Do you mean "Vibration" or do you mean handlebars "shaking" back and forth(wobble), vibration could be a multitude of things, shaking back and forth, as mentioned above, is usually a bad tire or neck bearings need adjusting or replaced
The definitive test for steering bearing problems is to get up to about 45 mph on a straight level road. Take your hands off the grips but keep them where you can rapidly regrip when needed. As the bike slows, does the steering start to wobble back and forth getting worse with time and as you slow? If so, this is usually a sign of bad or loose steering bearings. On a 1300 it could be either the bad stock bearings or a loose castle nut holding the steering stem in place and putting the correct force on the bearings. On an 1800 which comes with the better performing taper/needle bearings, these usually do not go bad but, rather, the castle nut can become loose.
Ha, ya i have been around scooters all my life.
I still think of my self as a Harley guy but i Love the VTX equally.
Rat traps, jockey shifters and ape hangers may put a few to scratching their head wondering WTH is he talking about?😳😆
Thanks for all the responses, guys. I do have risers and no the handlebars are not wobbly. I mean I can move the handlebars back and forth but not sideways. I'll be checking the bushings but can't find the time to do any kind of work on the bike.