My brother's Blaster quit running the other day when we were riding. It sounded like he ran out of gas. We got stopped and tried to start it. When he kicked down on the starter, it was really easy and you could hear something spinning. I know something has come loose or broken. When you kick it, the piston isn't moving. Any ideas? Thanks

Sounds like the spring or engagement gear for the kick starter is disabled....

take off the side cover and have a peek.(Oh, drain the oil first.)

If it is not the starter assembly. You probably blew the pistion or even worse yu could have blew the bottom crank bearing out. Go with the starter first and go from there.