Real world benefits of the slipper assist clutch

[jedd_imp]

NOw that the 2017 cb comes w/ the slipper assist clutch,
I took a quick peek at the parts needed to convert our existing clutch to the new 2017 slipper assist. At first glance, it looks like about $300 in new 2017 partsis all that's needed.


The new clutch reduces 6 clutch springs down to 3. So that alone should reduce lever pull. But for everyday use and abuse, will this new slipper clutch be much, if not ALOT, better than stock, or is this just NOT enough to convert?

[the Ferret]

interesting. Are you going to make the conversion Jedd?

[johnf514_imp]

Very interested in this. Clutch pull has always been heavier than preferred, and I like to bang down gears while riding enthusiastically and have had the rear step out a few times.

[jedd_imp]

Ferret...I'm thinking of doing it, but not right away b/c I haven't found anything wrong w/ the stock clutch.
The hydraulic clutch is so luxurious to use, I am NOT complaining whatsoever.

I need to go visit my local Honda dealer - they have a 2017 EX on the showroom floor last month I walked in there.
If it's super easy - like one finger easy - to pull the clutch lever on the 2017, This will for sure prompt me to get off my butt and do this.

[Ulvetanna_imp]

It's going to be significant.

[url=https://www.motorcyclistonline.com/mc-garage-video-how-motorcycle-slipper-clutches-work-and-why-theyre-awesome]Ari Henning 'splains.

Here's my experience with them.

I have several bikes with slip/assist clutches and it's extraordinary how light the clutch pull is on these bikes. Nearly effortless, one finger if desired.

There was thread by someone who had test ridden a bike with this type of clutch, and initially the expectations of how it works are misunderstood. The "slip" function only kicks in if the rider really botches a downshift and the engine cannot spin up the the RPM that matches the downshift. Without that slip, the rear wheel, of course, will skid; maybe a little, maybe a lot.

Usually it takes only a tiny intervention of the slipper to correct things and let the engine RPM catch up (or down in this case). This intervention is usually just a few milliseconds, not a long interval that seems like very light engine braking. That slippage is noted at the clutch lever as a light "bounce" or pulsation and isn't much different than sensing when the ABS kicks in at the front brake lever.

The slipper never engages for long periods of time and has nothing at all to do with engine braking.

I have a pretty good comparison between my 2015 ZX-10R, which has a slipper clutch but without assist, and my 2017 Z900, which does have the slip-n-grip clutch.

The ZX-10R has a pretty stiff clutch pull, where the Z900 has the lightest clutch pull of any bike I've ridden. Just effortless. On the other hand, my Wolf Classic 150 has the toughest clutch pull of any bike I own, and is right up there with my old Harleys (mid-2000s). It's a workout. That bike is about 15 HP, where the Kawasakis are in the 115-175 HP range.

The slip feature is for safety only; it's a misunderstanding to think this feature is routinely engaged by racers downshifting for a turn. It really never activates, and if it does, it can be a huge problem, because it's the same thing as pulling in the clutch. That means the racer has blown the corner entry. I would say in all the track days I did on my GSX-R 750, I may have felt it engage two or three times, very briefly.

For those riders who are good at shifting, and aren't having any problems in that regard, the slip feature will very likely never engage. If it does engage, the little pulsation sends a message letting him/her know they've botched the downshift, and the learning process happens pretty quickly.

It's a lot better than learn the hard way by high-siding.

So this feature is an excellent upgrade in all respects; it takes the load of the forearm and helps preserve the wrist from carpal tunnel syndrome by reducing lever effort, and also serves as a safety feature that, for some riders, could be just as valuable as ABS.

If I still had my CB1100, I'd do this upgrade for sure.

Very interested in this. Clutch pull has always been heavier than preferred, and I like to bang down gears while riding enthusiastically and have had the rear step out a few times.

Do it! You'll be happy you did.

[SportsterDoc]

The principle purpose of a slipper clutch is to reduce engine braking and increase rear tire control, especially if that engine braking is done abruptly and while heavily applying the front brake.

An easier pull is a side benefit.

Canyon running with my Sportster 1200 Sport would chirp the rear tire when I got lazy (not lightly blipping the throttle) on downshifting before a turn.

A slipper clutch would reduce that, but I've not had that issue with the 2014 CB1100. Nevada does not have the canyons that I enjoyed in SoCal, but Deer Creek Road (NV highway 158 in the Spring Mountains) is a smooth run on the CB1100.

Think of a slipper clutch as partially pulling the clutch lever when abruptly backing off the throttle.

[Ulvetanna_imp]

The principle purpose of a slipper clutch is to reduce engine braking and increase rear tire control, especially if that engine braking is done abruptly and while heavily applying the front brake.

An easier pull is a side benefit.

Canyon running with my Sportster 1200 Sport would chirp the rear tire when I got lazy (not lightly blipping the throttle) on downshifting before a turn.

A slipper clutch would reduce that, but I've not had that issue with the 2014 CB1100. Nevada does not have the canyons that I enjoyed in SoCal, but Deer Creek Road (NV highway 158 in the Spring Mountains) is a smooth run on the CB1100.

Think of a slipper clutch as partially pulling the clutch lever when abruptly backing off the throttle.

In the broadest sense, yes.

But in the specific technical aspects of performance, engine braking is something that is determined by the tuning of the ECU through fueling adjustments.

Motorcycles today, especially high-performance racing engines, can be very precisely tuned for a variety of engine braking performance parameters.

For example, a WSBK bike can be tuned to increase or reduce engine braking for every turn on the racetrack. And that braking is adjusted automatically in real time by GPS location provided by satellite tracking.

Nicky Hayden crashed once because the GPS signal failed at a critical moment and his bike didn't have the engine braking he expected.

I just bring this up because it's an important point; engine braking can only occur if the engine is actually connected to the drivetrain.

A slipper clutch disconnects the engine and drivetrain until equilibrium is restored. Experienced riders proficient at shifting will likely never have the slip feature activate. If it does activate, even for a really bad shift, it'll only be for a few milliseconds, just long enough for the RPMs to again match up.

But as the post above indicates, the slip feature can partially disengage, provide some engine braking while still preventing serious rear skid.

But to be clear, the slip feature is like an invisible hand on the clutch; its purpose is the pull in the clutch a bit if you don't.

The principle purpose of a slipper clutch is to reduce engine braking and increase rear tire control, especially if that engine braking is done abruptly and while heavily applying the front brake.

An easier pull is a side benefit.

Canyon running with my Sportster 1200 Sport would chirp the rear tire when I got lazy (not lightly blipping the throttle) on downshifting before a turn.

A slipper clutch would reduce that, but I've not had that issue with the 2014 CB1100. Nevada does not have the canyons that I enjoyed in SoCal, but Deer Creek Road (NV highway 158 in the Spring Mountains) is a smooth run on the CB1100.

Think of a slipper clutch as partially pulling the clutch lever when abruptly backing off the throttle.

That is not the case, as Henning explains in the video.

"The whole idea behind a slipper clutch is that it prevents engine over rev and rear-wheel chatter, and helps keep the rear suspension working properly during hard engine braking caused by aggressive downshifts."

A slipper clutch will never, ever activate if the throttle is merely backed off. The deceleration force is nowhere near sufficient enough to separate the clutch plates. This would be a serious control issue because the clutch would suddenly re-engage if the throttle was applied, leading to a lurch. Its design function is to limit rear skidding during a bad, mismatched downshift only.

Henning misrepresents the function of these clutches when he says "no rev-matching required". A slip-n-grip clutch by no means can seamlessly match the revs for a rider in a transparent way. It doesn't remove the responsibility for riding well from the rider. You will darn well know when the clutch is being released by that "invisible hand" and it functions more like a light switch. Certainly, the slip-n-grip is nothing like a seamless, "no-brainer" kind of feature. It's like a crude version of ABS, it'll pull in the clutch for you if you screw up. It's not an "intelligent" feature, it's mechanical, and subject to very significant hysteresis and is not anything like "predictable".

Compare with intelligent ABS systems, which can seem "seamless" and transparent. Not the same thing at all.

I emphasize this point because, just as with ABS, if a rider thinks he or she can get away with not learning to shift, and the the slip-n-grip is just gonna save his/her bacon, they're gonna be very shocked and appalled when they crash because they think the system will prevent all possible losses of control due to poor downshifting technique. Think about what happens if you suddenly pull in the clutch just after chopping the throttle in a turn.

You lose engine braking and will run wide. A huge botch in a downshift will result in just this kind of reaction from a slip-n-grip clutch until it stabilizes.

[Pete Erickson_imp]

My 2012 BMW R1200R has an automotive type dry clutch. Running at low, like parking lot, speeds the throttle response was like an on/off switch. I installed a box to fatten up the fuel mixture and that helped. I finally resorted to keeping the bike in 2ng gear. That made it much better, but lugged the engine.

I did not experience that problem on my '14 CB1100. It had really excellent low speed manners. I don't think I would have gone to the expense of installing a slipper clutch, unless to original clutch was dead.

My 2016 R1200R does have a slipper clutch and it is great. It makes riding the bike, especially in town, super easy. As yet, I have not experienced any problem with lack of engine breaking.

[LongRanger_imp]

My Ducati 620 has an APTC clutch, which is a nightmare to modulate. I don't think the bike makes enough power to warrant a slipper clutch. It's very difficult to ride the bike smoothly at low speeds -- the clutch has a very narrow friction zone and is either fully engaged or fully disengaged. And this is with Ducati's recommended fully-synthetic, very expensive oil. I'm going to replace it with Rotella T6 and see if that helps.

[Ulvetanna_imp]

My 2012 BMW R1200R has an automotive type dry clutch. Running at low, like parking lot, speeds the throttle response was like an on/off switch. I installed a box to fatten up the fuel mixture and that helped. I finally resorted to keeping the bike in 2ng gear. That made it much better, but lugged the engine.

I did not experience that problem on my '14 CB1100. It had really excellent low speed manners. I don't think I would have gone to the expense of installing a slipper clutch, unless to original clutch was dead.

My 2016 R1200R does have a slipper clutch and it is great. It makes riding the bike, especially in town, super easy. As yet, I have not experienced any problem with lack of engine breaking.

Keep in mind, since these things are just now showing up on all kinds of bikes instead of high-performance machines, that many bikes with slipper clutches don't have the "assist" feature.

On the other hand, some with the torque-assist feature don't slip.

I mentioned my '15 ZX-10R, which has a slipper clutch but not a light clutch pull. There is no assist to it. Same with my '12 GSX-R 750, slip but no grip/assist.

Slip/grip is more accurate, as there's really no "assist" mechanism for the rider. As the video 'splains, the ramps in the clutch assembly tighten the plates under acceleration. That lets the designer used fewer or lighter springs. It's a passive assist to the rider.

The Triumph Bonneville family, for example (Street Twin/Cup, Bonneville, etc.) all use a "torque-assist" clutch which allows the lighter springs and gives a pretty light feel to the clutch. But there's no slip feature, so the rear wheel will indeed skid if one messes up a shift.

I think the ASC (Assist Slipper Clutch) is a fantastic feature to have on any bike with a high-torque engine, like the CB1100. It reduces hand fatigue, great for urban riding or long sporting rides with many downshifts, and could definitely help with a screwball or sloppy downshift by maintaining traction.

A very worthwhile upgrade if possible. There could be some other parts or fit conflicts but if not, wow, what an excellent upgrade! I wonder how the clutch feel would be affected, though, with the lighter springs?

My Ducati 620 has an APTC clutch, which is a nightmare to modulate. I don't think the bike makes enough power to warrant a slipper clutch. It's very difficult to ride the bike smoothly at low speeds -- the clutch has a very narrow friction zone and is either fully engaged or fully disengaged. And this is with Ducati's recommended fully-synthetic, very expensive oil. I'm going to replace it with Rotella T6 and see if that helps.

Both my former GSX-R 750 and now my Z900 need to be fully warmed to get the clutch to engage nicely. The slipper feature causes the plates to behave in a funny way until the oil is completely warmed up. The bikes produce an unusual vibration at the lever when letting the clutch out from a stop. After two or three easy launches, it clears up.