spring loaded plunger that goes down into the neck and seals against the inner surface down inside the neck. The spring tension it's set to release any coolant over 16 psi.The other is under the lid off the cap and this keeps the coolant from escaping the neck area and this directs the coolant out the tube into the over flow tank. No coolant should leave the radiator until after 16 psi is reached and then only the excess as the engine it's almost at running temp. And that's not much coolant. When they installed the cap at the factory on my bike the slid it into position at an angle in the plunger slopped to one side and didn't seal the lower surface down inside the neck and was not holding pressure back. Therefore expelling more coolant than it should when it gets got and the coolant expands. When you start your bike cold look at the level in the recovery tank. Watch it closely as it shouldn't begin to come up until the engine is at least 1/2 to 3/4 to normal running temp and it should only come up maybe and inch our so. Mine would start to come up immediately from the first warmth in the engine and would keep coming up several inches till the bottle was full and as soon as I shut it off the heat soak would set in and blew coolant out the top of the bottle through the over flow Jose and onto the floor behind the engine. The cap must hold pressure or it will displace to much coolant from the radiator when it warms up. To verify the cap was the problem I bought the engine up to temp until the fan came on and then shut the engine off. Now there should be 16 psi under the cap in the radiator. Using welding glovesi slowly opened the cap and there was no pressure and that can't be that way. At first I thought the cap was defective but when I took it all the way out I could see the impression on the wedge cone type plunger going across it and not Around it. I carefully reinstalled the cap feeling for the wedge cone to drop into the lower hole in the neck and the compressed the spring and rotated the lid into place. After this I had no more problems. The coolant level in my bottle sis just above min when cold and doesn't quite reach max when hot. About one inch of movement. Try the pressure test that I did and if you don't have pressure then that is why you are displacing so much coolant.
Sorry for the long post,I tend to rattle on sometimes
Hope this helps, Ridefree
