As an owner of a xc500 I can only say welcome to the best scooter group, the xc500 is tops.
Regarding cold starts, the gel battery is a Must! Also regulator, solenoid, decompression cam, and alternator must be checked out to eliminate them from being the problem.
I have had all the mentioned items replaced, plus the starter, and best long term result was replacing alternator,and regulator, after doing the battery first. It has been trouble free starting for the last year now.
Sent from my Mi Max using Tapatalk