several seperate issues here on your ulysses and i'd break them down to the battery....too much oil in the swingarm...moisture causing starting/sputtering issues. check the following:
1-wet/corroded battery cable ends and terminals. remove seat and check. do NOT rely on what you just see. remove both cables, clean, reinstall and tighten. often times for various reasons the battery terminal connections if not pristine will give you a CEL.
2-remove fusebox cover. look at schematic. it is either on side or inside bottom. find your ignition and key switch relays. remove and check the blade tips. switch them around and reinstall. check the fusebox for moisture. i would also remove the battery blade fuse and do the same. it can trigger back-firing and CEL if the blade tips are corroded/wet.
3-if equipped check both your sidestand and clutch lever interlock button switches for solid connections and corrosions. a problem with either one can cause a no-start problem.
4-give the battery a healthy charge and check its age. a chinese POS brand 1 year older or more is suspect. a quality name brand battery 3 or more years old should be load tested. a healthy charge is 6 amps for 20 minutes minimum and NOT with a stupid tender.
5-you added too much oil. the excess sumped, was pushed thru the motors' breather system and into your airbox. you need to start from square one on this. leave the filter installed. completely drain the 5/8th plug on swingarm and let drain for minimum 30 minutes. junk it regardless of what PO told you. oil cheap. with filter installed and UNTOUCHED....add precisely 2-1/4 quarts of a quality 20-50 oil. could care less what you use but add precisely that amount. the swingarm will now be properly filled to spec.
6-IMPORTANT: XB's cantankerous to properly check oil levels on. THIS is the single correct method. run the bike minimum of 10 miles. park on level surface with nothing under side stand. shut off. get off the bike, get a clean rag, wait 30 more seconds....NOW check the oil via the dipstick. THIS is the correct method. if your air filter is a stock paper style and is saturated with motor oil it must be replaced.