I've got a 26 special. You don't have to remove the cat. Approach the 17mm drain plug from the RIGHT side of the bike with an open end wrench. A socket won't fit, even with a swivel. It's a bit hard to see, but you can get it on there to break it loose and tighten it. You can unscrew the drain with your fingers, but it's tight and helps if you have smallish hands. You can reach up from under the bike, between the "cut out" in the cat and the right frame rail, and pretty much get your fingers on the plug. It is do-able. The only issue is the gearbox is going to drain over part of the cat. You can make a tinfoil deflector, or just spray it off with carb cleaner afterwards. No matter what, you will have oil cooking off upon startup. It's a bit of a messy job, but not that bad really. Follow the spec... 500cc of 75-140. Ignore the side plug... it's a fill plug NOT a level check plug, the correct level will be about 1/4 inch or so below the bottom of the side fill. Much easier to get a long funnel and use the traditional top fill plug. All in all, it's fairly easy.
