Excerpted from another post I wrote a while ago:
My take:
Surging: At a steady throttle, light engine load, the engine speed varies a small amount which feels like the throttle is being opened and closed a tiny amount even though it is being held steady.
Abrupt power delivery: When the throttle is closed the engine goes into a decel FI routine where fuel injection is basically turned off, then when power is asked for again there may be small hesitation without response as the throttle is rolled on, then suddenly you get all the throttle that you dialed up. Addressed by a PCIII.
Abrupt Throttle Response II: The Gen II throttle cam is eccentric (not round) causing the throttle to respond in greater proportion than what the operator intended. The steep ramp of the throttle cam is right around the 3k rpm range. A second issue are the gorilla springs on the throttle pulley making it very tiring to use and makes fine throttle control difficult. A G2 throttle tube & cam will neutralize the eccentric throttle cam. Some people acknowledge the risks and partially unwind the throttle springs to lighten up response.
