Just seeing if anyone has any other ideas. Bike is a 2009 CBR600RR race bike I picked up over the winter. It was crashed and parked for three years. Got it going and motor pulls strong. Lots of HRC kit parts including HRC radiator and samco hoses. Has kit ecu and supposed cams with other motor work possible. I am in Canada and the bike runs normal temps 75-82 Celsius. Not overheating, no etam etc but the 1.1 bar rad cap can't seem to hold the pressure at those temps and coolant goes to the HRC overflow bottle and then out the excess hose every once in a while. Tried two rad caps, the second was from a 2016 r1 which has no coolant issues and is 1.1 bar also. I have bleed and burped the system and ripped it on its side to get the air out....again bike is not overheating just seems to pressurize beyond the 1.1 capacity. Have others with HRC rada run higher pressure caps. Previous owner told me of this issue but I thought a rad cap swap would be the fix. Kind of stumped Thanks
It sounds like the gap between the rad and the rad cap is not closing. The neck that hold the rad cap might be too long. Do you see any repairs in that area? Are you sure it is an HRC rad? I fixed a bike recently that had this issue by changing the rad. You should sell me the bike so I can fix it. Where are you located in Canada?
Taki On the cbr it is a plastic neck that attaches to the hoses ...yes HRC rad and samco hoses....bike is actually for sale as I have two gsxr track bikes which I prefer....in British Columbia.
Cylinder head lift at high rpm's, Basically, it blows the head off momentarily and allows exhaust gas into the cooling system, which in turn, momentarily pressurizes it and forces it into the overflow bottle. Yes, it will still keep normal temps as it happens only for a split second a lap, usually at the highest load. New MLS head gasket and make sure both surfaces are perfect. GL
