Riser Bar

Why does my V Star 650 wobble when I ride? Seems like something is loose.?
I have a 1999 V Star 650 Classic with 28k miles on it. When I ride, I get the sensation something is loose in the frame or suspension. It’s like the front wheel and forks are hinged seperately from rear of bike and not tight. When I slightly wiggle the handle bars back and forth it seems like it gets “speed wobbles” and maintains the wobble action on its own. Rear tire seems “slippery” but I can’t find any play anywhere when bike is parked. Rear tire is also wearing too quickly. I have handle bar risers but that should not be the problem. Bike did not do this when I bought it at 18k. Anyone heard of this problem????
front tire might be out of balance.