This one I know!! There is a shaking handlebar at all speeds above 45-50 if you let go of the handlebar? If yes, the issue is with a loose nut of the rear wheel where it is connected to the swing arm. It should be torqued correctly but regular SVCs don't have torque wrenches. Anyways, it can be done in 2-3 trials even if the mech is not aware of the issue.

One of my co-riders on a tour had the exact same issue on his RTR. I had gone with him to the mech's but was somewhat distracted when he did his thing. On asking, this is what I was told. The guy was riding the severely wobbling bike for over 600km till then, and all it took the mech to rectify it was 3-4 minutes. The issue never re-occured at least for the next 2.5k km till the tour ended.