GSXR1000K6 - Fuel Pressure And Flow Problems.

Modern thou's are a bit quick...
Even when they have fuelling issues. Ride this thing on the road and any problems are barely perceptible, but once on the track there's a gaping hole where power should be chiming in - and it's gutting! 

So I did a bit of investigating.
Ok, we start with an in-tank fuel filter/pump assembly. It consists of a gauze at the bottom of the unit to prevent any dirt entering the pump. The pump then forces fuel through another larger filter assembly, and the built-in regulator allows any excess pressure to vent fuel back into the tank. 
This complete unit supplies fuel, at 43psi, to a rail containing eight injectors - four primary and four secondary. The primaries maintain the low end of the engine's needs, with the secondaries starting to open at around 4,500RPM and their duration (time spent open) is controlled depending on the angle of the TPS (Throttle Position Sensor). Sounds easy enough so far.

Then there's the exhaust valve. With the standard can still fitted, I'm still relying on the actuator to open and close the butterfly valve in the pipe. A quick look through the frame at the actuator/motor, when switching the ignition on, and it's obvious it isn't moving through its complete cycle. Another problem?