Yep, for the 3rd time I've gotten my oil drain plug stuck and ended up rounding off the soft metal hex head! DOH!!! You'd think I would have learned on the first and second time. Well this time it was really stuck... my final solution on this one, drill a hole through the head, stick a Phillips head screwdriver in, warm the engine and then give it a swift kick/push. BINGO, finally it came off. Here are a couple of pictures of the removed drain plug with hole. I installed a new plug with anti seize and used my torque wrench... perhaps I've learned. <grin>
2007 TW "Muley": Cyclerack rear, 55 tooth rear sprocket, Duro Power Grip & Shinko SR241, Clarke tank, Ricochet bash plate, Mule hitch pin quick seat removal, Trail Tech Vapor w/ Dashboard, hardwired Garmin 60csx & 205w, 12vdc adaptor, independent high beam off/on and signal beeper, modified seat.
2000 Yamaha V-star 650 Custom - [sold]
2009 Yamaha WR250R - "Willie Boy" the slimmer faster brother of my Muley.
2009 Hidden Content . Wow, what fun on the highway!
Always remember, anytime you want to change engine oil, rear diff oil, trans oil in a car, lower gear unit oil in an outboard, or any other thing like that you are going to do, remove the fill plug first, to make sure you can get that out, before you remove the drain plug - otherwise you may be screwed having emptied all the lubricant out and then having no way to fill it back up again.
BTW, that was a neat trick, and I would probably just put that back in so I knew I could get it out again. Or, drill out the new plug like that, just in case.
I had the same problem, but I used a nail set which worked excellent.