hi
on my yamaha dt125r i have recently blown my head gasket and have replaced it but there seems to be a lot of pressure in the header tank and keeps on blowing the cap off also all the water in the radiator goes and when i block the pipe going into the header tank it squirts water all through the joints and i have no experience with engines i think its something to do with the thermostat but unshure where its located can anyone help me out??