2004 fuel flow issues


Hey everyone,

I bought an '04 Busa earlier in the year with 75K miles on it to use as my street bike. It needed some love at first and wouldn't rev past 8K @ WOT. I measured the fuel flow per the service manual and got 200ml/30sec.
So I have since:
-Replaced the injectors with some fresh RC-cleaned OEMs
-Replaced the ecu with my street flashed unit
-Cleaned the fuel line and rail
-Replaced the fuel pump with a known good pump from an '07 with a clean strainer
-Cleaned and lubed the FPR, and zip-tied it to the pump assembly for added insurance (press. measured at 48psi)
-Cleaned and inspected the fuel pump assembly housing.
I've now got the flow at 600ml/30sec which is still half of where it should be (1,200ml/30sec). It finally revs to the limiter, but is definitely losing power at the top end (probably lean).

Any ideas on what still might be the problem? My next move is to just buy a Walbro / Bosch intank pump, but trying to keep the costs down on this bike so I have more funds for the race bike.

Also, I noticed that the Walbro pump specifically for this bike requires some "modification" to make it work right. What modifications are necessary for this?

Well i didnt see this in your list .. Is the lining peeling in the tank any did u check and clean the petcock ?