Just went through this myself. Timing chain inspection cover was leaking. A wise forumite suggested replacing the cheesy rubber gasket with the paper/metal sandwich one. Part # 34761-04A. The $2 gasket came in a kit with the gasket and slightly redesigned inspection cover. $23 - ouch. While I was at it I decided to change the tranny/primary fluid to Red Line 75/90. The derby cover gasket had me stressed out until I put a little permatex on the back of it to hold it in place. I then tried torqueing the torx 27s in accordance with the manual. Two of them stripped (the torx heads, not the threads) before I reached the torque. Grrrrrrrrrr. I went and bought some 1/4 -20 allen head machine screws and replaced all six cause I was worried about uneven torque on the derby cover. This time I let the torque wrench sit and torqued them all by feel with the allen wrench. Now I'm happy. My sporty's got new oil, the oil is staying inside the case, and I'm satisfied My primary/tranny will be good for another 4000 miles or so.
I was able to pop the stuck torx bolts off by dremeling a slot into them and then placing a screwdriver into the slot and tapping with a hammer. When I buttoned everything up I used engine assembly oil to keep the derby cover o-ring in place. This seemed to work great.
Just had the same experience with a stripped Torx screw on the derby cover. Didn't tilt the bike upright so I lost a couple of ounces of fluid. My new Rule #1: Check the Forum before starting any project. Duh!