Yep, Pretorian nailed it! Most bikes keep the starter gear engaged and use a starter clutch to disengage it from the engine. The clutch is a reverse centrifugal clutch which pulls the engaging mechanism outward and away from engagement. Works the same as a centrifugal clutch on kid bikes except they push the engagement mechanism into engagement. Good thing about V-twin's is that the starter clutch is accessible through the side crankcase cover. On older Japanese models like my Yamaha you have to remove the engine and split the cases to fix it.