So I'm cruisin' on the 33...

[whitelightning99]

...and I take an exit with a stop sign. Put my foot down to steady the bike and the foot slides a foot to the right. Almost drop it. Damn! Look down to see the problem and notice my boot is covered in oil. Double damn! Have to ride a mile or so to investigate. Whole right side of the bike, including the rear tire, is covered in engine oil. Then I notice that there's no oil filler cap. Problem Solved! Hack a piece of my emergency towel, stuff it in the hole, and I'm on the way. Of course, right turns are done at a glacial pace, and no back brake weighs on my mind, but I make it back whole to my haven. An hours cleaning gets rid of most of the grunge, but need to deal with the rear brake. Will try cleaning first, but replacing the pads will probably give piece of mind. So, I guess the moral of the story is to check that cap occasionally. I didn't, and now I'm payin' the price.

[Queestce]

Ha, I know this feeling! I once made a much sillier mistake...

Had just done an oil change on the Monster. I hadn't actually screwed in the filler cap more than a turn or so as I was waiting for the new oil to drop to see where the level was. I thought it would need topping up. Either way, I came back a bit later to check and it looked all good, so I went for a ride. Needless to say I had a simmilar episode and discovered oil ALL OVER my riding jeans and boot. Was quite perplexed for a few seconds and in traffic so I pulled off, saw the empy hole where the filler cap lived, and felt a right fool... Was a good excuse to buy a nice billet DP cap though

Tk

[vgv21]

Never happened to me, I just hand tighten the thing and that's it, in fact, sometimes is difficult to unscrew it (that's when they brake). When I bought the bike, it came with an aftermarket Al plug, but I replaced it with an original plastic one.
No need to change the pads/anything else. You should use brake cleaner, it degreases right away (keep in mind to avoid painted areas and wash everything after). Or just use soap and water...

[stryder]

Years ago I was doing an oil change and started the bike up without the oil cap fitted. Wow! It pumps out a LOT of oily air in a short time so you may not have been riding like that for too long. You may also want to pull the right side mid panel, and clean the oil up from behind the well nuts because they'll get pushed through very easily if oily. Could have been worse.