We recommend the X14iED for general use on all Sportsters. This provides the best all around performance.
For Riders that want to experiment with fuel mixtures, the VIED allows a range of fuel mixtures from 14.3 to 13.7:1. This is our recommend alternative to the X14ED. It gives you the chance to try the 14.0:1 and 13.8:1 AFR's, making the final setting based on your riding style.
For Riders with a Bar Hopper riding style (in town), the XiED can be used. Its slightly richer fuel mixture than the X14iED is well suited for in-town riding, but not high RPM, high speed riding.
Contrary to popular belief, richer is not alway better, only richer. For normal cruising in closed loop, there is a diminishing return as the fuel ratio gets richer than 14.2:1. The X14iED is set at 14.0:1 which as proven to be an excellent all around fuel mixture, especially when taking into account the adaptive nature of the HD Delphi ECM.
A technical update.
The 2012 XL's , especially the 883, seem to do a bit better with the XIED's.
HD has changed the fuel maps due to emissions regulations. This has resulted in the 2012 sportsters really liking the extra 2% fuel the XIED provides over the X14iED.
Not that any of the 2012 XL's will run bad with the X14's, they just respond better to the slightly richer XiED's.
This will apply to the 2013's if they use the same Bosch O2 sensor.