I bought this bike...Not much time on it. 1999 YZ400F. But when I flushed the radiator...Problems. I must have washed the corrosion away that caused a couple of pin holes. Anyone try "stop leak" in a motorcycle? Want to be sure it will not hurt the remainder of the system. I hate to spend the money if I can band-aid it...I brought it to a shop...They cannot fix it...Said because of where the pin holes are...Not from rock damage... Thanks for the input!