according to the MCN article...

[zombieBUELLer]

"All Buell's air-cooled models, including the City X, all the XB12S motorcycles – the S, Ss, STT and Scg – and the XB12X Ulysses, get engine upgrades allowing them to rev 500rpm higher than the previous versions."

so my question is what did they "upgrade"?

 

[BuellPartsGuy]

New DDFI system for the ignition and the new crank sensor setup.

 

[BuellPartsGuy]

Did a little more research on it and this is exactly what I found on Buell's dealer site

2008 Buell XB models incorporate a new ECM and one-piece induction module that
utilizes an Idle Air Controller. This eliminates the manual Idle Speed Adjustment
Procedure and TPS Zero procedure. The replacement of the Cam Position Sensor by the
Crank Position Sensor eliminates the Timing Adjustment Procedure.

 

[zombieBUELLer]

thanks!