Flat Acceleration

[philthyphil]

So I posted about this a couple months ago just after I installed the Akrapovic Carbon and flashed ECU on my FZ 07. I didn't really see it as a problem at first, but now it happens in ways which bother me and just doesn't feel right. If I'm on the freeway, in 6th gear going 70ish mph, with the engine at about 5000 rpm and I increase the throttle I can hear the rpm raising, but for a second or so the bike doesn't really pick up speed, and then all of the sudden it kicks in and goes. It almost feels like the clutch is slipping, but I don't think that it is. It is just like a delay in the power delivery. And the weird thing about it is that I can't really reproduce this all the time. Sometimes under the same conditions, going the same speed and rpm, I'll gas the bike and there will be no delay. Has anyone else experienced this, and is there anyway to remedy it? I never noticed this happening until after installing the Akrapovic and flashed ECU. 

[norcal616]

A few guess are
 
My best guess is, its depends on how hard you hit the gas, I know ECO mode is still lit on up the dash at 70mph...ECO mode has a few built in fuel maps ?(in my opinion ECO mode should be made to walk the plank into the deepest trench in the ocean ? ) so it's possible you are noticing the fueling change between ECO mode and non ECO mode...I see it all the time on my AFR meter and can feel the stubble diffrence in fueling...
 
To be sure check to see if it's nothing mechanical like cable slack, TB synch, dirty/plugged up airbox, check to make sure airbox is drained of any water or oil, when was the last time you did spark plugs, safety connections, suspension, etc...
 
 
 

[philthyphil]

A few guess are 
My best guess is, its depends on how hard you hit the gas, I know ECO mode is still lit on up the dash at 70mph...ECO mode has a few built in fuel maps ?(in my opinion ECO mode should be made to walk the plank into the deepest trench in the ocean ? ) so it's possible you are noticing the fueling change between ECO mode and non ECO mode...I see it all the time on my AFR meter and can feel the stubble diffrence in fueling...
 
To be sure check to see if it's nothing mechanical like cable slack, TB synch, dirty/plugged up airbox, check to make sure airbox is drained of any water or oil, when was the last time you did spark plugs, safety connections, suspension, etc...
 
 

Interesting, I had no idea that eco mode did anything to the fuel map. I always just thought it was like a little indicator that you're riding style at that moment is conducive to good fuel mileage. Now that you mention it, I believe that I am generally in eco mode when this is happening, so that could be it. Thanks for that info! 
As far as cable slack, I think I'm good. The throttle has very very little play in it. It is about within spec. I only have 4000 miles on the bike so I'm not up for spark plugs just yet. I have not done the throttle body sync yet. I did pick up a carbsync gauge so I'll probably check the TB sync next time I service the bike. I had a look down in the air filter about a thousand miles ago, and all looked good inside there then, and I was experiencing the described problem at that time too.  

[pineappleunderthesea]

I have the same issue, and I'm pretty sure it's the flash: my stock bike didn't do it. With the Akra Carbon and no flash it didn't do it. With the flash it did it.
 
I run with the snorkel out, not sure if in or out would matter in terms of the hesitation. I've also had the TB synced, no change. I got used to it over time, I just give it more gas to get it out of that "limp mode". But yeah, I've wondered at times if they gave us the wrong flash (the Akra Ti flash), or if some bikes are more sensitive. I've never called 2WDW about it, but it doesn't really bother me anymore, but I could see how it could be annoying if you're looking for perfection. I guess if you could log what the ECU is outputting like you can with a OBD-II port and send it to 2WDW...
 
 

[ddog]

I have the same setup, akra carbon and 2WDW ecu flash, and I have not experienced this issue as far as I know. I'll try to keep it in mind next time I ride to make sure.

[rick]

You say you can hear the revs going up, but are your RPMs actually rising or are you just hearing the motor working harder with the throttle getting opened? Cause if the RPMs are climbing and the bike is not accelerating, then your clutch really is slipping.
 
Gonna assume yer using a motorcycle specific oil? Do you do a lot of hot starts with revs up? Glazed clutch plates or too many friction modifiers in more car-friendly oil can cause clutch slipping.

[philthyphil]

You say you can hear the revs going up, but are your RPMs actually rising or are you just hearing the motor working harder with the throttle getting opened? Cause if the RPMs are climbing and the bike is not accelerating, then your clutch really is slipping.  
Gonna assume yer using a motorcycle specific oil? Do you do a lot of hot starts with revs up? Glazed clutch plates or too many friction modifiers in more car-friendly oil can cause clutch slipping.

Yea, I'm using 10w40 Mobile One 4t motorcycle oil. The RPMs are going up, and the bike does accelerate, but it's very non-linear. It's like around 5000 rmp the bike just starts to haul ass, and before 5000 rmp the acceleration is very sluggish. This doesn't happen consistently.  
I don't think it is a clutch issue because my clutch is still very grabby when taking off from a stop, and doesn't seem to give me any indication of slippage. I really think it is a fueling issue. I may try getting in contact with Mel at 2wheeldynoworks and see if he has any suggestions. 

[philthyphil]

I have the same issue, and I'm pretty sure it's the flash: my stock bike didn't do it. With the Akra Carbon and no flash it didn't do it. With the flash it did it.  
I run with the snorkel out, not sure if in or out would matter in terms of the hesitation. I've also had the TB synced, no change. I got used to it over time, I just give it more gas to get it out of that "limp mode". But yeah, I've wondered at times if they gave us the wrong flash (the Akra Ti flash), or if some bikes are more sensitive. I've never called 2WDW about it, but it doesn't really bother me anymore, but I could see how it could be annoying if you're looking for perfection. I guess if you could log what the ECU is outputting like you can with a OBD-II port and send it to 2WDW...
 

I run mine with the snorkel out as well. It sounds like we have identical setups. Someone posted earlier in this thread that it may have something to do with eco mode. I think it is definitely a fueling problem that is tied to the ECU. 

[rick]

You say you can hear the revs going up, but are your RPMs actually rising or are you just hearing the motor working harder with the throttle getting opened? Cause if the RPMs are climbing and the bike is not accelerating, then your clutch really is slipping.  
Gonna assume yer using a motorcycle specific oil? Do you do a lot of hot starts with revs up? Glazed clutch plates or too many friction modifiers in more car-friendly oil can cause clutch slipping.

Yea, I'm using 10w40 Mobile One 4t motorcycle oil. The RPMs are going up, and the bike does accelerate, but it's very non-linear. It's like around 5000 rmp the bike just starts to haul ass, and before 5000 rmp the acceleration is very sluggish. This doesn't happen consistently.  
I don't think it is a clutch issue because my clutch is still very grabby when taking off from a stop, and doesn't seem to give me any indication of slippage. I really think it is a fueling issue. I may try getting in contact with Mel at 2wheeldynoworks and see if he has any suggestions. 

If the tranny was in 4th or 5th gear, would it still feel the same? 
 
My Aprilia has twice the HP and 50% more torque than the FZ. It's also geared taller so runs a full gear lower all the time. It'll run a bit over 4k at 70 mph in 6th gear. But I won't even put it into 6th until it's doing at least 70 cause the motor feels like it's being lugged - it's not, it just feels sluggish. So I do most of my riding in 3rd thru 5th gear on that bike until speeds get well up - it'll do a legit 150 mph.
 
i think what yer experiencing is the same thing. Maybe the pipe and other stuff is accentuating this. Others with the same set-up will have different ride styles that might not result in an issue. Even your weight will influence this - put a passenger on the back and I'll bet this gets far worse. Simple solution is is to downshift and just run another 1k revs. You'll have plenty of power. 
 
As for Eco mode - the dash indicator is only telling you that the throttle opening is small - something like 15% or less. Sure there's a map involved - the O2 sensor is likely inputting at those throttle settings as well. But I don't think "eco mode" is special to this or any vehicle. The dash is just telling you you are using less fuel when it's lit  

[philthyphil]

Yea, I'm using 10w40 Mobile One 4t motorcycle oil. The RPMs are going up, and the bike does accelerate, but it's very non-linear. It's like around 5000 rmp the bike just starts to haul ass, and before 5000 rmp the acceleration is very sluggish. This doesn't happen consistently.  
I don't think it is a clutch issue because my clutch is still very grabby when taking off from a stop, and doesn't seem to give me any indication of slippage. I really think it is a fueling issue. I may try getting in contact with Mel at 2wheeldynoworks and see if he has any suggestions. 

If the tranny was in 4th or 5th gear, would it still feel the same?  
My Aprilia has twice the HP and 50% more torque than the FZ. It's also geared taller so runs a full gear lower all the time. It'll run a bit over 4k at 70 mph in 6th gear. But I won't even put it into 6th until it's doing at least 70 cause the motor feels like it's being lugged - it's not, it just feels sluggish. So I do most of my riding in 3rd thru 5th gear on that bike until speeds get well up - it'll do a legit 150 mph.
 
i think what yer experiencing is the same thing. Maybe the pipe and other stuff is accentuating this. Others with the same set-up will have different ride styles that might not result in an issue. Even your weight will influence this - put a passenger on the back and I'll bet this gets far worse. Simple solution is is to downshift and just run another 1k revs. You'll have plenty of power. 
 
As for Eco mode - the dash indicator is only telling you that the throttle opening is small - something like 15% or less. Sure there's a map involved - the O2 sensor is likely inputting at those throttle settings as well. But I don't think "eco mode" is special to this or any vehicle. The dash is just telling you you are using less fuel when it's lit  

 
Cool, thanks for the pointers. I was kind of thinking that the lugging issue may have been a possibility, because it does happen when the bike is at a lower RMP in 5th or 6th. It doesn't ever sound like the engine is lugging or anything though. From my own testing and experimenting so far, dropping it down a gear and then applying throttle does seem to offer a remedy thus far. It's just weird when I'm cruising along at 70 in 6th gear, then engine doesn't seem to be lugging, and then when I apply throttle without downshifting there is a major delay, and then all of the sudden all of the power just arrives and the bike goes like a bat out of hell. It just doesn't feel right. I'm hoping your right, and it is just something that I'll have to adjust for with my riding style... thanks again for your input, I appreciate it.
 

[rick]

Your pipe might have caused a bit of a flat spot in the torque curve. Though the reflash should have taken care of it, w/o putting it on a dyno, there's no good way to know, beyond yer perception. . And even though there are bikes with the same set up and flash as yours, I'll suggest that no 2 motors/FI systems are exactly the same, so yours might still need some custom massaging.

[peteinpa]

Just to cover all bases, might want to check that air filter again. Might be critters, a rag you keep under your seat, dirty air filter, etc.

[rosseric]

Finally! I've posted in other sections of this forum in the past about this and no one has ever replied to my inquiry on this exact issue. I run a PC V,DNA filter w/o snorkel and Akrap Carbon. I took it in to my local dyno shop and according to the readout everything came back fine but I was still having this issue, though it did help a bit. The store owner said modern bikes come from the factory with sections of their ECU that can not be manipulated. I forget the exact wording he used but something about a closed-loop? This is my first bike so I'm still learning all the jargon.

[stickshift]

The store owner said modern bikes come from the factory with sections of their ECU that can not be manipulated. I forget the exact wording he used but something about a closed-loop? This is my first bike so I'm still learning all the jargon.

When the 'eco' mode displays on the dash the efi is running in closed-loop mode, i.e. using the o2 sensor reading to adjust fuelling. 
I have a ti akra, PCV (dynojet map 22-065-006), snorkel left in. My PCV uses the 'o2 optimizer'; this plugs in line into the standard o2 sensor plug - I have no idea how it changes the standard 02 values, but worth checking that you have this part if the issues are related to transition from closed-loop operation.
 
I've never experienced anything like what's described above.
 
A dyno run may not pick up these issues, particularly only if wide open throttle run is done to check fuelling.
 
 
 

[rick]

Yep, my understanding as well - the eco light is an indicator that the ecu is in a "closed loop" map and the O2 sensor is feeding back mixture info (from the exhaust gases) to the ecu to help keep the motor running as lean as is possibly safe. This helps keep fuel economy up and emissions down. It also only happens at happens at small throttle openings - cruising along below 5-ish k RPM - so the TPS is in play as well. .
 
That optimizer, if I understand correctly, bypasses the O2 sensor and somehow fools the ecu into thinking the throttle is open more - so there's no error codes popping up. The motor now runs in "open loop" all the time. This i how my old Aprilia runs as there's no O2 sensor. The map now has to be pretty much perfect to allow decent fuel economy as well as fueling.
 
this little confusion lets the motor run off of a custom made map ("flash" if you will) through the entire rev range.
 
So, you might just be experiencing where the motor is switching from closed to open loop and feeling that small amount of time in the transition as a flat spot. Your ride style, your weight, and you might just be very sensitive to feeling it, will play into it.
 

[Beemer]

I've felt this on my bike from time to time and I just figured that's what the bike does by design, that nothing is wrong. I like to pretend it's just turbo lag and smile when my arms straighten and my head snaps back a little.