contrary to some BS you've possibly heard and might also hear on here...the 2003 XB was a fine bike with minimal teething problems. only came in the 984cc version that year. i owned 2 of this exact firebolt thru the years and never had a problem with either one of them. IMO it has a slight lifter tap from what i can hear. these are sportster based 4-cam/4-lifter motors and some that have visited redline and beyond too many times tend to generate this "tap" or "tick".....reveals itself as the motor warms up. often times a quality 20wt-50 cycle specific conventional oil such as castrol actevo-----maxima----belray-----PJ1 calms it down. also check for rocker box cover oil leaks....oily residue around the rear fan housing area.....and oily residue atop the rear of the engine case at the box vent. all tell-tale signs that it's been subjected to excessive heat and alot of trips to redline. and for what it's worth these motors inherently noisier than the H-D big-twins you might be used to...plus the fact that the part of the engine being the heads and upper valve train that inherently generate the bulk of the engine noise are housed within the parameters of the frame assembly causing a bit of acoustic resonance and "noise" not heard in other H-D based air-cooled twins.