I am an ex Super biker, a shimmy or tank slaps are relatively common on some bikes specially when you lay the power down and you loose partial front wheel contact force. On problematic bikes we would simply installed a damper and the problem was gone. If I were to guess a damper would cost around 250$ for an entry level unit from any good bike shop. Tank slaps are so feared that many bikes are fitted with dampers just in case. And hell they are scary. -- Jannie du preez --
