I've had one, decreasing radius during a track day got me, I overpowered the front tire, it skipped and went wrong from there.
Throttle and a steering damper (God had a hand in it too, probably 99%+) saved it. That was on a Hayabusa, not even had the front end quiver on the 1125R.
Had a good one on a GT380 with a large cooler full of beer on the luggage rack way out back. Was on a section of 5 lane that curved sharply, and was well used to the turn, so input was normal & reasoned. The C.G. change ( and non damping forks, dented steering head bearings & Satan laughing ) started a wobble & the bike walked across 4 lanes before it went away. Quite spectacular from my point of view. I take no credit for anything but hanging on, I certainly couldn't muscle it away.
I've had "shake" on my XB9R when coasting with my hands off the bars. New tires cured it. On my 72 h-d Sprint,I had "oncoming" in my lane on a curve. I went to the shoulder and coming back onto the pavement,got into a full fledged tank slapper that was laying rubber with the front tire. Let go of the bars and it corrected itself. All tho the shoulder was graded pretty close,that twitch between the shoulder and the pavement set it off. X1 tried to do it when I landed a wheelie a bit crossed up. You simply have to land with the bars straight to the bike and correct your course "after" you land. On the other hand,back in the day with my 71 Baja dirt bike,I could go down a gravel road at 50 or so and purposely slap the tank as fast as I could and the bike kept going straight......making a mess of the gravel and spewing said gravel on my ride friends. What fun........
Road Atlanta 2009 WERA GNF. I came off the rumble of Turn 5 somehwere near 100mph. The front, then the rear hit a hole. Violent tank slapper ensued. I was able to get the weight off the the front end and let off the the throttle. I slowed and the tank slapper became less violent.
I think I then touched the throttle and the tank slapper went super violent, tossing me from the bike...
Among other things I've owned an '81 XS1100RH (the "1.1") and an early GSXR750, and ridden quite a few bikes like KZ1000's and GT750 kettle's, so I've seen a few slappers, but never had an accident because of one.
When I'm buying a bike I like to take my hands off the bars at 80km/h to see what it does. If the suspension is worn or setup badly a bike will often oscillate at that speed.
Freakiest one was a KZ1000ST, belonged to the shop I worked at. Cruising home one night after work, almost home, going up a gentle left hander with a slight crest in it, on a steady throttle... WHACK-WHACK!!! The bars went full lock left, then full lock right... then back to normal as if nothing had happened! Freaked me out just a little. Worn tires, old suspension, and not the stiffest frame in the world were probably the cause.
The X1 can be twitchy over bumps, but nothing approaching a tank slapper. The 1125R seems to laugh at the mention of the idea
It happened to me on my 1991 Kawasaki ninja 600. I was riding through the canyon on a right hand slow sweeper and the front tire hit a big pothole.........It went into a violent tank slap and went from lock to lock more than 15 times before i could accelerate out of it. I only knew to accelerate to get it stop because i had seen it on a show on tv. At the exact moment i was in mid tank slapping. I was passed head on by a huge mac dump truck, I kept seeing it coming and thinking im going to splat on the grill like little bug!! Man that was the most scared i have even been!
I experienced one, it was on a 1970s Yamaha CS200 (purple and white 2 stroke) . I was trying to do a wheelie, sort of succeeded and must have landed with the wheel turned.
One of the more scary moments I've ridden through. I let go of the bars and sat back, after a couple seconds it stopped and me, with some new paint on the underwear, continued on my merry way
I have had a few tank slappers after some unexpected moments with the NineR when it went completely airborne and came down with the front wheel not perfectly straight.
I go limp but still hang on. I try to let my feet fall off the pegs and let your limp-ish body absorb the oscillations. It has worked for me a handful of times. I have not yet went down because of a slapper nor have I felt the need for a dampener on any buell I have owned tube-xb-1125.
I found a demo on youtube, this is the closest demo to my strategy.