I just had a similar issue on a Revo 13.
I'd welcome any telltale tips for spot checking one's drive.
Who knows when our clevis pin vacated, but I'd expect my something like, 'Clevis pins in place, check' is revelant.
My wife and I were on a bay cruise Labor Day when she commented, 'Hey, the drive feels wrong.'
Upon stopping, she pulled the drive and did a quick look and noticed nothing out of sorts. The odd change of resistance in peddling continued.
Pulling the drive a second time and looking closer, we found a trailing edge clevis pin totally gone and the flipper hanging onto the mast by only its own friction. It was loose from the sprocket guard (where the clevis pin would be)and ready to drop once it worked itself down the mast.
Unlike the oringal post in this thread, our mast was still secure.
I'm a newbie with drive mechanics, but it seems the clevis pin took a "vacation" and allowed the flipper to work loose.
Photo top center shows holes in sproket guard and flipper where pin goes.
Ironic, we'd been kicking around the idea of beefing up a trip bag with some spare parts.... This is the exact sort of thing they'd be good for. I think I'll be heading down to OEX Sunset Beach or Southwinds in Irvine soon!
Possible replacement parts from Hobie illustrated PDF:
http://static.hobiecat.com/digital_assets/2012-spring-kayaking-fishing-pa-catalog_1.pdf80010301 STANDARD "V2" Kit
020041 CLEVIS PIN
10860001 LOCK RING
MIRAGEDRIVE"V2" SPARE PARTS KIT I N C L U D ES:
A F I N, " V 2 "
MAST
"V2" SPROCKET,
LOC TITE
CHAIN
CLEVIS PIN AND RING
ZIPPERED POUCH