My buddy had the exact same issues with his harley, bike would try and stall/die, running poor/rich. Lights were acting up. Turns out the battery had shit the bed even though it would start. Try a new battery or swapping one from your buddy's to try it.
2014 XC - Pearl White - 16" Ape Hangers, LED Headlight, Lloydz Timing Gear @ +4, SharkHonker Exhaust, PCV, 1/4" Turn Throttle Ring, Hard Lowers, Keyless Ignition, Lloyd's Intake, Klockwerk Shield