Tank slappers can be tricky – you so much as touch the front the front brake and you’re gone – touch the rear brake and it pushes the front of the bike down while it’s unstable (and you’re gone just the same)
Last time I was in that situation was years ago – close to 100mph on a Suzuki GT550 triple – my friend following behind said my rear wheel was going from side to side at about three feet. (Rubber swinging arm - what can you do)
I had no choice but to ride it out, “feel it through”- possibly more luck than judgement, but I figure the message here is “no sudden moves” …..
More gear is always an good idea and I try to follow that rule when I ride my Harley. However, you’d need to be dressed up like Ironman to come out alive after passing under the wheels of a semi. The leather would “maybe” hold some of the parts together. I used to paraglide and had the backpack motor that went with it. I sold it because of a few close calls that scared the hell out me and bought the Harley. Looking back at that decision now I think the paraglider was safer.Some bikes are more stable than others. He should consider a different motorcycle, AND he should start wearing more gear, judging from the tore up pants and injured leg. Most people don't think of these things until after something like this happens.
Never experienced a tank slapper. Is it something that only happens at high speeds? I've only ridden dirt bikes and cruisers.