Wobbling, weaving or wheel bouncing at high speed is quite possibly your bike’s way of saying it needs some mechanical TLC. Nevertheless it can be quite scary when it happens unexpectedly. Whatever you do, don’t grab a huge handful of front brake. That way only leads to a locked wheel or a highside.
Instability due to front wheel and handlebars oscillating from side to side (as though they want to ‘slap’ the sides of the fuel tank), making steering difficult or even impossible. Often set off by front tyre hitting a bump under acceleration.
Check the adjustment of any steering damper fitted, front tyre pressures and check for looseness in the steering-head bearings.
For gentle wobble: Slow gently and increase the load on the front wheel. When the handlebars oscillate, resist, close the throttle gently, move forward on the seat and lean forward to increase front wheel loading. Sitting on the tank works well on some bikes.
For violent wobble: Don’t try to resist the oscillation by stiffening your arms. Accelerate to decrease the load on the front wheel. Lift off the seat, pull back on the handlebars and open the throttle as though attempting a wheelie.
Rear of bike oscillates from side to side. Less dangerous than a tank slapper though still disconcerting.
Loose wheel or rear-suspension bearings. Worn or ineffective rear suspension damper. Poorly designed, rear-mounted luggage systems. That said, some bikes simply have a disposition to high-speed weave given particular speeds or conditions.
High-speed weaves can occur during straight running or when cornering under particular conditions. In both cases close the throttle gently and softly apply the rear brake.
Occurs when either wheel (usually the front) bounces up and down rapidly, causing severe vibration.
Badly out-of-balance wheels are invariably the cause, although even well balanced ones can be prone to wheel-bounce where in-tyre puncture-sealing liquid has been used.
Slow down by easing back the throttle and applying the rear brake gently.