Replacing the Chain and Sprockets on a Motorcycle

It is recommended to replace the front and rear sprockets as a set with the chain. The required number of sprocket teeth and the chain size can be found in the manual. Changing the rear sprocket size by a couple of teeth isn't critical and is practically unnoticeable. To change the gear ratio, it's better to change the front sprocket, because it's cheaper and the kit will be lighter. One tooth on the front is equivalent to three on the rear sprocket. All well-known manufacturers have high-strength chains, so you can fit a thinner chain, and such a kit will be lighter.

Rear sprockets are steel, aluminum or hybrid. The advantages and disadvantages are obvious! Steel ones are durable but heavy. Aluminum ones are light but wear quickly. Hybrid ones (steel teeth, aluminum body) combine the advantages of steel and aluminum but cost more.

Given the variety of sprockets and chains, there are no fixed replacement intervals. Some kits last 30,000 km, others wear out in 6,000 km. So replacement should be based on the condition of the sprockets and chain at a given moment. If the sprocket teeth are hooked or broken, it's time to replace them. Worn sprockets cause rapid chain wear and vice versa.

It's best to buy a chain with an anti-corrosion coating (gold-colored). Such a chain needs less lubrication during maintenance, stays cleaner and dirties the motorcycle less. The higher the strength, the longer it will last. The seals should have grease cavities; simple O-rings don't last long.

A detailed sprocket kit replacement is shown in the video!

The replacement procedure is as follows:

1. Get to the front sprocket by removing and unscrewing all the necessary covers and parts.
2. Bend open the lock washer on the front sprocket.
3. Unscrew the retaining nut on the front sprocket. To do this, put the motorcycle in first gear and press the rear brake. If the wheel still turns, it needs to be locked. You can lock it with a bar through the rear wheel. The easiest and most reliable way is an impact wrench!
4. Remove the chain. If the chain is being thrown away after replacement, you can simply cut a link with an angle grinder. If you need to keep the chain, it's better to break the link carefully with a tool.
5. Replace the front sprocket. Fit the lock washer and put on the retaining nut. The sprocket is installed with the markings facing out.
6. Replace the rear sprocket. This requires removing the wheel. When fitting the new sprocket, tighten its bolts in a two-triangle pattern (each next bolt opposite the previous one). Then refit the wheel.
7. Determine the required length of the new chain before riveting it. To do this, set the tension adjusters to minimum (the chain will stretch in use). Put the chain on the sprockets and pull it as tight as possible. Cut off the excess links. The chain can be shortened by a number of links that is a multiple of two (inner and outer), so that it closes on two inner links for the master link.
8. Join the chain with the master link and rivet it. It's important to check the link width with a caliper so as not to over-press it.
9. Tighten the nut on the front sprocket. Lock the wheel with the brake or a stop if necessary. Bend the lock washer up against the nut.
10. Set the chain tension according to the manual; usually the free play midway between the sprocket axles is about 20–30 mm. It's important to check that the wheel axle position marks are symmetrical on both sides. If the wheel is misaligned, the chain and sprocket will wear faster.
11. Reinstall in reverse order all the parts that were removed to replace the sprockets.

Of all the consumables, sprockets take the longest to replace, and the responsibility is high.

Note:

A special tool makes joining and breaking the chain much easier. Of course, you can get by with a hammer and a punch, but it's very hard to peen the link pins properly.