Just thought I'd pass on some info on my experience trying to fix this aggravating surge and loss of power/hesitation at around 4500RPM on my 2004 VFR. I tried every thing: synch the starter valves, block the pair valves, eliminate the O2 sensors - none of that had any effect at all! I broke down and bought the turbo city fuel pressure regulator and installed it. As advertised my bike is now fixed and I couldn't be happier! Runs like a dream and is a joy to ride now! Here is a link for those who may be interested: Turbo City - Rock-It Parts
Witch one? I changed mine last year at dealer for 500$ with diagnosis.... seems starting to do the same again
