A bike's tendency to produce a tank slapper is directly related to the steepness of the steering head angle and is inversely related to the steering trail. Sport bikes, which have more vertical steering angles, are more likely to produce this effect (that, and the fact that sport riders like to do wheelies, which sometimes induce steering wobble on landing), which is why they usually have integrated steering dampers. Bonnies are less likely to have this problem because they have larger steering angles and longer trail. Nonetheless, I installed a steering damper on my Bonnie. I think of it as life insurance.