Exactly how does a motorcycle clutch work?

9 replies to this topic
  • cjs

Posted September 11, 2008 - 11:57 PM


I checked howstuffworks.com and a few other sites - very light on details

Referring to the diagram below ..

Pulling in the clutch handle actuates the clutch slave cylinder (22), pulling in on the push rod (13). The push rod pulls back on the inner clutch plate (5). Does the outer clutch hub (1) come back with it?

Looks like it does. So now (5) and (1) are pulled back. Now what? I'm guessing that the clutch discs are what make the transition smooth, but since they're toothed on both sides, they must have to slide out to rub against each other. Also, what's the deal with the springs (8) .. how do they come into play?

If you treat the clutch as a "black box" with an input gear and an output gear, I'm guessing those gears are located on (1). Which is the output and which is the input?

Thanks guys.

Posted Image

  • wormstrangler

Posted September 12, 2008 - 12:16 AM


I'm interested in the answers to this. I've never understood how a clutch really works.

  • big paul

Posted September 12, 2008 - 12:34 AM


Pulling in the clutch handle actuates the clutch slave cylinder (22), pulling in on the push rod (13). The push rod pulls back on the inner clutch plate (5). Does the outer clutch hub (1) come back with it?

No it doesnt. By pulling the clutch the push rod gets PUSHED outside (to the left) this moves the clutchplate cover (7) also to the left, that releases tension the clutchfeathers (8) pass on to the clutch plates. Now with with less friction between plates the outer clutchplates (11) wich are connected to the outer clutch cage (1) can move freely from the inner clutch plates (12) connected to the inner cage. (5)

So there you have it: your clutch is disengaged!

Sorry for the bad english.. technical terms are hard!

  • xrmarty

Posted September 12, 2008 - 10:45 PM


I'm gonna over simplify it alot. By pulling the clutch lever you release the preasure on the friction disks and plates (#11 & #12). With reduced pressure they are able to "slip" by past each other, hence you get "no go", no power transfered to the basket (#1), hence no power to rear wheel. Note how they are stacked against each other. The clutch springs (#8) keep the friction disks and plates (#11 and #12) tightly against each other. When they are tight against each other they all spin together with the basket (#1). Once you get the basket to spin -- you get the rear wheel to spin.

You really need to do a clutch job to get a good feeling for how all the parts interact with each other. So, don't be shy. Tear into it:thumbsup:

  • jkent27

Posted September 13, 2008 - 03:50 AM


There are some good videos on youtube that show how to split the case,rebuild your clutch and other fun stuff. No diagram will be as good as watching someone actually do it :thumbsup:

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  • 07RMZ450RC4ME

Posted September 13, 2008 - 07:00 AM


Let out, go, let out faster, go faster, pull in, slow down, feather, go a little, That's how it works.

Sorry couldn't resist

  • Farmr123

Posted September 14, 2008 - 11:04 AM


To add to the confusion, if you look in the diagram, you will see part # 11 has ears on the outside, with the inside being smooth, and part # 12 has notches on the inside, with the outside being smooth. When you release the clutch lever, you are allowing the inner and outer parts of the clutch housing (#1 and #7) to squeeze together from pressure from the springs. This squeezing causes friction between parts 11 & 12, causing the inner & outer parts of the cage to rotate together. One side of the cage is connected to the engine crankshaft, and the other side turns the transmission.
When you pull in the clutch lever, you overcome the pressure from the springs, and allow the clutch housing halves to spread apart, taking pressure off of the plates (#11 & #12) allowing the engine to spin without the transmission.

  • Racer24

Posted September 14, 2008 - 12:29 PM


primary gear on the crank spins the gear on the clutch basket..now the primary gear shaft (input shaft) fits into the hole in the basket..but when the basket turns it doesnt mean it is spinnging the transmission shaft. thats where the clutch hub comes in..now the clutch hub has splines that line up with the splines on the input shaft..so when the hub spins the input shaft spins.. Now the only way to transfer the power from the crank to the clutch basket to the clutch hub are the friction and steel plates.....simple right...now the friction plates fit into the basket while the steel plates have teeth in that fit into the clutch hub. The clutch stack usually starts and ends with a friction plate with steel plates inbetween each friction plate...Now the pressure plate applies pressure on the stack that way they are sandwhiched together..so now when the basket moves the steel plates will move with it as well as the inner hub which in turn spins the shaft..when you pull the clutch a actuator (sp?) pushes a rod to compress the pressure plate springs to release tention on the friction and steel plates..now they are spinning freely and the hub and basket are spinning independently

  • Gadsen

Posted September 14, 2008 - 12:51 PM


Engine power is tramsmitted via t he basket. Note how the friction disc are "keyed" to the basket. The unner hub has splines and steel plates are keyed to the inner hub. Basket is driven by the engine, hub drives the transmission. Clutch plated are alternated, ie friction, steel, friction, steel etc. The outer part of the basket is the pressure plate and it holds all the disc together with spring pressure. When you apply the clutch, you push this away and the disc float and slip.

  • x2468

Posted September 14, 2008 - 01:15 PM


I wish there was a video of this working. there is a cool vid on youtube of the rekluse working. i always thought the clutch basket moved in and out over the clutch plates, thats why the clutch basket wears the way it does. i guess i thought wrong.

but why have two loose connections through which to transfer power? 1 between the friction plates and the steal plates, and one between the basket and the friction plates?

what happens when u shift to neatral?

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