Different drive trains, shift systems for motorbikes

C

Constantine Phaulkon

Senior Member
Joined
Jan 13, 2011
I am completely clueless of how motorbikes work (though I do have a mechanical engineering background), so don't think this is a trick question.

My question is about the different types of drive trains and clutch systems for bikes.

There's chain and shaft for the former, and (from what I've read--I don't even own a motorbike yet but plan to), for the latter, there's automatic (a torque converter I guess, like a dune buggy you rent at tourist resorts), semi-automatic (no hand clutch from what I can tell, just a foot gear change, and I guess the gears just crash into one another), fully automatic (a real motorcycle, with clutch on the left hand and gear change lever(s) on the left foot).

Am I right? Did I leave something out?
 
Most common on big bikes is manual clutch, a 5 or 6 speed gearbox and a chain and sprocket drive to the back wheel, some bikes have a shaft drive (BMW, Yamaha V-max and a few others) and some Harley Davidson use a belt instead of a chain.

On smaller bikes you can have the above or automatic clutch (centrifugal force clutch) and also automatic gears, on most small scooter type bikes an automatic clutch is mated to a variomatic belt system (invented by Leonardo DaVinci actually) -a rubber belt connected to two V-shaped pulleys that depending on the output shaft speed change the gearing.

Reading though the above I am not sure if I have managed to clarify anything or just make it more confusing.... and to further mess it up; bikes use a constant mesh gearbox instead of the type used in cars, meaning that all gears are connected at all times and the change in gear is a matter of choosing what gear to take the output from - a car gear box only connect the gear you choose and the other gears are idle when not in use.

Hope that I did not muddle it up....
Eric
 
The Honda wave is semi automatic, when you select a gear the clutch is disengaged, when your foot is off the gear lever, the clutch engages, gas it and your of (centrifugal clutch)
honda90003.jpg


Hope this helps....
 
Erictheviking said:
Most common on big bikes is manual clutch, a 5 or 6 speed gearbox and a chain and sprocket drive to the back wheel, some bikes have a shaft drive (BMW, Yamaha V-max and a few others) and some Harley Davidson use a belt instead of a chain.

On smaller bikes you can have the above or automatic clutch (centrifugal force clutch) and also automatic gears, on most small scooter type bikes an automatic clutch is mated to a variomatic belt system (invented by Leonardo DaVinci actually) -a rubber belt connected to two V-shaped pulleys that depending on the output shaft speed change the gearing.

Reading though the above I am not sure if I have managed to clarify anything or just make it more confusing.... and to further mess it up; bikes use a constant mesh gearbox instead of the type used in cars, meaning that all gears are connected at all times and the change in gear is a matter of choosing what gear to take the output from - a car gear box only connect the gear you choose and the other gears are idle when not in use.

Hope that I did not muddle it up....
Eric
Click to expand...

I see. That's very interesting as were the other replies. So when we say "automatic" clutch in motorycles we don't mean incompressible fluid is being used, as in automobiles, to transmit power, but rather something else, like the variomatic belt system on scooters, or the centrifugal clutch that eliminates the need for manual clutch plates being brought together. If that is true, then the "wet clutch" is simply a manual clutch rather than dry plates, but not a "automobile style" automatic transmission (which uses incompressible fluid to transmit power).
 
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