A. Clutch basket: Casing that...
A. Clutch basket: Casing that holds clutch internals.
B. Plates: Alternating steel and friction discs.
C. Springs: Apply tension to plates and engage/disengage clutch action.
Believe it or not, some riders have no idea that pulling that little lever on the left clip-on actually disengages the bike's clutch. Many riders have only one concern when it comes to the inner workings of their machines-that they work. But digging into why it works and how it works opens up the fast paced, better than your buddy, potentially high-priced world of high performance.
What Is It?
A clutch is a mechanical coupling that allows the transmission of rotational energy to be engaged and disengaged, thereby isolating the engine from the rest of the driveline components.
What does that mean? It lets the engine spin while the transmission stands still when the clutch lever is pulled, and forces them to both spin together when the lever is out.
How It Works:
In most motorcycle applications the lever on the left bar acts via cable or hydraulic system to engage or disengage the clutch. Remember, the clutch is engaged (engine and transmission rotating together) when the lever is out. When the lever is pulled toward the rider, the coil springs in the clutch are compressed, allowing the stacked clutch plates to move independently.
Barnett's Xavier Romero walked...
Barnett's Xavier Romero walked us through a clutch basket's production.
Robert Fisher of Roaring Toyz...
Robert Fisher of Roaring Toyz has built some of the sickest customs around and has blown out a clutch or two in his racing days. He had this to say about today's clutches: "The OEM plates today are amazing. In some cases they're even better than the aftermarket plates. But where the real performance lies is in the springs. When you add power to these motors the clutch springs just can't handle the stress. I typically run stiffer springs with OEM plates in my high-horsepower applications."
Shane McCoy of McCoy Motorsports...
Shane McCoy of McCoy Motorsports has been building hot exotic customs for years. With myriad stretched, lowered, big-pony builds that are ridden hard under his belt, McCoy has quite a bit of real-world experience with melting clutches. He says: "With many of the R1's the standard oil configuration just doesn't cool the plates adequately. We route an additional oil line through the clutch cover to keep from melting the plates. Anytime you move into high power you need to give the clutch a working over."
The stack of clutch plates are arranged so that plain steel plates and friction plates alternate. One type of plate is connected via splines to the crankshaft while the other plates are connected to an outer basket that drives the input shaft of the transmission.
With the clutch lever pulled in, the springs are compressed-letting the plates spin freely while the engine and transmission are able to spin at different speeds. This makes gearshifts possible while at speed and allows the motor to run freely while the bike is at a standstill.
Key Ingredients And Terms:
Lever: Metal rod, which pivots on a perch located on the left handlebar. Allows rider input to the clutch system.
Clutch Cable Or Hydraulic Lines: These are the mechanisms which translate the rider's input from the lever to the clutch internals..
Friction Plate: These metal plates have multiple sections of friction material attached to them, which grab the steel plates when the clutch is engaged to make the crankshaft and transmission rotate together.
Steel Plate: Smooth metal plates that provide a clean surface for the friction plates to bind to when the clutch is engaged.
Basket: This is the outer housing for the clutch assembly that attaches to the transmission. One set of plates is carried by the basket via keyed grooves or splines.
Springs: Metal coil-type springs that provide pressure to the plates, keeping them in contact when the clutch is engaged.
Slipping The Clutch: Intentionally causing the clutch to be not fully engaged, but not fully disengaged. This allows the engine to rotate faster than the transmission, causing a smoother progression from disengaged to engaged states.
While effective and necessary for riding, this action causes wear of the clutch plates and after extended periods of time causes the clutch to slip on its own and not fully engage when the clutch lever is all the way out.