I finally got around to changing the oil in my 94 Sportster 883. Well, during the process I notice that I have 1/2" screw sticking in the front tire. Anyways, I 'unscrew' it a bit and it leaks air; so I've screwed it back in, but haven't rode it since noticing. It's my first bike and I really know nothing about the tires. Do I need to replace the tire? Is it tubeless or can I just replace the inner tube? I don't want to take it to the dealer and get talked into something I don't need.