I would have thought that if there was a major safety issue such as the tendency of a loss of control due to a design fault then law suits would be flying about (especially in the U.S.) and Suzuki would have done something about it, like the did on the TL1000S some years previously, when in all probability there wasn't anything wrong with it at all. I would suspect that a tank slapper like the one you describe would have had another cause. As an example I used to have a Ducati Pantah and fitted some new Pirellis and on the first ride going over a small hump in the road in a straight line it went into full lock to lock tank slapper. I stayed on the bike but it broke the steering lock stops, kinked the front wheel, slightly bent one of the fork tubes and dented the fuel tank. It also damaged my right wrist which took several months to get back to normal. Pirelli wouldn't admit any liability but took the tyres back and sent me some different ones. So that was very definitely down to the tyres as the bike had always been super stable like all good Ducatis. My ZX6R would shake it's head quite alarmingly when going hard on bumpy roads, but this was completely cured by getting the suspension (pre-load, compression and rebound damping) all set up properly. Other things that can cause front end problems are weight distribution I.e. too much on the rear making the back squat down too far, made worse by too stiff front forks making the front too high. We all know of the buffeting problems with Vees and Wees but although this is an aerodynamic problem it is more related to discomfort and irritation rather than a safety issue. I can't find anything in the owner's handbook saying not to exceed a specific speed. All it says is not exceed 9,500 RPM, which I guess would be around 150mph. Maybe down hill with a tail wind...
