Idle curiosity

[mcatrophy]

Background: The YCC-S controller has a normal running speed for clutch engagement and disengagement (nominally 1800 and 1300 rpm IIRC). But, when the engine is cold, the fast idle speed is above the engagement speed, so the engagement and disengagement speeds are set significantly higher.

I've had the pleasure of owning an '06 and a '10, and their cold running characteristics are a little different. My normal practice with my '06 was to let the bike warm up until one bar showed on the gauge. By this time the idle speed was nearly at its hot speed, and clutch engagement was pretty normal. In contrast, my '10 holds its fast idle until two or three bars are showing, which takes significantly longer, and the clutch engagement remains at the higher levels. Being an impatient sort, I don't like having to wait for the actual drop in idle before moving off.

With this fast engagement speed, it means revving the bike to move from rest, and normal change speeds can leave the clutch continually slipping in 2nd and higher gears.

The curious thing is, and here's the meat of the question, if I continue riding like this, even when the engine is fully warm (4 bars showing), the clutch engagement speed can still be high.

So, WHAT TELLS THE YCC-S WHEN TO REDUCE THE ENGAGEMENT/DISENGAGEMENT SPEEDS TO NORMAL?

As far as I can see, there is no electrical connection between the fast idle mechanism. My '10's behaviour suggests YCC-S doesn't use the measured temperature, as indicated by the gauge.

I have a sneaky suspicion that the system waits until the engine is seen by the ECU to be idling at the hot setting, and only then will the YCC-S brings its control speeds to normal. So, if you start driving from cold and don't come to rest, it continues to use the "cold" engagement/disengagement speeds.

Anyone know if this is the case?

 

[BwanaDik]

The fast idle is controled by some sort of mechanical "melting wax" mechanism, correct?

So what you're saying is that, if you were to simply ride off when the bike is cold and never slow down enough to come back to hot idle, the clutch engagement point will still be at the high setting when you shift?

I'll see what mine does tomorrow.

 

[mcatrophy]

The fast idle is controled by some sort of mechanical "melting wax" mechanism, correct?

...

That's my belief. (I seem to remember Ionbeam - or was it Ignacio? - did a "chapter and verse" on this.)

...

So what you're saying is that, if you were to simply ride off when the bike is cold and never slow down enough to come back to hot idle, the clutch engagement point will still be at the high setting when you shift?

...

That's how mine seems to behave.

 

[BwanaDik]

Well, I took a stab at simulating this tonight. I fired her up and headed down the driveway within 30 seconds. Yes, high RPM before engagement, basicly slipping all the way (200 ft driveway). As we're not blessed here with 'roundabouts I sort of did a California Stop at the end of the street. Wizzed around the neighborhood without letting the RPM's drop below 2000 and the clutch never disengauged (except, obviously, when shifting).

I never had an engagement problem, it pulled right in on shifts from 1-2 and 2-3 without any bars showing on the gauge. Actually, when she's cold, I'm real easy on the shifting and shift at low RPM's until she's warmed up. It's usually pretty lurchy (is that a word?) and bucks around some but she's always done that so I never paid it much attention. I've never done the 1/2 throttle, 5,000 RPM shift when she's cold (the butter smooth shift mode) so I don't know what that would do. I'll try that tomorrow if I get a chance.

I'm usually showing one bar by the time I leave the sub-division. That's a minute at most in the driveway and a 1/4 mile run to the main stop sign. How long does it take for your bike to hit the first bar?

If it's slipping above 1800 RPM after one bar is showing, you might have a YCCS problem.

Where's Ionbeam?

 

[mcatrophy]

Well, I took a stab at simulating this tonight. I fired her up and headed down the driveway within 30 seconds. Yes, high RPM before engagement, basicly slipping all the way (200 ft driveway). As we're not blessed here with 'roundabouts I sort of did a California Stop at the end of the street. Wizzed around the neighborhood without letting the RPM's drop below 2000 and the clutch never disengauged (except, obviously, when shifting).

I never had an engagement problem, it pulled right in on shifts from 1-2 and 2-3 without any bars showing on the gauge. Actually, when she's cold, I'm real easy on the shifting and shift at low RPM's until she's warmed up. It's usually pretty lurchy (is that a word?) and bucks around some but she's always done that so I never paid it much attention. I've never done the 1/2 throttle, 5,000 RPM shift when she's cold (the butter smooth shift mode) so I don't know what that would do. I'll try that tomorrow if I get a chance.

I'm usually showing one bar by the time I leave the sub-division. That's a minute at most in the driveway and a 1/4 mile run to the main stop sign. How long does it take for your bike to hit the first bar?

If it's slipping above 1800 RPM after one bar is showing, you might have a YCCS problem.

Where's Ionbeam?

Interesting test.

Your heading off into the distance appears to be very different from mine, I usually start off in a city environment where speeds below 30 are the norm. If I start from cold, it takes a mile or so at these speeds to get a bar up (much longer in time than when idling in the drive), and with my '10, even greater distance for the idle rpm to return to normal. And, during this time, unless I keep in a lower gear than is necessary or desirable, the clutch is liable to be slipped.

I still have this feeling that the clutch engagement speed only comes down after the engine has been idling at its normal rpm with the bike stationary, I shall have to do some careful testing.

 

[BwanaDik]

OK, I just spent a weekend puttering around (500+ to the Hill Country) so had lots of time to think and observe. I'm mostly convinced that the YCCS cluth engagement mode is controlled somewhat from the regular engine management system. On ALL occations, the chutch engagement dropped into the "immediate engagement" or "normal engagement" mode once the first bar appeared on the display and usually before that. Can't tell as you can't see a 1/2 bar. Duh! :blink:

Anyway, I'm pretty well convinced that the YCCS has a link to the engine management system (re:coolant temp) such that, once beyond a certain temperature, the clutch engages in the "normal" mode and doesn't slip like crazy. At least that's what mine does. I have not observed anything that would link the clutch engagement RPM to whether or not it has returned to "normal" at temperature idle.

If your's continues to slip the clutch more than "usual" (mine engages almost "early" by some measures) once you've operated the engine more that a few minutes, I think you may have a YCCS problem.

BTW, I think mine works brilliantly as it's never stalled the engine and I've pressed it into service in almost all operational situations, from "just started" to "full hot" in a number of wrong gears (my fault) and road conditions (uphill/gravel). I've never had an issue!

 

[mcatrophy]

OK, I just spent a weekend puttering around (500+ to the Hill Country) so had lots of time to think and observe. I'm mostly convinced that the YCCS cluth engagement mode is controlled somewhat from the regular engine management system. On ALL occations, the chutch engagement dropped into the "immediate engagement" or "normal engagement" mode once the first bar appeared on the display and usually before that. Can't tell as you can't see a 1/2 bar. Duh! :blink:

Anyway, I'm pretty well convinced that the YCCS has a link to the engine management system (re:coolant temp) such that, once beyond a certain temperature, the clutch engages in the "normal" mode and doesn't slip like crazy. At least that's what mine does. I have not observed anything that would link the clutch engagement RPM to whether or not it has returned to "normal" at temperature idle.

If your's continues to slip the clutch more than "usual" (mine engages almost "early" by some measures) once you've operated the engine more that a few minutes, I think you may have a YCCS problem.

BTW, I think mine works brilliantly as it's never stalled the engine and I've pressed it into service in almost all operational situations, from "just started" to "full hot" in a number of wrong gears (my fault) and road conditions (uphill/gravel). I've never had an issue!

Thanks for taking the trouble to look at this.

My take on the control of the YCC-S is a little different from yours. Since my idle speed doesn't drop to the warm rate until there are 2 or 3 bars, it's just as well the engage speed doesn't drop after one bar, or the bike would be taking off under its own volition when the first bar showed

.

My '06 behaved much as yours, fast idle had gone when one bar appeared; I, like you, assumed it was simply the engine management telling the YCC-S that things were at "normal".

My '10 is definitely different in its warm-up characteristics, and the YCC-S seems to cope perfectly well, it just takes a long time to reduce the engagement/disengagement speeds to normal. After that, it behaves impeccably; as you say, you can attempt a move from rest in 5th gear and it won't stall (but doesn't accelerate all that well either

).

Although I am under the impression there are slight changes in its characteristics from the '06, I have no complaint at all in its normal operation, it flicks up and down the gears easily and smoothly, engages and disengages predictably and without any problem.

I'm going to try some warm-up experiments with mine as and when the opportunity allows.

Once again, thanks for looking.

 

[madmike2]

It's also possible that the YCCS reads the engine RPMs rather than the engine temperature. It seems more likely to me that the YCCS could adapt to the fast idle reading more readily than the engine temperature because it is probably already reading engine RPMs for clutch engagement at any given wheel speed (up-shift or down-shift).

If that's the case, the YCCS wouldn't "care" the engine temp, simply the idle speed to determine clutch application rate.

I'm just guessing as I an not an engineer (nor have I ever played one) and don't own an AE model.