Jerky throttle

[f2dz]

I've had this problem for a few months on my 2007 GSXR750 where the throttle is very jerky at certain RPMs.

It's worst in 2nd gear but it also occurs in all the others, it just lessens the higher you go - I guess due to the subsequent gears being taller and taller.

So when rolling off in 2nd gear the throttle just cuts when the bike passes 4k or so. It has done this as high as 6k but with a similar amount of rolloff in terms of the throttle position itself. It also abruptly comes on when accelerating once the throttle is in a similar position when getting on the gas.

I've done some reading on Suzuki forums and people suggest adjusting the throttle position sensor (TPS), which I have already done to no avail. My chain is also properly adjusted. Next I'm going to try reducing the amount of freeplay in the throttle cable itself but I may just be clutching at straws here.

People on those forums also talk about 'herky jerky throttle' which appears to be similar but also occurs at constant throttle at higher RPM. My bike only does it when decelerating and accelerating through this lower rev range of 4-6k.

Anyone else experienced anything like this?

[BuzzardNZ]

Try that ( TPS ) and get a TEKA tune to sort out the EFI.

Did the above on my SV and it sorted the problem out.

[caspernz]

My first question would be are the services up to date?

[ducatilover]

Could be as lean as fk. Air leak etc
Or your T/Bs are out of sync, because they do go out of syc ad is commonly overlooked

[f2dz]

Try that ( TPS ) and get a TEKA tune to sort out the EFI.

Did the above on my SV and it sorted the problem out.

I've adjusted the TPS already and it didn't help. Where did you get the TEKA tune done? I quickly searched up that there's a guy in Kumeu that can do em. Was yours expensive?


My first question would be are the services up to date?

Yes they are. It was last serviced within a couple thousand kms.


Could be as lean as fk. Air leak etc
Or your T/Bs are out of sync, because they do go out of syc ad is commonly overlooked

Hrm, I'll keep this in mind. Cheers.

[BuzzardNZ]

I've adjusted the TPS already and it didn't help. Where did you get the TEKA tune done? I quickly searched up that there's a guy in Kumeu that can do em. Was yours expensive?



Can't remember how much it cost, but if you are going to do the TEKA, you might want to consider after market pipes and an after market air-filter ( I got a BMC ) and get it dynoed and TEKA tune all in one go.

I got mine done at Wellington Motorcycles and was very pleased with the results. Felt like a different bike ( way better mid range power and smoother ) but fuel economy went way down.

[Stirts]

Your bike hates you...you should give it to me 308873

[kiwi-on-wheels]

I'd be looking at plugs coils etc, low rpm spark breakdown perhaps?

[eelracing]

I've had this problem for a few months on my 2007 GSXR750 where the throttle is very jerky at certain RPMs.

It'Next I'm going to try reducing the amount of freeplay in the throttle cable itself but I may just be clutching at straws here.

Anyone else experienced anything like this?

They all do it to some extent.Definately do the above and ride her higher up in the revs...sorted.

[Akzle]

well, since you've said chain...

carb choon.

[Big Dog]

Is this the stock air box and exhaust?


Stupid phone / Tapatalk, apologies in advance.

[Big Dog]

well, since you've said chain...

carb choon.

07 should be injected.




Stupid phone / Tapatalk, apologies in advance.

[nzspokes]

Is this the stock air box and exhaust?


Stupid phone / Tapatalk, apologies in advance.

The bike is stock. I have ridden it. Nice bit of kit.:niceone:

[Big Dog]

Filthy big dirty spot at the 5-7k mark variable on gear but repeatable on a stock bike would suggest a faulty / filthy O2 sensor or filter.

Less common would be a faulty / filthy fuel filter. Or the wrong fuel. Bus ran rough on anything other than 91 unless giving it a bit of open road.
The Hayabusa and the GSX1100 both would run rough as guts in spring if not serviced at 6k. Turns out the stock air box drains into a tube. That needs emptying after riding in heavy rain or change of season.


Stupid phone / Tapatalk, apologies in advance.

[mossy1200]

o2 sensor or exhaust sensor. You haven't plugged an exhaust sensor bypass plug on it by any chance.

[SVboy]

I've adjusted the TPS already and it didn't help. Where did you get the TEKA tune done? I quickly searched up that there's a guy in Kumeu that can do em. Was yours expensive?



Yes they are. It was last serviced within a couple thousand kms.



Hrm, I'll keep this in mind. Cheers.

Jerky jerky is usually tips, but you have done this. Side stand interlock switch can cut in if bike is ridden over harsh bumps. Possibly failing battery/ reg rec as this model are famed for it, and it can affect fueling. Fuel filter is in the tank, in two parts, a strainer, and filter which is integral with the pump and is non serviceable. Don't agree with a teka tune, what are they going to adjust? Are there any error codes when the bike is in dealer mode?

[f2dz]

I'd be looking at plugs coils etc, low rpm spark breakdown perhaps?

Plugs are new-ish, so shouldn't be that.


They all do it to some extent.Definately do the above and ride her higher up in the revs...sorted.

I usually only notice it when I'm riding to work splitting through traffic. I'm in 2nd gear the whole way and it usually sits around 4k. I could sit in 1st but it's too jerky for my liking at low speed.

I also don't notice it on the track unless it's a low speed corner, turn 5 at hampton for example. I've had the throttle jerk going through there in second and it's pretty unnerving.


They all do it to some extent.Definately do the above and ride her higher up in the revs...sorted.

It still does it when it's behaving right but it's only certain rides where it gets really, really bad. For instance, on my way to work this morning it was perfect. Still a little jerk through that rev range but it was 95% better.


Is this the stock air box and exhaust?

Exhaust is stock; guy mentioned that it had a K&N filter in it when I bought it but I haven't pulled the airbox open to check that. May have been BSing me, as he did that with other aspects of the bike before I bought it..


o2 sensor or exhaust sensor. You haven't plugged an exhaust sensor bypass plug on it by any chance.

Nope, but I have heard that the o2 sensor could be at fault. I'll have to look at my service manual to find out how I can check it..


Jerky jerky is usually tips, but you have done this. Side stand interlock switch can cut in if bike is ridden over harsh bumps. Possibly failing battery/ reg rec as this model are famed for it, and it can affect fueling. Fuel filter is in the tank, in two parts, a strainer, and filter which is integral with the pump and is non serviceable. Don't agree with a teka tune, what are they going to adjust? Are there any error codes when the bike is in dealer mode?

Yep, TPS is in the correct position. It doesn't cut out over harsh bumps - happens on perfectly flat highway all the time.

It's been doing this since at least October last year so if it were the battery/reg then I would have expected it to fail by now. I had a reg fail on my old Honda and that started acting up whilst I was riding it then completely died 10 minutes later.

I had to put it into dealer mode when I did the TPS adjust and there weren't any error codes. I'm hesitant to get a tune as I'm not planning on holding onto the bike much longer - I really just wanna try to sort it for an upcoming track day..!

[Big Dog]

K&N filters are pretty good but they need to be cleaned regularly to continue to be awesome. They claim to allow better airflow which affects the fuel air mix.
Most get the filter cans and power commander and then get the fuelling mapped to suit new airflow.

Probably a silly question but does your bike have modes? E.g sport, track, Eco? Does it do it in all modes?


Stupid phone / Tapatalk, apologies in advance.

[f2dz]

K&N filters are pretty good but they need to be cleaned regularly to continue to be awesome. They claim to allow better airflow which affects the fuel air mix.
Most get the filter cans and power commander and then get the fuelling mapped to suit new airflow.

Probably a silly question but does your bike have modes? E.g sport, track, Eco? Does it do it in all modes?

No modes. If it was the filter I would've expected it to have some consistency about it though..?

Small update - I did some quick reading and a guy recommended just turning the bike on for a few seconds before starting it, then waiting for it to fully finish its higher throttle idle before it goes to its normal idle (I'm sure there's a more technical term for this but I don't know what it is).

At least for the last couple days this has worked out for me. I've turned on the bike, left it for 10 seconds, then started it, left it for about 30-40 seconds, then ridden off. By comparison, I usually turn the bike on then instantly start it once the tach and dash lights have gone off - I then only wait a couple seconds for the idle throttle to dip to normal before riding off.

For whatever reason, so far over the last two days, waiting the extra time before riding has helped a lot. The jerky-ness hasn't been there at all for the last 125kms I've ridden. Touch wood, perhaps doing this is the fix but I have no idea why. Another forum I was reading suggested that waiting while it was only turned on helps to prime the fuel pump, but I'm not sure of the legitimacy of that..

[Big Dog]

A long time ago I worked at a car yard. You'd be surprised how many cars were running rough in the mid range. Most were fixed by taking out the aftermarket or very old element and putting in a new OEM one.

Any change to the flow can affect injection systems because they are programmed for the parameters expected with a stock filter, spark and exhaust.
If all else is ideal then the one small change may still be within the parameters. But if you already have sensors reading low because they are dirty you may find the engine running lean or overcompensating and running rich.

If following your procedure works for you there is no harm in battling on. Performance bikes can be a little black magic like that. The Hayabusa for example started a lot easier and ran cooler if verticaI when starting and leaned it to the right briefly before setting off. Something about wetting the moving parts not sat in oil on the side stand.


Stupid phone / Tapatalk, apologies in advance.

[f2dz]

A long time ago I worked at a car yard. You'd be surprised how many cars were running rough in the mid range. Most were fixed by taking out the aftermarket or very old element and putting in a new OEM one.

Any change to the flow can affect injection systems because they are programmed for the parameters expected with a stock filter, spark and exhaust.
If all else is ideal then the one small change may still be within the parameters. But if you already have sensors reading low because they are dirty you may find the engine running lean or overcompensating and running rich.

If following your procedure works for you there is no harm in battling on. Performance bikes can be a little black magic like that. The Hayabusa for example started a lot easier and ran cooler if verticaI when starting and leaned it to the right briefly before setting off. Something about wetting the moving parts not sat in oil on the side stand.


Stupid phone / Tapatalk, apologies in advance.

Good point, and somewhat comforting to hear it's not just me that has to worry about bikes playing up.

Like you say, no harm in continuing what I'm doing - easy enough to give the bike a bit of time before riding, just have to learn to be more patient!

[SVboy]

On all my GSXRs, I always let the dash cycle fully before starting, then let the bike warm until 50 degrees C.
Fuel flow issues, caused by a clogged fuel filter can cause issues. The 'tea bag' strainer can clog, but at least it can be removed and cleaned, unlike the fuel filter element. Flow rates can be checked, but if the problem is gone ATM, cool!

[f2dz]

On all my GSXRs, I always let the dash cycle fully before starting, then let the bike warm until 50 degrees C.
Fuel flow issues, caused by a clogged fuel filter can cause issues. The 'tea bag' strainer can clog, but at least it can be removed and cleaned, unlike the fuel filter element. Flow rates can be checked, but if the problem is gone ATM, cool!

Yup, gone for now. I'm happy to just assume it may be the problems you have mentioned but for now I'm happy to just ride. :Punk:

[biketimus_prime]

My Hyobag and old skylines were all the same. If I started them up from cold after sitting overnight and drove/rode they'd be jerky on the throttle or very flat and pick up extremely slowly until they were warmed up fully.
I now start my bike and put on my helmet, gloves etc and by then the idle has settled and she rides just fine. My carby bikes were never like that though.
Must just be how the EFI is when cold and running rich initially seeing as my cars did it too.

[nzspokes]

My Hyobag and old skylines were all the same. If I started them up from cold after sitting overnight and drove/rode they'd be jerky on the throttle or very flat and pick up extremely slowly until they were warmed up fully.
I now start my bike and put on my helmet, gloves etc and by then the idle has settled and she rides just fine. My carby bikes were never like that though.
Must just be how the EFI is when cold and running rich initially seeing as my cars did it too.

My neighbors wouldnt like that plan much at 6.30 each morning.

[breakaway]

One of my old GSXRs of similar vintage had been messed with extensively by a bunch of cowboys who thought they were experts on combustion engine theory. They removed the O2 sensor, changed the headers and can out with basically what was a straight through pipe, all on a road going bike that was already producing so much power most riders would have no hope of accessing.

The end result was a bike which idled roughly, was an absolute pain to ride below 4000 RPM. It ran fine above that.

So, what sort of "mods" does your machine have because the symptoms you describe sound eerily similar.

Either that or you're one of those nancies that can't get used to a sensitive throttle on a modern I4 that produces a shit ton of power (hint, it's supposed to be like that. That's part of the thrill.)

[F5 Dave]

K&n will affect the fueling. If you adjust for it fine. If you don't it could be lean which may manifest itself in different areas more noticeably. My SP lost almost 20 HP until after a week dyno'd it (had previous on same dyno ) and adjusted the jets. Riding it around I hadn't noticed I'm embarrassed to say. Same rules will apply for efi. The symptoms the stock bike has could be worse with more airflow.

[Pussy]

Not an uncommon problem with 06-07 GSX-R 600-750. Let the computer cycle before cranking (already mentioned), and reduce the cable free play. The E24 spec bikes fuel nicer than the US spec bikes that were brought in too.

[Ribit]

No modes. If it was the filter I would've expected it to have some consistency about it though..?

Small update - I did some quick reading and a guy recommended just turning the bike on for a few seconds before starting it, then waiting for it to fully finish its higher throttle idle before it goes to its normal idle (I'm sure there's a more technical term for this but I don't know what it is).

At least for the last couple days this has worked out for me. I've turned on the bike, left it for 10 seconds, then started it, left it for about 30-40 seconds, then ridden off. By comparison, I usually turn the bike on then instantly start it once the tach and dash lights have gone off - I then only wait a couple seconds for the idle throttle to dip to normal before riding off.

For whatever reason, so far over the last two days, waiting the extra time before riding has helped a lot. The jerky-ness hasn't been there at all for the last 125kms I've ridden. Touch wood, perhaps doing this is the fix but I have no idea why. Another forum I was reading suggested that waiting while it was only turned on helps to prime the fuel pump, but I'm not sure of the legitimacy of that..

I wonder if the Manifold air pressure sensor needs the extra time to get an accurate reading before you start it up...

[mossy1200]

One of my old GSXRs of similar vintage had been messed with extensively by a bunch of cowboys who thought they were experts on combustion engine theory. They removed the O2 sensor, changed the headers and can out with basically what was a straight through pipe, all on a road going bike that was already producing so much power most riders would have no hope of accessing.

The end result was a bike which idled roughly, was an absolute pain to ride below 4000 RPM. It ran fine above that.

So, what sort of "mods" does your machine have because the symptoms you describe sound eerily similar.

Either that or you're one of those nancies that can't get used to a sensitive throttle on a modern I4 that produces a shit ton of power (hint, it's supposed to be like that. That's part of the thrill.)

When I run my bike on race mod which I have programed to bypass o2 sensor and open stps early I get lower fuel economy and less throttle control at slower speeds.

[Pussy]

Only the Euro spec K6-K7s have O2 sensors. US an Aussie spec were sold here.

[Kendog]

My k7 750 had the same problem at random times, very frustrating and scary mid corner.
Adjusting the TPS and the slow start up process you described helped. But the problem never really went away.
Suzuki have not to my knowledge accepted this is a problem, despite the numerous people posting about it.

[f2dz]

My k7 750 had the same problem at random times, very frustrating and scary mid corner.
Adjusting the TPS and the slow start up process you described helped. But the problem never really went away.
Suzuki have not to my knowledge accepted this is a problem, despite the numerous people posting about it.

I still do feel the jerkyness some times but it's 95% better than the sudden lurching it used to do when I started it up quickly.

Looking forward to having it at the track sometime soon - like you say, mid corner it really is pretty scary/unnerving - and I had that happen to me most of my laps last time at Hamptons.