I rode my 07 ZX10R on the weekend and found that whenever I accelerated past 6000 rpm and back the throttle off, it maintained a partially open throttle and only slowly reduced rpm. This got pretty scary a few times heading into a corner expecting some engine braking and there was none. The interesting points about this behavior is that if I forced the throttle closed hard, it backed off. If I allowed the bike to slow gradually without forcing it and took my hand off the throttle, every time it hit 5,000 rpm's, without fail, it backed off suddenly and normally. All throttle operation below 5000 rpm is totally normal. Idle speed is also normal. This repeatable behavior has to be part of the clue, and makes me think the problem is electrical in nature.
I've recently fitted Helibars, new brake lines, and had just flashed (Woolich) my ECU to open the STP's much earlier and more aggressively than stock. It's running a KRTuned full exhaust system with no exhaust valve, and has a tuned PCIII.
I've checked the cables, routing and throttle operation, and all is normal.
I've reflashed the ECU back to factory to see if it fixes the problem, but don't know yet.
I've only had the bike for a couple of months, so can't say much about it's history. Can anyone give me any ideas as to why this might happen, or what else to check?

---

Just an update.
It seems from a very short ride that flashing back to factory removed the unwelcome partially open throttle lag. All I've changed was the point where the secondaries go wide open. What am I missing here?

* Last updated by: sweetfa65 on 7/14/2014 @ 1:08 AM *

---

This got pretty scary a few times heading into a corner expecting some engine braking and there was none.

See where this bike is?: before the apex, before the exit to accelerate, on lift. If there was engine braking, he'd be on his ass. Why? The wheel wants to lock or pulse under compression so it now upsets the chassis and comes around on you.

By mapping the 'run on' maps, [I made it up for the abstract], maybe that is what you felt? Throttle closed at a certain rpm may be one more safety valve? I'd have to ride the bike and meter up because I am stumped. Did we cut and paste what map to what? Or was this to grab blocks of cells and change the numbers but stop at 6k?

---

Hub, I get what you're saying about chopping the throttle. It wasn't like that. It was like the throttle was still accelerating, or only barely closing. I had to brake twice as hard as usual to try to slow the engine down, to stop being propelled past the corner. On this flash, all I did was to change the STP map to open the secondaries more aggressively, like fully open at about 3000 rpm and minimal throttle opening. Nothing else. I think I copied the STP numbers from one of my 14R maps, and pasted the numbers into the 10R map.

---

I think I copied the STP numbers from one of my 14R maps, and pasted the numbers into the 10R map.

Too 'run on' rich? Is that in fuel feed or sub's not closing on a faster guillotine move? Then it asks:

2006 - 440cc injectors
2008 - 330cc injectors

14R - ???cc injectors
10R - Same body as the 14R

See that one variable about a fuel change between map and injector size?
See also where both have different power curves?
See where one bike may rev higher than the more torquier bigger bore size?
See where this needs an AFR/Sub/Ign cameras on each one?
See also where one may have more mode switching than the other?
See where a few years may not apply to the less mode'd bike?
See also if the members or Justin might take a crack at this. All I'll do is take wild binary guesses at it.

* Last updated by: Hub on 7/14/2014 @ 9:12 PM *

---

Yeh, I see what you're saying/asking Hub. In looking at both bikes maps, they behave very differently. The only move I'm made on the 10R though is in dictating a more aggressive STP opening profile. Earlier in RPM, and earlier in throttle %. Not full on really early though. I did just notice that the 10R has some very peculiar fuel trim (by gear #) and exhaust valve maps, which are nothing like the 14R. The 10R has no valve, but the motor's still there. I almost wonder if the PC III and exhaust valve servo are messing with the ECU. Hmmm. Wonder if Justin & Co might have an insight as to what's going on inside there.

---

The only move I'm made on the 10R though is in dictating a more aggressive STP opening profile.

You'll have to hand carve that curve by trial and error.

I did just notice that the 10R has some very peculiar fuel trim (by gear #) and exhaust valve maps, which are nothing like the 14R.

You've got my attention. And there you go. Gear I sort of understand. Ex valve maps is a new one on me. Maybe it's time to read a brochure or read a shop manual.

The 10R has no valve, but the motor's still there.

I'll assume the flies are out and the actuator is still working.

I almost wonder if the PC III and exhaust valve servo are messing with the ECU.

No. The EVS follows throttle and rpm. PC receives the analog output. This helps clear a lot of the diagnosing if you think like this:

Analog: is like a dimmer switch light. It can create bright and dim light so that means more than one or 'analog means many.' Look at how the throttle position sensor sends in many openings so a sensor sends out many signals.

Digital: is how you look at the ECU. Each component on that motherboard means a diode, resistor, transistor, or more like, it has one number or a resistance number. So look at digital as meaning one number.

Analog: is what is being sent back out from the ECU. It tells the actuator or the stepper motor or the 'motor' as you call it: what position to be in on lift/WOT/etc vs. throttle position. This can move in many positions so we are right back to where we started as in an analog signal enters first.

PC III: is what? A non-moving box with diodes/resistors/etc., just like the ECU is filled with resistors, diodes, etc. This box is in the middle of the ECU sending out an analog number to the sensor/motor/injector, etc. Here's where you put the steps all together...

Analog = What was the ECU waiting for? An analog signal.
Digital = What entered into the ECU? The analog signal.
ECU = What did the ECU calc? The various values being sent out to certain component demands as an analog signal.
PC III =What signal was picked up again out of the ECU? The analog signal.

Said another way:
Analog = sensor
Digital = ECU
Analog = The wire out the ECU
Digital = The PC captures the analog signal.
Analog = The PC sends out the analog number AFTER the ECU's original calc.

Said another way:
1 = On
0 = Off
1 = On
0 = Off

Said another way:
No, no interference. Look how the ECU already calc'd out the analog signal BEFORE exiting the ECU. Therefore, the calc does not interfere with the PC interfering with the entry side. The exit side has been caputured in other words. No PC is capturing the first analog going in. The PC is not an analog unit. It is a digital unit to send an analog signal. It captures that analog signal out from the ECU. You have to look at all this in steps needed to see the PC Cannot be part of the problem as you surmise.

Hmmm. Wonder if Justin & Co might have an insight as to what's going on inside there.

Most likely.

* Last updated by: Hub on 7/15/2014 @ 5:34 AM *

---

Yes Hub. This first pass seems to be part of the error part so far.
I like the way you explained the dif between the analog and digital inputs. That actually makes sense, and takes some of the "black magic" out of it. Cause and effect, ECU looking for specific inputs then new signal out, right? I'm a little like you in that I'm like a cat with a mouse until I understand. I NEED to know HOW to fix something, but I LIKE to know WHY.

Ex valve maps is a new one on me.

The 10R has a butterfly valve in the rear of the exhaust mid-pipe that restricts the flow of exhaust. Everyone takes these out and leaves the servo motor in place. Mine has a KR Tuned full system, so no valve. The actuator motor is there and still operates. An eliminator made up of resistors can be put in-line to get rid of it and stop the fault codes that result from its removal. There is a separate map in the ECU to control how this thing operates. It ranges from 29.9% to 99.8% open. I'm not sure what the function of the exhaust valve is. Curiously the percentage increases after 6500 rpm. Hmmm.

I'll assume the flies are out and the actuator is still working.

See above. I'm unsure if it still has the STP's (flies) in place. I'll confirm that when I next service. Gauging how the bike has been handled in the past, I would doubt if the flies are removed.
The map I changed had no changes to the lower 3 columns (under 2.9%) of throttle percentage and only increased gradually above 2000 rpm. That shouldn't have any effect at the 0% closed throttle position, should it?
The fuel trim changes in each gear too. All at 100% up to 6500rpm, then 1st gear trims down to 92% at 12,000rpm, and each gear raises incrementally up to 6th gear which is at 100% all the way through. There's that 6500rpm marker again???
I know it's probably easier for me, cause I can see the maps in front of me.

---

Oddly enough...you said you added Helibars.I know you said you 'went back to stock mapping' and it eliminated this deal.Is it possible the return spring is weaked or something?And the helibars...you didn't somehow not realizing that you MAYB kinked your throttle line along the way????Just throwin that out here.It's sounds like a weak return spring.OR,the bar end is rubbing on the grip?I do believe the grip moves OUTWARD a few cc's when adding throttle.Perhaps that's why it frees up at that lower rpm.