The drive chain of a motorcycle is a very important element of the motorcycle drivetrain. Some bikes also use shafts and belts for the final drive but most motorcycles rely on chain and sprocket setup for the job. The final drive is responsible for transferring the engine power to the rear wheel. It is very important to maintain the final drive system and for that you need to understand the system. Following are the major components of a final drive system followed by the different type of drive chains.
Sprockets are the toothed wheels on which the chain runs. On motorcycles, usually the front sprocket is smaller while the rear one is larger. This means that the rear wheels turns less times as compared to the front sprocket. It is important to keep the sprockets in a healthy condition so that the chain can run smoothly over them. The ratio of number of teeth on rear sprocket to the number of teeth on the front one is the final gearing of your vehicle.
You can also obtain major change in the drivability of the motorcycle by altering the size of sprockets. If this ratio goes up, this means that the rear sprocket is bigger and you will obtain more torque on rear wheel. This will result in better acceleration but would drop the top speed. If the ratio is smaller than stock setup, this means that the rear sprocket is smaller than the stock setup. This final drive setup would result in better top speed, fuel efficiency and wider range of speeds in every gear. However it will cause drop in the acceleration of the vehicle.
It is the most common form of final transfer that functions along with the sprockets to drive the motorcycle. They have been around for a very long time and the functioning has been essentially the same for all these years. There are different types of chains being used on motorcycles these days. While the mainstream street bikes use standard roller type chains, high performance vehicles use O ring chains or X ring chains. The ring chains use rubber rings placed between the plates where they have got grease to keep the links running smooth. These chains are better described separately here.
Standard Roller Chains
These are the most commonly used chains. These chains are seen on most commuter motorcycles as they can’t handle a lot. These chains are not self-lubricating and thus they are more suited to small capacity and low speed vehicles. It is required to lubricate these chains at regular intervals so that the chain keeps running smooth without a lot of wear. Lubricating it properly also ensures that they sprockets don’t wear out quickly and the chain runs without much noise. To lubricate the chains, it is important to use a proper cleaning agent first to clean the chain. After all the grime has been removed from the chain and it has been dried, use a recommended chain lubricant or engine oil to lubricate the chain.Even after lubricating the chain frequently, the standard roller chain hasn’t got sufficient lubrication. This is because the lubricating oil doesn’t get into the internal parts of the chain very easily. Moreover even the chain internals are open to surroundings and thus tend to accumulate dust and dirt. This makes the operation rough and there are times when individual links don’t move smoothly over each other.
Moreover this makes it difficult to clean up and apply lubricant when you do it next. The deposits on the chain not only damage the chain and obstruct smooth operation but also cause wear and tear on the sprockets on both ends. They also carry all this dirt on the sprockets and causes deposits near the front sprocket. So with this chain type, you have to lubricate frequently and the sprockets need to be replaced frequently due to high wear.
O Ring Chains
These chains are used on modern motorcycles, especially the ones with higher speeds. These chains are self-lubricating so they can go longer without lubrication and the operating noise is lower. They also wear less on the inside as unlike standard chains, they are lubricated between the plates. The difference in construction is that they have rubber O Ring present between the chain plates. Present between the rollers are the chain components along with vacuum filled grease for lubrication and they are sealed off with the O Rings. This grease inside the rollers makes this type of chain self-lubricated. When the plates of the chain are put in place, they change the shape and are pressed. That is why they create some drag at low speeds but after a short while when the chain heats up, the drag goes away. These chains are a bit expensive but the advantages like long life of chain & sprockets, better performance and low maintenance justify the cost.
X Ring Chains
These chains are very much similar to the O ring chains except that it has got ring in the shape of X instead of O. just like the O Ring chains, the grease goes into the rollers and then the ring seals it off in its place. With an X Ring chain, the area in contact is less as compared to O Ring chain. This reduces the drag coefficient and thus it has got the same sealing effect with less drag between the chain links. So even at lower speeds, you don’t get as much drag as O Ring chains and the costs don’t differ much between the two. The advantages of this type of chain are very much the same as O Ring chain. Self-lubricating, less maintenance required, less wear to the sprockets and longer life. With the O and X ring chains, it is important to take special care during maintenance as they have complex construction. Also many cleaning and lubricating agents are not meant to be used on these chains. So only recommended fluids should be used on these chains.