'Pawn Stars' Corey Harrison -- I Dove Off My Bike at 40 MPH ... TO AV

Corey Harrison from "Pawn Stars" flung himself off a moving vehicle Saturday to avoid a MAJOR crash ... and the reality star miraculously lived to tell the tale.

Harrison's family and friends were throwing him a birthday party this weekend at his house ... but before the bash, he left on his motorcycle to grab a few supplies.

Corey says a piece of the bottom fender mount suddenly broke off ... sending his bike into a tailspin at 40 mph. The reality star was faced with two options -- fly into a nearby wall/oncoming traffic, or jump off the bike. He chose door #2.

Harrison was not about to let partygoers down ... so he chose to go to the party instead of the hospital. After the party he took a trip to the ER where he learned he had a broken hand. Doctors surgically placed 8 screws and 2 plates into his busted hand.

Corey couldn't celebrate the party he hoped to have Monday night at the D Hotel and Casino in Vegas ... so they ended up bringing the party to him ... at his humble abode.