Clutch modulation

Started by silentbob, April 16, 2009, 03:31:21 PM

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silentbob

I find it interesting that people preach about proper throttle and brake control. 

They would never think of telling someone that they should just buy a bike with traction control and ABS and use the throttle and brake like a light switch. 

So why does almost everyone scoff at bikes that don't come with a slipper clutch and/or tell people that they should install a slipper clutch instead of learning how to properly modulate a stock clutch?


Raux

Clutch modulation is a big part of the MSF. and the onroad portion of the test i took in germany includes proper modulation to keep a walking pace for a bit. the semi-slipper of the 696 has saved me at least once from a missed shift. i've had a bike (M900) without the slipper and now the 696. i love the extra slop safety factor, but i still ride as if it isn't.


swampduc

Quote from: silentbob on April 16, 2009, 03:31:21 PM
I find it interesting that people preach about proper throttle and brake control. 

They would never think of telling someone that they should just buy a bike with traction control and ABS and use the throttle and brake like a light switch. 

So why does almost everyone scoff at bikes that don't come with a slipper clutch and/or tell people that they should install a slipper clutch instead of learning how to properly modulate a stock clutch?


Very good point, SB. I know that I've gotten lazy with the semi-slipper on my 696 - it's my 1st bike since I returned to riding after a couple years off, and I realized how lazy I had gotten riding a 250 (yes, a 250  ;D) on the track a couple of weeks ago. I plan to get back into the habit of riding as if it's a conventional clutch.
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ScottRNelson

You don't really need a slipper clutch on the street if you let the clutch out slowly on downshifts and you're not downshifting at high rpms.

The purpose of a slipper clutch is to keep the rear tire from sliding on downshifts and it will only do that at high rpms when you let the clutch out quickly.  If you wait until rpms drop to 3000 before shifting into a lower gear you're not going to get much rear wheel slippage even if you let the clutch out as fast as you can, because it's only going to need to speed up the engine to 3500-3800 rpms or so.

Even at higher engine speeds, if you take a second or two to let the clutch out it will do the same thing the slipper clutch would be doing for you.

And you can always just blip the throttle to match engine speed on downshifts.
Scott R. Nelson, 2001 XR650L, 2020 KTM 790 Adv R, Meridian, ID

OT

#4
afaik, slipper clutches have only appeared on a few streetbikes as OEM equipment during the last few years......they're expensive.  I would think that 99.9 % of street riders have never used a slipper clutch.

Desert Dust

For street riding, I don't see the need for traction control, a slipper clutch or ABS.

1. Blip the throttle on downshifts.  (slipper clutch)

2. Brake before entering the turn.  (ABS)

3. Roll on the throttle on corner exits. (traction control)

4. Remember, there is no prize money or trophies for street riding, only tickets.  [thumbsup]  [leo]  [moto]

On a Desmocidici at a track these would be welcome pieces of technology.
For my S2R 1K, the aforementioned techniques suffice.   

But that's just my opinion.  ???
 
07 S2R 1K:  "You are not special. You're not a beautiful and unique snowflake. You're the same decaying organic matter as everything else. We're all part of the same compost heap. We're all singing, all dancing crap of the world.”

ScottRNelson

Quote from: Desert Dust on June 02, 2010, 06:48:04 PM
For street riding, I don't see the need for traction control, a slipper clutch or ABS.

2. Brake before entering the turn.  (ABS)
You get caught in the rain and someone unexpectedly pulls out across your path, requiring maximum braking.  You don't think ABS would help you in that case?
Scott R. Nelson, 2001 XR650L, 2020 KTM 790 Adv R, Meridian, ID

Desert Dust

Call me old fashioned, but I like the way my S2R 1K performs on braking and acceleration.
I don't want a computer to adjust my input to the throttle or brake. I wouldn't pay extra for traction control or ABS.

That being said, I rarely ride in the rain, if ever.

It just doesn't rain in SO CAL.  [moto]  ;D
07 S2R 1K:  "You are not special. You're not a beautiful and unique snowflake. You're the same decaying organic matter as everything else. We're all part of the same compost heap. We're all singing, all dancing crap of the world.”

sbrguy

i would guess that abs on the street would help all but the very very expert of riders on dry clean pavement.

even then the 1% that can outbrake the abs, i would even say won't outbrake it in a truly emergency situation, sure they will outbrake abs in a "test" or on a track where there are no unknowns such as a sudden car or other distractions, but throw those in and i'm not sure even an expert track racer will outbrake an abs bike.

Triple J

Quote from: ScottRNelson on June 03, 2010, 05:38:38 AM
You get caught in the rain and someone unexpectedly pulls out across your path, requiring maximum braking.  You don't think ABS would help you in that case?

+1

This is what it's designed for...wet OR dry out. There's also road debris to contend with. ABS is a good thing, and you'll never know it is there until you need it.

He Man

I ride a lot in the city, and ive done both, and as much as i practice, the road conditions are always different, be it diesel oil, kerosene, motor oil, or just plain old garbage juice or gravel thats hiding.   ABS and TC would of saved my ass twice.

duc996

+1...but a good throttle control wouldn't hurt.
"All we ask is to be let alone"
       "Monster S4r"
       "KTM SMC 690"

The Bacon Junkie

I'm a throttle blipper... always have been, always will be.

I've ridden bikes with a slipper clutch and I actually feel less in control than with a standard clutch.  Kinda like driving an automatic car...  I prefer manual.  It just feels better to me.

As far as the ABS goes, I'm not a fan.  Here's why... 

A friend and I were taking a slightly spirited pace up one of the local canyons.  Me on my Monster and him on his BMW K-something-big.  He's an ex=racer and knows how to handle a bike.  He asked me to lead because he wanted to see how my lines and technique was improving and give me feedback.  His BMW has ABS, but it's disabled with a touch of a button. Well, this time when he pushed the disable button, for whatever reason it didn't disengage. He thought it was, but found out the hard way.
  So we're riding along and near the top I wave him by.  We're only maybe 10mph over the posted 35.  (Very tight and twisty and I wasn't very good back then)  So he comes by me and as he gets on the brakes for a right hander, he stands the bike up and goes straight across the road into (luckily) a turnout.  The turn has a bumpy entrance, and as he tipped in, the ABS kicked in, and stopped the braking action.  He wasn't able to get the bike turned because he was counting on having more stopping power, but because of the bumps in the braking zone before the turn, the ABS kept modulating the brakes and he couldn't scrup enough speed.  Without ABS, he would have gotten the bike slowed and turned not problem.  Hell, my meager skills and inadequate stock suspension could make it through the turn okay, he certainly should have. 

In slow tight maneuvers I'll keep a constant throttle, use the rear brake, and modulate the clutch.  One of my moto [leo] friends gave me some insight on that.  Works well enough for me!   [moto] 

Downshifting, even at higher rpm, I blip the throttle to match revs.  That's how I learned to drive a car, that's how I learned to ride a motorcycle. 

Good luck with whatever technique you use and ride safe...


[bacon]
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booger

I usually get a little unsettled when the ABS kicks in driving the cage. Slippers are only needed on the racetrack. Traction control can be accomplished using the hands, feet, and brain.
Only one that might make sense with me is the ABS. And even then, if you ever get into a situation where you're sliding all over the place, do you really think ABS is going to save your ass? I was walking around the lower east side of manhattan once, where all the sidewalk mechanics tend to do their work. Slippery as hell around there, I busted my ass crossing the street. Was like a sheet of black ice in August! Maybe I should buy me some ABS Nike's. ABS would not have saved anyone there. If you're in a situation where there is no traction, what makes you think all those gadgets are going to matter? Can't control traction if there is none to begin with. Part of knowing how to ride is knowing when to ride, ie when it's not raining or snowing. And avoid the oil slicks, don't just ride all over them! Sheesh. Really though, riding a Ducati in any sort of slippery condition is not the best idea.
Everybody got a plan 'till they get punched in the mouth - Mike Tyson

2001 M900Sie - sold
2006 S2R1000 - sold
2008 HM1100S - sold
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2007 S4RT
2007 Vespa LX50 aka "Slowey"
2008 BMW R1200 GSA

Cloner

Quote from: The Bacon Junkie on November 09, 2010, 12:28:49 AM
I'm a throttle blipper... always have been, always will be.
...  I prefer manual.  It just feels better to me.
...  As far as the ABS goes, I'm not a fan. 

I'm with Ryan on this one.  Rev matching works for street use.  Hell, it works for race track use.  I've ridden several bikes with slippers and I simply don't like the way they feel....especially the later Ducati 1098R one where I can feel the damned thing ratcheting through the clutch lever.  It's disconcerting and uncomfortable.

Ditto ABS.  On most bikes the geniuses who program the systems have decided that they need to link front and rear brakes.  Whenever one wheel stops turning they relieve brake system hydraulic pressure to "unlock" it.  However, on a modern streetbike it's not uncommon to lift or nearly lift the rear and have it stop turning at minimal application of the rear brake.  When the rear stops turning the ABS system relieves pressure to BOTH wheels, so stopping distance and absolute performance are compromised. 

To make matters worse the valving to make ABS work is frikkin' heavy.  That's what I want...a bike that an engineer worked years to make lighter......enhanced with a heavy, hydraulic valved system installed by some safety Nazi who's never even ridden a motorcycle and who has no inkling of what is required to ride one well. 

If someone does a system that doesn't link fronts and rears I might consider it for a streetbike.  This type of system might be great for heavy bikes like tourers or Police specials, but for sportbikes I'd like as little between the middle finger of my right hand and the tire as possible, please.
Never appeal to a man's "better nature."  He may not have one.  Invoking his self-interest gives you more leverage.  R.A. Heinlein

'64 Ducati Monza 250
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