There are basically two types of motorcycle steering oscillation: high speed and low speed. The low speed type is usually seen around 40- 50 MPH, and is seen as a slow, steady wobble of the handlebars that diminishes with either a speed increase or decrease. Very common on motorcycles and often taken care of with nothing more than damping of the steering or just learning to ignore it. It is not dangerous, will not increase with speed or any input to the vehicle (acceleration, deceleration, turning).
A high- speed oscillation is something entirely different; it is an oscillation that is 'fed' by the dynamics of the motorcycle's movement and will almost always increase with speed. It can and often increases with a shift in load on the bike; this is the classic failure mode: the bike starts to oscillate at high speeds (let's call it 60 MPH and higher) and the rider reacts with a sudden and complete reduction in power (closes the throttle). This in turn puts a weight bias on the front wheel, or moves the center of force on the wheels forward, and often INCREASES the speed and amplitude of these oscillations, sometimes resulting in an uncontrolled 'steering stop to stop' front wheel movement (i.e., a tank slapper) that never has a good outcome.
Motorcycles are carefully designed to avoid high speed oscillations, starting with the geometry of the steering, and ending with aerodynamic testing. Most motorcycles are built in such a way as to make them self- damping and thereby avoiding the dreaded 'tank- slapper'. There are exceptions: a lot of liter sport bikes come with steering dampers for that very specific reason- to damp the high speed oscillations incurred by the aggressive steering geometry and the short wheelbase. Neither of which apply to the C-14 by the way.
Just my own personal opinion but a sport touring motorcycle should be stable to any speed the rider cares to or can reach. If anyone ever suffers a steering oscillation on something like a sport tourer, I would strongly suggest that person find and correct the root cause of such oscillation before riding it at anything above secondary road speeds: maybe 45 MPH or so. It is probably nothing but tire wear and / or balance but again, it should never happen and it should never be tolerated, accepted or ignored.
So to directly answer your question: yes, high- speed wobble can turn into a tank- slapper and I believe that should be avoided.
Brian
Oh so many variables,
i already had the front tire off as i did a rotor replace and checked the front bearings. the steering stem seams fine. Both front and back tire have the cup on the right side. i was not too worried about it but now since i have a trip coming up that will take about a 6 hour ride and burn through some mountain roads, i am wondering if it would be best to just get new tires so i won't have not cornering issues or un-predictability.
what is the worst that wobble can turn into, tank slapper? I have been riding since the 90s so i am no expert but also never experience this before.
