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Discussion Starter #1
This is probably a stupid question, but what is the difference between a "slipper clutch" and a regular clutch? I've heard the term thrown around and just wanted to know. Thanks.
 
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Discussion Starter #2
I'm not familiar with the exact mechanical differences but from an operational standpoint, the slipper clutch's purpose is to reduce the rear wheel's tendency to "bite and bounce" when aggressively downshifting... or incorrectly downshifting. I believe the 620's have a slipper clutch as standard equipment...the reasoning behind that [ I assume] is that many on the 620 will be less experienced riders and more prone to making shifting mistakes.

I had a few mild instances of rear wheel bounce when I haven't properly matched my engine speed when downshifting...it's pretty spooky and I can see how it could casuse one to lose control of the bike.
 

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Most of the aftermarket slipper clutches for Monsters use a system of ramps inside the clutch hub. When the rear wheel begins to turn faster than the engine, the torque on the hub causes the center of the hub to slide up the ramps, mechanically pushing out the pressure plate, which
lets the clutch slip a bit and preventing (or at least reducing the likelyhood of) the rear wheel from skidding or hopping.

Evidently, some of the competition slipper clutches use a system more like a ratchet, but I haven't seen one in person.

--Fillmore
 

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Only the '04 620s have it.

I believe the 620's have a slipper clutch as standard equipment...the reasoning behind that [ I assume] is that many on the 620 will be less experienced riders and more prone to making shifting mistakes.
And who you calling less experienced? Just because someone chooses a 620 doesn't mean they're a newbie.
 
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Discussion Starter #5
I can votch for the very uneasy feeling when the rear wheel jumps because your speed is higher than the gear you shifted into. :p I am sure happens less often when you get more experience

Tom.
 
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Discussion Starter #6
I am really not trying to sound like an ass, but I am not sure I understand what you guys mean by the rear wheel jumping. Please explain.
 
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Discussion Starter #7
Bigsexy,

Downshift from 5th at 60 MPH to second without blipping the throttle to match engine RPM to rear wheel speed.

The rear wheel will then drive the engine instead of the other way around and thanks to compression and the mass of the engine having to accellerate to meet the new speed...the rear wheel will lock up(Sort of) untill the engine and rear wheel are in sync, causing skidding, hopping, and some drama.

The slipper clutch works like a ratchet and reduces this effect.

Kinda like the mechanism on a Bicycle that only allows power to be applied to the rear sprocket in one direction but through different means in this case.

The things are great for the track, and for folks that might push the bike hard into the corners on the street, and have LOTS of utility for those that might downshift one gear too far going into a corner.
Throttle blipping while braking/ Downshifting is a skill set that takes some time otherwise.

Hope this helps.
S-28
 
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I'll try....

Let's say you are tooling along in 4th or 5th gear and about to enter a curve. You decide to downshift so you can go through the curve in a lower gear. You pull in the clutch and back off the throttle, but don't add some throttle before you let the clutch lever out. If the difference between engine speed and rear wheel speed [via the gears] is enough, the rear wheel will bite...almost as if you have suddenly stomped on the rear brake lever. You might think of it as instantaneous engine braking. :eek:

In the couple of times this has happened to me, the rear wheel squeaked and the bike jerked. I assume the rear wheel is bouncing to some degree when this happens...which is NOT good. I suppose if this was violent enough it could lead to a highside?

Hopefully this makes sense. Perhaps someone else will have a better explanation.

Oh...no offense intended to the 620 riders. I was just assuming what Ducati's motivation was in using the slipper clutch on the 620. I could be wrong about that but I do know that instanaeous engine braking is something you want to avoid!
 
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Discussion Starter #9
Ooops...cross post....yeah...what he said. [smiley=applause.gif]
 

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Most of the aftermarket slipper clutches for Monsters use a system of ramps inside the clutch hub.

<snip>

Evidently, some of the competition slipper clutches use a system more like a ratchet, but I haven't seen one in person.
The Aprilia RSVR uses manifold vacuum to drive the "clutch slipper" according to my friend who owns one... High rpms with closed throttle = a semi-released clutch... Sounds plausible to me...

big
 
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Discussion Starter #11
Slipper clutches are well known at the drags. 6000 hp dragsters use slipper clutches to gradually connect the power train to the rear wheels. They rev it up and dump the clutch pedal ... letting the slipper clutch do the work. In contrast, you'll see bracket racing motorcycles bounce up and down the first 60 feet because they too are dumping the clutch ... only they don't have a slipper clutch to gradually apply the power to the rear wheel. The wheel suddenly grabs the pavement, launches the backend up, the rider ease out some clutch ... it comes down ... lets it out again ... it bounces. If you haven't got a slipper clutch you have to slip it by hand, feeling how much to apply. Kinda cool that the duc uses a slipper clutch. This is a clutch that uses some kind of mechanical invention to gradually ease in the pressure plate against the clutch disk(s) ... allowing power to be applied gradually rather than suddenly.
 

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Slipper clutches are well known at the drags.
Nah, they're different "slipper clutches"...

Bike ones release the clutch a bit when the wheel is trying to turn the engine over, not to allow slip when the engine is trying to drive the bike forwards...

big
 
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Discussion Starter #13
It is a freewheel, just like a bicycle. It allows the engine to stop "pedaling" while you coast. Why would you want this? Well, if you are a racer on the track, and you go into a turn, you can let off the gas fast, and the bike won't slow down quickly. This lets you put all your concentration on using the brakes to get your entry speed perfect and smooth.

When you exit the turn, you want to apply the throttle really smooth too. With a standard engine, transitioning from engine braking to power on you will get a little shudder from drivetrain slack and engine tuning. If you are riding as fast as possible in the turn, this shudder may be enough to put you in a skid. Since the slipper clutch is like a freewheel, you can just slowly roll on the power, and the clutch will smoothly transition between freewheeling and applying power.

You can do everything a slipper clutch can do by squeezing the clutch lever, but it requires a lot of concentration, and the slipper clutch is usually better at it. On the lighter side, a slipper clutch will have more wear on it from all the constant slipping, and the rate of slipping is hard to tune perfectly.

For joe average street use, a slipper clutch isn't necessary. Nice to have? Sure, but so are a lot of other expensive go-fast bits that you would probably want even more.
 
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