100% stock '09 lean running issues?


Hello gentlemen,
My recently acquired 4k mile '09 exhibits what I perceive to be CARB/DOT compliance tuning symptoms - more specifically a somewhat annoying fall-on-its-face between gear changes issue making seamless shifts frustratingly elusive. Depending on the degree of throttle opening, rev range and load where gear changes are made seems to be a factor. It just feels as if a slight fattening of the fuel map in conjunction with perhaps an ignition timing revision would cure the boggle. In steady state cruise conditions and roll-ons, regardless of gear position or road speed its faultless, no lean surge or hick-ups of any kind.

I'd like to keep it absolutely as OEM as possible, I.E. no piggy back devices. Even the exhaust system is perfect for my tastes as the quiet nature of the bike is a major plus so any modifications there wont happen.

Have any of you successfully remedied this boggle - perhaps a simple ECU re-flash would do? I thank you all in advance for any pertinent input.



Top Gun
Donating Member
Have the ecu flashed with Ecu Editor or Woolrich. It changes the ecu setiings without adding the likes of a PowerCommander(which can only adjust air/fuel). Nothing is added to the bike if you remove the ecu for a flash. If you want it flashed in the bike, or a Woolrich or Ecu Editor dyno tune, then you need to add a 2 wire jumper harness. It's almost invisible and goes between 2 empty pin locations on the black Yosh plug and the black ecu plug.
You can remove the 1st through 4th gear lower timing restrictions(and top speed limiter is automatically removed with this).
Copy/paste secondary throttle plate opening rates and stp fueling(not air/fuel) of 1st/5th to 2nd and 3rd.
This will really wake the bike up, very noticeably.
The gen2 Busa is also know to be on the lean side from the factory. A dyno tune is beneficial.
There are quiet and efficient aftermarket full dual exhausts too, like Akropovic. Or you could add a Vance&Hines ss universal header, it works with ALL mufflers, including stock. With it you can get rid of the catalytic converter, better flow and your feet will thank you, that thing will cook your feet.