Originally Posted by
SquidPuppet
Glad you saved it.
I very much doubt you caused it though. In the motorcycle world, "Tank Slappers", are caused by unstable geometry. Certain extremely aggressive Rake/trail/short wheelbase combinations make for an excellent handling racing motorcycle for cornering and quick change of direction. But they result in nasty straight line instability, which is exaggerated at higher speeds and by bumpy surfaces. It's actually the accepted norm and that's why you'll see serious dampers fitted to all race bikes.
As you know, it doesn't really matter what initiates the wobble. Once started, they take on a life and energy all their own. Even if everything else, bearing adjustments, spoke tension and true, frame alignment, etc, are perfect, some bikes are just very likely to do this once they reach a certain speed. Of course I don't know if that's the case with your bike. It may have been a one-off incident caused by a group of factors all occurring at just the right time. I hope it was just a freak occurrence.
The "Great" thing about a really violent slapper on a motorcycle is that head shake will drive the brake pads and pistons ALL the way back into the calipers. So if you survive the wobble, right when you need the brakes, you have NONE. And it usually takes quite a few pumps to restore the hydraulics to normal operation.
Not in all cases. From personal experience, had an agressive 'tank slapper' on a brand new GSXR-1100 in 1986. First year import to the US. Factory equipped with a damper. To properly break these tight motors in, one would rev to redline in most gears and under load. Mine might have been one of the first releases as Suzuki never advised of the potential disaster awaiting.
The violent wobble only came from straight line and rolling off throttle at well over triple digit speeds. When first experiencing it, scared the jeebeez out of me and the effect was so wicked it transmitted thru the chassis to the rear wheel. Thats how bad it was. To save it, had to roll back 'on' the throttle, then drag some rear brake and slowly roll off the throttle, all while praying I have enough time and distance ahead of me.
My bike sat in the service department only a few days when a recall notice came in. The problem - improper headset preload. After that and even some time later with highly modded motor and gearing, the bike was bulletproof.