Routine chain drive maintenance, though simple, is very important. Chain drive maintenance should be performed before every ride after cleaning the motorcycle. Always refer to the motorcycle owner's manual for service information.1
Regularly inspect the sprocket teeth. Teeth wear will tell you when replacement is necessary. Periodically check the length of the chain. If you are using a very hard sprocket, such as stainless steel or tool steel, the chain may wear out before there is noticable wear on the sprockets. Refer to a service manual for chain length checks.2
Inspect the chain guide. Replace the insert before it wears through to the metal. Some chain guides may appear to be good yet will be worn through to the insert attachment bolts, so look closely.3
The chain slider is also known as a rub plate. Check it often and replace it before the chain starts rubbing on the swing arm. Check the chain rollers visually and by turning them and wiggling them with your hand.4
Always check the chain slack. Once you know what the correct amount of slack is, you can cut a piece of material or yard stick to use as a quick check gauge. This makes a quick and easy check that is accurate and consistent.5
When adjustment is needed, start by loosening the adjusters lock nuts. Inspect the adjusters too. These get a lot of use, so replace them if the wrench flats start to get rounded.6
Use a good fitting socket to loosen the axle nut. Never use adjustable wrenches unless you have no alternative. Loosen the axle nut just enough that the wheel can move back and forth.7
Turn the adjusters in small increments, evenly on both sides of the swing arm. Count the number of "flats" or "points" on the bolt heads to keep track of turns. Use the slack gauge as an easy check, insuring the axle blocks are snug against the adjuster heads. Make certain the sprockets are in alignment with each other.8
Slack should be checked only when the axle blocks are tight against the adjusters. When correct, tighten the axle nut while pushing the wheel against the adjusters. Torque the nut correctly.9
Before securing the lock nuts, turn the adjusters back slightly to load them against the axle blocks. This should only be a very small amount, just enough to create some compression between the swing arm and axle block (1/12th of a turn at the most).10
Lube the chain with a good quality lube such as Silkolene full synthetic or Bel Ray Blue Tac (not needed if o-ring chain). Focus the lube spray at the space between the rollers and chain plates to minimize lube waste.
Honestly, I wash my bike with nothing more than soap and water, 99% of the time. Of course, this includes the possibility of a pressure washer and/or a scrub brush. The chain though, can be particularly difficult to clean given repeated applications of sticky chain lube. Chain lubes are very resistant to water, which is a good thing.
Generally, I ride motocross about once per week. On a typical week, I'll do three to six motos varying from 20 minutes to 40 minutes each, usually on the lesser side. Naturally, it all depends on how I am feeling or if I am short on time (I am old now, so the youngins might say). In between motos, I check my chain and adjust it if necessary. I spin the back wheel as a way of gauging whether or not the chain needs lubed again. I usually end up lubing the chain liberally a couple times each riding week. Trackside, I generally don't worry about how clean the chain is. When the chain is rotating at speed, dirt and grime tend to fly away, so I just lube and go.
Now I have ran into folks who mistakenly think the sprocket teeth require lube. This is false. As the chain rotates around, the chain rollers sit down into the sprocket teeth but they do not turn in there. It is the pins within the rollers of the chain that are turning as the chain bends around. Lube on the teeth would have little to no benefit, it is inside the rollers that matter most. Here lies the secret of an o-ring chain. The o-rings not only keep grit out of the rollers, they also keep lube in. Chain lube generally is not needed on a sealed chain because the lube cannot get in (consult manufacturer for any specific sealed chain as to lube requirements).
Realize how the lube actually works. We want the lube to get into the rollers where it is needed, but we also want it to stay there. Also, there are extreme loads applied to the chain rollers so a lubricant is required that can handle extreme pressure. Given these needs, a chain lube needs to be thin for application purposes. Once it is applied, it should become sticky so it will stay put. To apply lube, slowly and evenly rotate the back tire. Aim the lube nozzle to the inside gaps between the links and rollers and spray the lube in a controlled manner, not fully depressing the spray nozzle. I do this for gaps on the left and on the right. Make sure you spray the lube through at least a couple of full chain rotations.
With my current moto habits, I find my cleaning and lube regimen to be effective. Using a mixture of dish soap and water, I scrub all around the surfaces of the chain, sprocket teeth, swing arm and sliders, then rinse with water. After I finish washing the bike, I use WD-40 on my chain which drives out the water. Only after the chain has dried do I apply chain lube. Sometimes I just wait until I get to the race track on the following week. Again, I do this frequently.
After a while, depending on the lube you use, you'll find you are getting build up in some areas. Corners between parts, spaces between chain links etc. can get mucky over time, even when the bike looks clean. Fortunately, there are plenty of options to help you out.
Wd-40 is a relatively safe product that will cut through many if not all chain lube gunk. The practicality of using it is primarily on surfaces where you can use a rag or brush for spot cleaning, such as on the swing arm, engine cases, shock spring etc. There are many products that can be used similarly such as citrus degreasers, Purple Power (you can get it at Walmart), brake parts cleaners and even specific chain cleaning aerosol sprays.
If your chain is really bad (dirty I mean), you can remove it altogether and soak it in a plastic tub with enough cleaning solution to fully cover the chain. Of course, if you happen to have a parts cleaning tank, that is a bonus for you. Safety parts solvent works well. I prefer to use a water based degreaser such as Purple Power. A degreaser such as this is biodegradable and safe to use. I mix it 1:1 with water and soak the chain for as long as I need. You may still need to use a cleaning brush to scrub the chain. Afterwards, rinse it in warm water. You should follow up with a coating of WD-40 on your clean chain to drive moisture out of the rollers and off the chain. Chances are, you can even get multiple cleanings with your used cleaning solution.
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