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Hesitation/bog 2-2.5K RPM

9K views 102 replies 22 participants last post by  MrWilson 
#1 ·
Does anyone else feel like their bike is struggling 2-2.5k RPM? It goes from really struggling to...about to blast off at 3K RPM. With the throttle staying at the exact same spot. Notice every time I take off from a stop. It seems super touchy, goes from no throttle to riiiiiiiinnnngggg with like a mm of twist. Maybe it's just the break-in period and me keeping the revs low, but it is not smooth down low. Everywhere else, it's like butter. This is my first in-line 4 bike, is it normal?
 
#13 · (Edited)
Does anyone else feel like their bike is struggling 2-2.5k RPM? It goes from really struggling to...about to blast off at 3K RPM. With the throttle staying at the exact same spot.
Edit: I just came back from riding ... I let 6th gear wander down to 16 mph (1500 rpm?), and gave it full beans, I didn't noticing anything weird, it just pulls slowly but steadily, nothing odd. I thought it started to pick up a little around 4K myself.
 
#16 ·
I noticed it as well, and now that this discussion has been voiced by others, I definitely know it's there. Only in 1st gear pulling away from a dead stop - but that's really the only time the bike is ever below 2500 rpm. I've worked around this by just revving the engine a bit higher than that while letting the clutch out, just to avoid that bogging down. If the clutch is all the way out and you're giving it more throttle to get past the bog, and all of a sudden the car in front of you hits the brakes, could be a shitty situation.

Just slip the clutch a bit more to get going is my solution. Hopefully a flash would solve this, as I'm not sure if it's a fueling issue?
 
#17 ·
Another observation ... I don't know how to describe it, but I actually first noticed it from several online videos before we even got our bikes. What I noticed is that the sound of the rpms wasn't always a smooth increase, it sometimes sounds like a series of notchy incremental steps. Does that make sense? And I definitely get the same thing sometimes on my zx4rr. Doesn't happen on any other bike I have.
 
#18 ·
I noticed this too. Different from my Grom, R3, R7, and Bolt. Thought grom was the worst since the friction zone is almost with the clutch all the way out. But the take off from stop is different on this ZX4RR, it almost feels like I am about to stall on every dead stop take off. Is this a mapping ride by wire or inline 4 small displacement thing? Getting ready to send my ECU to 2wdw for a tune, hopefully their mapping does something to mitigate this.
 
#22 ·
Wondering if this is coded into the ECU as some sort of "clutch take-up assist auto-throttle". It kinda feels like that was Kawasaki's intention. If it goes away when KTRC is disabled that's another clue. If so I'd think it would be best addressed by something like a global enable/disable toggle instead of adjusting main AFR and timing tables. I'd also like to see this behavior disabled or removed when tuning is complete.

xorbe commented on a feeling of slight hesitation and surging at part throttle in the mid-range, around 6-10k rpm. I also feel this and getting it addressed is high on my priorities as well.
 
#27 · (Edited)
If you're in 1st gear and let it wander down to 6 mph / idle just barely coasting, and then hit the gas, I don't think the same hesitation is there.

It's subtle, but I think there's a difference from a dead stop? In Sport mode, there's that little lurch, but with KTRC off, the lurch is less and the initial really low power is just a bit more. I think. I tried a bunch of times. Annoying that Sport and Rider are at opposite ends of the selections, and it takes 2-3 seconds to pass through each mode.

xorbe commented on a feeling of slight hesitation and surging at part throttle in the mid-range, around 6-10k rpm. I also feel this and getting it addressed is high on my priorities as well.
I just watched vcyclenut's ecu deep dive yt video, and saw all those tables. As an EE/programmer ... I can already suggest multiple possible ECU reasons due to crap programming. But surely table driven engine smoothness was solved years ago.
 
#23 ·
Oh, THAT. Yes, I noticed it too. It's like no power the first second unless more revs and more clutch slip initially. Surely ECU games. Can't today, but tomorrow I'll try letting the rpms wander down really low in 1st and giving it gas, vs taking off from a stop in 1st.
 
#25 ·
Noticed this as well on the dyno every time I get going, so 1st gear. But why y'all riding at 2000 rpm?? You shouldn't be at such low RPM when you ride, so I don't really consider this an issue. That's like trying to drive a manual car at like 600 rpm...let me know how that goes! lol

This bike revs to over 15,000 rpm...you should pretty much never be below like 3500-4000 when riding.
 
#32 ·
Anyone else still noticing this? If so, with or without flash and which tuner?

i went for a 30 mile ride this morning and the hesitation from dead stop 1st gear take off is inconsistent. Some take offs are a lil less hesitation than others but still persistent.

I am getting used to it but revving higher makes it look like I want to race the car next to me during take offs. TIA
 
#37 ·
my tune does not have this, I had a customer here yesterday with another companies flash that did and it was eliminates with my flash. The other company is pushing this is a characteristic of the bike but its not, Its just a poor tune. Ive reflashed several now from that other company and all were fixed after my flash

I know I sound like a broken record but using a dyno designed for full throttle testing as the only way to tune the motorcycle is not the best way. My combination of street and dyno tuning eliminates these small throttle driveability issues you can get with just dyno tuning.
 
#38 ·
my tune does not have this, I had a customer here yesterday with another companies flash that did and it was eliminates with my flash. The other company is pushing this is a characteristic of the bike but its not, Its just a poor tune. Ive reflashed several now from that other company and all were fixed after my flash

I know I sound like a broken record but using a dyno designed for full throttle testing as the only way to tune the motorcycle is not the best way. My combination of street and dyno tuning eliminates these small throttle driveability issues you can get with just dyno tuning.
I can attest to the above. I have his flash and I have absolutely no bog or hesitation as described in this thread.
 
#40 ·
I thought the low power and torque in low rpm’s and the power in the higher rpm’s were just the nature of this beast. I’ve taken to riding it more like my old 2 stroke dirt bike that I used to have. That thing was gutless until you reached a certain rpm and then it took off. It was meant to be ridden in the high rpm’s, so I rode it that way. It was bright yellow and my mom said it sounded like an angry bumblebee.
 
#43 ·
I miss my old YZ80!!

im not saying my 4rr feels like my mt10 at the lower revs but you certainly dont have to change your riding style to enjoy the bike and dont have to ride around any bogs or hesitations

it will pull a high gear from a pretty surprisingly low rpm.
 
#45 ·
I miss my old YZ80!!

im not saying my 4rr feels like my mt10 at the lower revs but you certainly dont have to change your riding style to enjoy the bike and dont have to ride around any bogs or hesitations

it will pull a high gear from a pretty surprisingly low rpm.
My 1978 RM125 was fun to ride, but it was so old that every time I went for a ride I had to fix something. Parts were hard to find. I stopped riding it because of that. I ended up selling it to someone who raced vintage dirt bikes.
 
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#58 ·
To be honest and blunt about it , since my main mail in flash competitors are struggling with getting good throttle response in the bottom end I do not want to give up what changes I made that eliminated the poor stock throttle response and the bog.
 
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