Yes, you can do it, but have you ever done it before? If not, watch some youtube videos. It's not hard, just a pain in the a** if you screw it up. I have never done it on the CB1100, but most bikes are alike in this respect. If it is like any other I have done, this is what I do...
You will also need a new (I'd get OEM Honda) crankcase gasket to go between the case and the block. You will also need tools to strip the old gasket off, new plastic paint scrapers work well, plastic razor blades, a brand new wood-chisel if you are VERY careful. Be careful doing this job, b/c you do not want to make imperfections in the surface of the block. This will make you gasket seal poorly, and you will get an oil leak. You will need gasket sealer. And something to catch some oil that will spill out. Be gentle with everything!
Prep - drink two beers, turn on the radio/smartphone/CD player. Get a chair to sit in that will be comfortable working in that area of the bike (a low one).
1. Remove the old one. Don't be a jamoke - get the right sized ratchet. I think it will be an 8mm or 10mm (most are). Gently loosen the bolts, work your way around the gasket, loosening each of them a few twist at a time (not one at a time) until they are all loose. Once they are started you can remove them with your fingers. if you are lucky, the cover will come off on its own. If it doesn't, GENTLY tap it with a rubber mallet until it falls off.
2. Remove the old gasket from the block. If you are lucky, most will come off with the cover, but if you are like me, you are never lucky, and lots of the old gasket will remain caked to the block's contact surface. There are many ways to do this next step (and I am sure others will point out why mine is wrong), I like to hose it down with some WD/40, and leave it for a few hours. This seems to soften the gasket a bit. Then I VERY carefully scrape off all I can with a plastic paint scraper, this should get most of it, but sometimes not, and anything that is left I remove VERY carefully with a brand new razor blade or wood chisel, being careful not to ever let the blade dig down into the metal. Keep it very flat.
3. Clean it up with gas, or whatever toxic solvent you have sitting around - MEK, paint thinner, gas, etc. just make sure both sides are VERY clean. At this point check the bottom of that cover area and make certain that nothing has fallen down there. If there is anything, wipe it out with a clean cloth.
4. Take you new case cover and put some gasket sealer on the contact surface. You don't need to go nuts if you put too much it will be a mess. Make sure all the holes aligned well. Gently press the cover down into the sealer. Be careful not to get gasket sealer on the block side of your cover.
Intermission - Go drink two more beers. Wonder why they always play the same s*** on the radio. Screw around in your garage. Basically, give the gasket 30 mins minutes to set up and get a little tacky. You can even wait overnight if you want.
5. Take your cover, and gentle and carefully apply clean engine oil to the block side of the contact surface. Again, you don't need to do a ton, it will just make a mess.
6. Place the cover gently back in place, and put the screws back (add red thread locker if you want, but JUST A TINY DAB!) in the same way you took them out, by hand until the meet resistance, then a few gentle turns each, so the cover goes on in a flatish way, not one corner here, then another one, then another one. Some people will say "finger tight" then 1/4 turn more, but you are making the gasket with pressure, so maybe a full turn to a turn and a half. Just do not over torque it, because block metal is softer than you think, and stripping a hold in you engine sucks in many, many ways.
7. Leave it alone, let everything dry overnight before cleaning or riding or anything. Then you should be good to go! The next time someone takes the cover off, because you have oiled one side of the gasket, the gasket will stay with the cover and the block will be clean.
