i have 01 wr250f and i keep losing coolant through the overflow (overflow tank removed). the bike is not over heating, but as soon as i start it coolant will just come out of the overflow drop by drop. it off the water pump cover and the impeller seems to be in good shape and it rotates with the kick starter. i have rode the bike without any problems, but i don't want to be on a long ride and lose all the coolandt. could it be i have a bad radiator cap?