For a while there back around 1999 I had a mostly interstate commute, actually basically the same commute I have now, but instead of doing it in 45 minutes like I am now I was doing it in 30, and I would get over 110 quite regularly and topped out at 115, so I've never seen the 120 my bike was theoretically once capable of. Weaving in and out of traffic, and passing cars like they were standing still in 65mph zone. I had just put on the fairing, and that made holding on over 100 MUCH easier, and when you do the same drive day after day on wide open interstate those 100+ speeds started feeling not so fast.
Now I knew even at the time I was being stupid. If I got pulled over I would have been arrested and fined something I couldn't possibly afford to pay. If I got surprised by a deer, or cut off unexpectedly by a car, or any number of other little things went wrong, getting arrested would seem like a party by comparison, but the bike handled it easily, and I kept doing it anyway.
Nowadays I'm a lot more intimately aware of my own mortality, and maybe I feel like I've got more to live for, so I keep it under 90 most of the time, but on a good straight I might still crack open the throttle and push it up past the Ton just because I can.
A couple of things to be careful of though: 4 am is a GREAT time to meet deer, so probably not the best time to try to crack 100. You don't need to rev it in 4th to get over 100 on a CB750. As long as you've got lots of space. Rolling on in 5th at 80mph works fine and draws less attention.
Most of the roads are curvy here in Vermont, so except on rare long straights it's tough to find the space to do it here in VT except on the Interstate. We're fortunate, Interstate traffic is not too dense. I'm not sure what the roads are like where you are, but I'd pick one that's both adequately flat and straight so you've got plenty of line of sight, and not overly patrolled by the popo. Good luck, and be safe!
