How a Motorcycle Gearbox Works

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Speeding down the road, handling hairpin turns with ease—you may be a skilled rider, but it’s also worth knowing the basics when it comes to how your new or used motorcycle works. Having a better understanding of your gearbox makes you a more knowledgeable biker, and it also makes you appreciate how your motorcycle is powered. Cycle Trader is providing a quick overview on how a motorcycle gearbox works.

Most motorcycles operate using a manual transmission, which typically uses a sequential gearbox with five or six gears. Riders can select their gears manually using a movable gear selector or driver-operated clutch. This is also known as a stick shift transmission or standard transmission. A semi-automatic transmission means the rider can use a traditional gear change without using a manual clutch, and lets you shift through gears manually. An automatic motorcycle transmission, which is less common, shifts through gears without any indicator for the rider.

Just like understanding your motorcycle’s braking system can help keep your bike in working order, you should have a basic idea of the various components of your gearbox. First, it’s worth mentioning that your bike’s gearbox is powered by rotating, interlocking, and sliding “dog teeth” meshed together.

Many riders don’t take the time to look at their gearbox, often relying on a mechanic to explain the parts and gear changes during maintenance or when they’re fixing various components. A gearbox is more than just a clutch and a lever on the side of the bike. The clutch disengages the engine from the transmission, and when you ride and click up or down to select the next gear, you release the clutch for everything to reconnect.

Inside the motorcycle gearbox, the clutch connects the engine to the gearbox and the output shaft—which has a little sprocket where you put the chain over—and connects the gearbox to the rear wheel.

When you pull the clutch lever, a hydraulic or (on some older or classic/vintage motorcycles) cable-operated action separates the sets of clutch plates so the engine and gearbox disconnect. When you shift the gear lever, it mechanically moves a drum in the gearbox and in turn engages one of three (in a six-speed box) “selector forks.”

The selector forks are mounted on two shafts, along with the cogs or gears. Some gears are fixed to those shafts, while others can slide sideways by the forks to engage with the dog teeth on the side of the cogs in a fixed gear.

While it may sound complicated and there are many parts, understanding how each component works in your motorcycle can come in handy if you’re trying to fix your bike or replace an individual part. Take time to look over the inside of your motorcycle’s gearbox to get a basic appreciation for how your bike is powered—it can also make you look like an expert to fellow riders on the road.

If you’re ready to purchase your next new or used motorcycle, be sure to see all the nationwide listings on CycleTrader.com.