I own a '06 YZ450 with no time on it, its to cold in MN, but when I start it in the garage it leaks a few drops of coolant from the water pump weep hole until warm. Dealer replaced seal, still leaked, then replaced pump shaft, still leaks. Yamaha rep. told dealer not uncommon and will stop once bike broke in. I don't know if I buy it. Anyone here of this?