MY SON WAS RIDING A 2004 YAMAHA YZ250F MOTOCROSS MOTORCYCLE ON 1/7/05 WHEN ON HIS APPROACH TO A JUMP HIS MOTOR QUIT RUNNING. THE CARBURETOR POPPED OUT OF ITS MOUNTING [INTAKE BOOT]. THE CONSEQUENCE WAS THAT AS MY SON WAS COMMITTED TO CLEARING THE JUMP. THE YAMAHA LOST POWER, AND HE CRASHED INTO THE FACE OF THE LANDING HILL. AND BROKE HIS COLLARBONE ON IMPACT. AFTER I MADE SEVERAL INQUIRIES I WAS SURPRISED TO LEARN THAT THIS IS A COMMON PROBLEM WITH THIS MAKE AND MODEL OF MOTORCYCLE SINCE IT INTRODUCTION IN 2001. WHEN I CALLED YAMAHA CUSTOMER RELATIONS I WAS TOLD THAT THERE WASN'T A PROBLEM. MY SON BROKE HIS COLLAR BONE,,WHAT IF IT WAS HIS NECK OR WORSE.THERE SHOULD SEND A LETTER TO EVERYONE WHO BOUGHT A YAMAHA YZ250F AND SEE HOW MANY TIMES THIS HAS HAPPANED AND WHAT THE RESULTING INJURIES WERE. THANK YOU. *AK