I have a coolant issue that's making my brain hurt. When riding the valve on top of radiator bubbles a little yet the fan comes on and off as I think it should so no problem there. When cool the rad needs about 50ml of water to bring it back over the fins !!. Have just run it with the cap off and it boils up quite quickly,and boils over. I can only think that coolant is not being circulated hence a boil at some point in the system not in the rad.On the 2015 gasser the water pump is a sealed unit I think so how would I check this. I'm thinking that i should take the pipes off and kick the bike over. Any other ideas chaps?