I am having a bit of a problem with my Vulcan 900. As stated in another post, I debaffled my stock pipes and I lost some power. There has been alot of people that have stated on this site in many different threads that the Vulcan's tend to run rich from the factory. So I wanted to see how rich they really ran. I took my A/F ratio sensor tunning tool that I have and slid it up the pipe for some readings. On cold start, it was 13.5:1. When it came off of high idle it leaned out to 14.2:1 at Idle. When reved up quickly at Idle, A/F went anywhere between 12.9:1 to 13.5:1 depending how quickly and how much throttle was twisted. Upon constant throttle at around 3-4000 RPM A/F was around 14.5:1-15.2:1. These figures are NOT rich, nor are they lean. I also unplugged the intake air temp sensor to see if it would richen or lean it, and It did NOT. No change at all. I did this while engine was running to make sure it was a fair test. I also removed the air box lid and the A/F ratio did not change either. I also did this while engine was running. My conclusion is the factory Fuel map is not to bad and not effected too much from exhaust or intake mods. The map has a decent lean cruise at 14.5-15.2:1, and a decent idle mixture that is just SLIGHTLY rich at 14.2:1. Cold start is spot on at 13.5:1, but fuel enrichment at Wide open throttle is a bit lean at around 13.0:1. I would like to see 12.2-12.5:1 at WOT(Wide open Throttle) and maybe 14.2:1 at a steady cruise. So I would say that they do not run rich from the factory, but just a Tiny, Tiny bit on the leaner side, but nothing to worry about. I think the bike could benefit from some more fuel, but just a little.