That’s why you can find bikes with original timing chains, which have over 150,000-200,000 miles on them! In contrast, some owners prefer to replace their chain after a certain mileage. It’s safe to say that with proper maintenance, timing chains can even last as long as the engine. Since it’s designed to only drive the camshaft, the time chain takes only a little power from the crankshaft.Ĭonsequently, timing chain replacements on motorcycles are very rare. Unlike the drive chain, the timing chain doesn’t have to tolerate a lot of engine power. When Should a Motorcycle Timing Chain Be Replaced? How Long Does a Motorcycle Timing Chain Last? Here’s a great video on how a hydraulic cam chain tensioner works: These tensioners typically feature an “anti-return mechanism,” meaning that they can only move in one direction. It causes the chain to move inwards, which increases the tension and finally eliminates excessive chain slack. The spring or hydraulic pressure forces this small slider/wheel against the chain. Simply put, the tensioner features a wheel or a slider, which is mounted halfway between the two sprockets. Let’s see how they work! How Does the Cam Chain Tensioner Work on a Motorcycle? So, the design of timing chain tensioners varies widely, but basically all do the same thing.
Timing chain tensioner manual#
Hydraulic tensioners use the oil pressure provided by the engine’s oil pump.īesides the more common automatic units, some motorcycles come with a manual tensioner.Īs the name implies, this unit can only be adjusted manually, which requires some extra attention. The automatic motorcycle cam chain tensioners typically use a spring-driven worm, a spring-loaded arm, or even hydraulic power to keep the chain tight. Here’s a great animation on how a timing chain works in a motorcycle: Thanks to this care, timing chains are very durable and many of them virtually last forever. On top of that, it’s lubricated by the engine oil! The timing chain is enclosed in the engine, so it’s completely protected from water and dirt. At first glance, it looks like a simple bicycle chain. Unlike the heavy-duty drive chain (which is also driven by sprockets), the timing chain is a much thinner chain. In the worst-case scenario, the pistons would hit the valves, causing major engine damage. If the valves were not perfectly synchronized with the crankshaft, the valves would move at the wrong time. This role is key, as the valves in the engine have to open and close at a specified time to ensure proper engine operation. In a nutshell, this part is often referred to as the timing chain because it ensures that the valves open and close on time.
But then where does the name “timing chain” come from? The timing chain is also known as the cam chain, as it actually drives the camshaft.
This means that the camshaft RPM is in harmony with the RPM of the engine, even though it rotates more slowly because of the gearing ratio. The crankshaft drives the chain, which transmits power to the camshaft, which finally controls the valves. These sprockets are connected by the timing chain. There’s a smaller sprocket mounted on the crankshaft while the camshaft has a bigger sprocket attached to it. The timing chain in a motorcycle connects the crankshaft to the camshaft. This is where the timing chain comes into play. These valves move continuously when opening and closing the cylinder, which requires some power.Īnd this power comes from the crankshaft! But how does the crankshaft transmit power to the valves? Motorcycle engines feature valves that control the exchange of gases in the engine’s cylinders. 8.1 Related Articles What is the Timing Chain in a Motorcycle?