You can easily change the starter drive by removing the flywheel with a puller. The drive can also be disassembled and lubed. Not many pieces are servicable except the garter spring. The one way clutch and or rust has always been the problem in my experiance.
Idle speed could be the culprit if the drive seems to hang up after starting. Too low of an idle and the drive has trouble kicking out. Bump up the idle to 1100 or 1200 RPMs where most Polaris 4 strokes should be set. This also helps make shifting easier but too many and it gets hard to shift again.

 

Stick,
I went though all that,cleaned, took apart and lubed. Then I replaced the bendix, Worked but made funny noises.
Now last nite I replaced the whole thing, starter and drive. It's never sounded better, quit and smooth. Hope this is the lucky one that lasts!!

 

DCop
My 2000 sportsmans starter does the same as yours.

 

My 97 Polaris Explorer 500 starter has always worked like yours, i.e. it stays engaged for a second or so after the engine starts. Has not caused any problem.