07 gsxr 750 2ndary butterfly removal

[Fencer]

Here is the answer to the age old question

I pulled the 2ndaries to get rid of the herky jerky throttle response on the bike. it worked for that:up:

I drilled them out of the rail. The rail is still in the bike, the servo is still active so No FI codes to deal with or jumpers to disable. In other words, the bike thinks they are still there.

The bike was custom tuned prior to the removal and re-tuned after the removal, by the same tuner on the same machine.

Here is a plug for Wayne at Power-Tripp performance:beer:

The yellow line is before removal, the blue line is after removal.

As you can see there is a drop in power and torque from 4-8k the performance is identical (lines overlay each other) in all other RPMs

the worst drop is maybe 4 hp and 2.5 lbs or Tq. To get rid of the jerky throttle response it is worth it to me.

P.S. Wayne played with the mapping in this area to see if he could make any gains. In the end, we stayed with the map from the pre-removal period as all other changes were detrimental to performance

 

[HighWay]

The herky jerky throttle has been described so many ways that it gets confusing. What was your bike doing?

I'm chasing a problem at the moment that is a delayed throttle/hesitation. The throttle response is like a light switch. Close the throttle for corner entry and when you go to pick the throttle back up it hesitates and then just snaps on. Once you get past this point you can modulate the throttle smoothly, this just happens when you completely close the throttle then try to add power. I have thrown the usual tune up parts at it with no change and have just picked up another set of throttle bodies to try.

 

[Fencer]

My issue, and my understanding of others description of the herky Jerky is that the throttle is either ON or off. there is no modulation of the throttle, it gets to a certain point and just chops off making it unpleasant to control in corners.

I don't recall reading anyone describing it as a hesitation, although one may interpret it that way.

 

[HighWay]

Fencer;204536 wrote: the throttle is either ON or off. there is no modulation of the throttle, it gets to a certain point and just chops off making it unpleasant to control in corners.

Exactly what mine is doing. Thanks

 

[zstylem86]

so after last month's track day, i began experiencing a really sketchy throttle control/response. example, i feel my bike and myself jerk and bobble when getting on the throttle out of a turn (no matter how smooth i am). feels like it goes from 0 throttle to full throttle instantaneously.

i removed the complete SET valve prior to last track day and i'm not sure if that contributed to the problem. regardless, i've been reading up on which sensor or valves to adjust/remove that its getting annoying just trying to keep up with all the acronyms.

SET valve ? - i doubt this was the culprit, but i scrapped mine.
TPS - when in dealer mode, my bikes checks in at -COO so i don't think there's much to adjust. but i can double check with a voltmeter
STVA - i'd be a little worried drilling this completely out, maybe a last resort.

Other minor changes I can make besides anything electrical...

Tighten chain - maybe there was too much slack
Replace throttle tube with a quick turn
Increase the idle screw - might help with bogging and make decel less harsh

but that's all i have right now. this is really bothering me as i believe this should never be an issue on these types of bikes and its all too common. its not much to ask for smooth throttle response on a sportbike.

 

[HighWay]

zstylem86;208359 wrote: so after last month's track day, i began experiencing a really sketchy throttle control/response. example, i feel my bike and myself jerk and bobble when getting on the throttle out of a turn (no matter how smooth i am). feels like it goes from 0 throttle to full throttle instantaneously.

i removed the complete SET valve prior to last track day and i'm not sure if that contributed to the problem. regardless, i've been reading up on which sensor or valves to adjust/remove that its getting annoying just trying to keep up with all the acronyms.

SET valve ? - i doubt this was the culprit, but i scrapped mine.
TPS - when in dealer mode, my bikes checks in at -COO so i don't think there's much to adjust. but i can double check with a voltmeter
STVA - i'd be a little worried drilling this completely out, maybe a last resort.

Other minor changes I can make besides anything electrical...

Tighten chain - maybe there was too much slack
Replace throttle tube with a quick turn
Increase the idle screw - might help with bogging and make decel less harsh

but that's all i have right now. this is really bothering me as i believe this should never be an issue on these types of bikes and its all too common. its not much to ask for smooth throttle response on a sportbike.

Just remove the secondary butterflies. Two phillip screws hold the plates on and they can be removed/replaced easily if need be. I removed mine before VIR last weekend and it completely solved my problem.

 

[zstylem86]

HighWay;208397 wrote: Just remove the secondary butterflies. Two phillip screws hold the plates on and they can be removed/replaced easily if need be. I removed mine before VIR last weekend and it completely solved my problem.

did you notice any difference in the air/fuel mixture? i've heard removing the secondary butterflies can cause the bike to run lean.

and did you just remove the plates?

 

[HighWay]

zstylem86;208485 wrote: did you notice any difference in the air/fuel mixture? i've heard removing the secondary butterflies can cause the bike to run lean.

and did you just remove the plates?

I plan to have th bike tuned this winter so I will know then for sure but the seat of the pants dyno didn't notice any lack of power or a lean condition. Bike ran the same temps, no glowing red headers, just a nice smooth throttle.


I just unscrewed the plates and slide them out leaving everything else. The ECU still thinks they are there so no FI light.