6. Replace The SprocketsMounting Sprocket

Before you install the new chain, you’ll need to replace the sprockets. To remove the rear wheel, first loosen the chain adjusters three full turns and snug up the lock nuts to hold them in place. Remove the axle nut and axle. Lay the wheel down sprocket-up. Using a socket, remove the nuts from the studs securing the sprocket in a crisscross pattern. Slide the old sprocket free. If the stud threads are greasy, clean them with contact cleaner. (If you’ve been neglectful in your wheel cleaning because the sprocket was in the way, now would be a good time to take care of any mung sullying your wheel.)

Place the new sprocket on the studs. If you’re unsure of the orientation, the number of teeth on the sprocket is usually stamped on the side facing out. Screw the nuts down finger tight. Set your torque wrench to half of the value specified in your factory service manual and tighten the nuts in a crisscrossing pattern. Once all nuts are torqued halfway, set the full torque value on your wrench and tighten the nuts again. If you tighten the nuts down to their full -torque setting in one step, you run the risk of stripping the threads. Remount the wheel and loosely fasten the axle nut.

Since you’ve already loosened the countershaft sprocket, you should be able to spin the nut free. Before you pull the sprocket off, take a look at it and any spacers positioning it on the countershaft. Don’t worry if the OE sprocket has noise-reducing rubber on the sprocket; most aftermarket sprockets don’t. While you have the sprocket off the countershaft, take a quick look at the seal with the engine case. You shouldn’t see any leakage. Take advantage of the easy access you have with the sprocket removed to clean all the encrusted chain goop from the surrounding area. Clean the countershaft, paying particular attention to the threads for the nut, with contact cleaner. Once the contact cleaner is dry, slide the sprocket onto the shaft. Don’t worry about the nut(s) yet. You’ll torque it down once the chain is installed. Clip-type sprockets can have the clip pushed into place with a big screwdriver.