Hi guys, I am a new rider and have a 2012 xvs650 custom. I am looking to change the rear signal lights to after market lights. I attempted to remove the lights from the rear fender stay and unbolted the small bolts on the chrome section of the light but that is as far as I got. How do I remove the black rubber base? Also how do I know what thread size of lights to buy? Thanks a lot for your help!