Bike stuttering at 6000 rpm

[Big ted]

I love and hate this bike
New fuel pump tps spark plugs pairs removed still having issues at high revs
Sometimes it clears and red lines but mostly bottles out at 6000
Got fault code once c28 but not had f1 light flash since any ideas guys please as summer almost over now

[Snapey]

You say a new fuel pump was fitted but did you also replace the high pressure filter? Sounds to me like fuel starvation at high revs so maybe it's time for a filter flush or better still a filter bypass.

[Big ted]

Filter bypassed mate
It is also running rich end can black so not looking like lack of fuel.
Its crazy it sometimes rides through it and feels like im sat on a rocket but most times hits 6k and wont pull past it.
Tried standard pump and higher pressure pump. New fuel lines all injectors cleaned and serviced new plugs rectifier battery pairs removed tps etc.
Running much better but not 100% as yet and driving me crazy

[KiwiCol]

Your bypass isnt blocked is it? or too fine a micron?    How about testing flow rate & pressure after the filter?   Gotta be 'the next step, yeah?

[grog]

Ted, sounds like youve done all the logical stuff. Maybe the secondary butterflies sticking, not always opening. Should throw a F1 but strange things happen.

[Hooli]

Your bypass isnt blocked is it? or too fine a micron?    How about testing flow rate & pressure after the filter?   Gotta be 'the next step, yeah?

That'd be my thought too. It does sound like a blocked high pressure filter so I'd want to check the output from your system to see if it's what the bike is expecting.

It could be a high pressure pump is keeping the fuel rail at too high a pressure. The ECU controls the fuel by how long the injectors are open, if they are running a higher fuel pressure then the bike will be running rich.

[Blubber]

Ted, sounds like youve done all the logical stuff. Maybe the secondary butterflies sticking, not always opening. Should throw a F1 but strange things happen.

From memory... around 6.000rpm the STV should actuate to fully open.

Sounds feasable

[Eric GSX1400K3]

Remember that 1 and 2 are not directly connected by the same rod to 3 and 4 on both primary and secondary control valves.  There's an adjuster screw between 2 and 3.  I found on mine that the STPS was reading differently between 1-2 and 3-4 when balancing the throttle bodies, I believe that there's probably a tolerance range between the two banks that the ecu can handle, but if this is too far out between them, you may have fuelling issues at higher rpm as the secondaries are fully open (or trying to be) and the ecu is trying to calculate what fuelling to provide.   I recall my stps was reading 5-10 ohm different depending on which pair of secondary butterflies I opened.  You can adjust between the two to ensure you get the same resistance.

[Big ted]

I'll check that now
It sounds like a plan to me mate thank you

[Big ted]

I did all as mentioned checked charging system making sure i had good spark and good fueling.
Cut my rear can in half to help the motor breath. This helped massivly it revs to apx 7k
I even used spray carb cleaner into air filter when revving and got total red line.
Lack of fuel. Powercommander fitted and taken to malton for dyno. It was running very lean even though tail pipe was black. Mixture was all over the place now after i balanced injectors and had mixture sorted it runs like a good one. If i red line it i could take revs off the clock not that i intend to at all. This issue was down to suzuki the bikes are great but have too many sensors that can work against each other.
John at malton set up my fueling and im more than happy at the outcome.