First thing is to get the rear wheel up off the ground. I did it by putting some boards under my kickstand and using a scissors jack on the opposite side under the frame kinda opposite the kickstand. Make sure everything is stable, you don't want the bike to fall over on you or onto the floor. It's always a good idea to block the front wheel or tie the front brake lever down to keep the bike from rolling. Once the wheel is up, you have several things to loosen and remove. Go ahead and get the chain guard off now and out of the way. Next remove the axle nut and cotter pin , the chain adjuster screws need to be very loose and the drum brake adjuster nut and cam lever need to have the links and nuts removed.
Once all this is loose you should be able to push the rear wheel forward enough to get the chain off. You may have to lift the chain up and over the edge of the rear sprocket and then turn the wheel slowly until the chain rolls off the sprocket. Be careful not to get your fingers caught between the chain and the sprocket!
To get the axle out you'll have to remove the exhaust from just above the kickstand back, it's pretty simple, there's a hex nut that clamps it in place just above the kickstand, loosen it, and the there are two socket head screws that you'll need an allen wrench to remove pretty close to the rear tire, below the exhaust pipe. Now just slide the exhaust pipe back and it's off.
I compared the teeth on the new sprocket to the ones on the old sprocket to make sure there was no significant wear, they looked almost identical in shape and size so I placed the new sprocket on the wheel and installed the hex nuts with a little blue locktite and tightened them in a alternating pattern.
I decided this was a good time to clean it up and hit it with some chrome polish while I could get to all sides of it easily.
Okay, now, if you haven't taken the nut off the axle completely, do it and then you should be able to slide the axle out towards the side you just removed the exhaust pipe from. You might have to wiggle it a bit and if someone can help you hold the tire up and get the tension off the axle it will be a lot easier. Once the axle is out the tire will be free. Be careful, there are spacers on both sides, the drum side spacer will probably fall off when the axle comes out, the sprocket side sits inside the seal about 3/4" so it doesn't fall out as easily. Make sure and keep up with these, you will need them to reinstall the wheel. At this time you will probably have to remove your license plate for clearance, and tilt the wheel a little to get it out. I had to lift the bike a little bit more with the jack, but it rolled out pretty well. The brake drum will fall out if you lean the tire to that side, so be careful and just go ahead and take it out and put it aside where it won't get damaged. This is a good time to check your brake pad wear and see how everything is looking inside the drum. Mine was dirty, but the pads looked great after almost 12,000 miles and I just cleaned it up a bit with some paper towels and put some grease on the ends of the springs, the cam and the anchor pin. Remember that brake dust can contain asbestos, so don't blow it out with an air hose and wearing a respirator won't hurt either.
Even though I didn't plan on changing the front sprocket, I took the cover off and cleaned it up. The area around the sprocket had a lot of gunk on it and it gave me a chance to inspect the sprocket for damage or wear. It looked fine so I just cleaned it with kerosene.
With the brake drum assembly out, I placed the wheel on some boards with the sprocket side up and loosened the six hex nuts holding the old sprocket in place. I compared the teeth on both sprockets to make sure that there wasn't significant wear, which would mean I'd need to replace the chain and front sprocket as well, but as you can see in the picture, the teeth are almost identical and it all looked good so I just bolted the new sprocket on using a little blue lock tite to hold each nut. I tightened the nuts in an alternating pattern, kinda the way you tighten lug nuts on a car tire.
Next I removed the assembly holding the sprocket, it just slides out, and cleaned the inside and repacked the bearings with grease. I kinda cheated here and some mechanics may give me grief over this, but I didn't actually pop the grease seal out and clean out all the old grease and start fresh, I just took a paper towel and wiped out as much as I could and then packed grease into the bearings until it was full and then put the coupling collar back and the dampers back and reassembled it all.
While I had the wheel out I cleaned out the wheel well really good, it was really dirty in there!
I also took the opportunity to clean and polish the chrome wheel while it was out and easy to get to. All the spokes were good and tight and it cleaned up pretty nicely.
I also cleaned my chain really good while it was easily accessible.
Now you are ready to put it all back. Tilt the wheel a little and roll it back under the fender, don't forget to put the axle spacers in as you slide the axle back in place. Again, this would be a good time to have an extra set of hands, but you can do it yourself, I did. Make sure you reattach the brake cam lever bolt and the brake torque link and adjusting nut from the brake cable. Now is the time to get the chain back on the new sprocket. Put the axle nut on and run it in finger tight but you've still got to adjust the chain so don't crank down on it yet. Since I installed a 40 tooth sprocket the diameter is smaller and I had to adjust the wheel back further than it had been before. Make sure you adjust everything evenly on both sides so the wheel is running straight. Get the chain slack set and spin the wheel slowly a few turns just to make sure everything is properly in place and nothing is rubbing or hitting anything. Now, recheck the chain slack, sometimes it might be different after a few revolutions, it should be in place and properly seated on both front and rear sprockets. Make double sure you've properly tightened everything on the axle and brake assemblies and the adjusters, including installing cotter pins. Now you are ready to put that freshly shined exhaust pipe back in place, just slide it on, tighten the nut and install the two cap screws on the bottom side and tighten it all up. The last thing to go back on is the chain guard, let the bike down off the jacks and take the blocks out from under the kickstand. I like to ride the bike a short distance after adjusting the chain and then check the tension again just to make sure it's right. Oh, yeah, don't forget to put your license plate back on!
Okay, fire away, please feel free to correct me on anything I failed to do the right way or correct sequence. Like I said, this was a first for me and I claim no expertise here, so I'm sure some of you can add to this and make it a lot better.
