scary moment

[obfg]

I went for a little ride to-day. Weather clear, hot and windy. The road is familiar to me, but I had not been on it for a month or so. This is not a loop ride, rather up and back on the same highway ( two lane ashphalt.). At any rate, there were five or so areas under construction ( culverts being put in and those areas covered with gravel prior to paving). However on my outboard run they did not cause any concern, just slow down (it is an 80km zone [50mph to our southern neighbours]) to about 30km and be relaxed. On my return I had thought I had gone past the last of these areas and was going a tad faster, maybe 90km. At any rate, came around a curve and saw four orange barrels outlining a 50ft ( I am an old fellow and have not made a complete transition from imperial to metric measurements) section of the road about 50yds in front of me. This construction was out of the curve on a straight section.
While my mind was thinking "oh @#$%!!!" my hands and feet were grabbing brakes and clutch. I think I hit the rear brake first but only just barely.

At any rate the bar started to dance the twist!!! I immediately came of the brakes and the shimmy stopped. Hit the rear brake and came down to a managable speed just before entering the gravel. I was still on the clutch and for some reason the bike had stalled. When I was back on the pavement I relased the clutch and the bike started right up.

I have practiced hard braking and have never had the bike wobble before. So my question is, does anyone have an explantion for this wobble. If it matters my bike is a 2000 kawasaki concours.

Thanks in advance.

[ceemes]

Nice bike, mines a 1987 Concours, Johnj also has one. What you experienced or rather almost experienced is call a tank slapper, where the front wheel and handbars start to oscullate due to a lack of traction and over correction....at best you recover from it like you did and just need to change your undies when you get home or at worse, lose total control and crash. I have had about five of them in my riding career, three as a courier and riding too hard into a corner. Four of them ended up with me sliding on my butt down the road and I was able to recover from the one on the Sabre. So far, I have yet to experience any inherent instability or tank slappish behaviour from the Connie, although she does like to kick out her tail a bit if I apply a little too much throttle off the line or going around a tight corner when it is wet out.

[Johnj]

The only wobble that I'm aware of is when decelerating through 50mph (50 - 45) it will start to tank slap, but I've never heard of it being so bad. All you have to do is tighten up the steering bearing and it goes away.

[Wrider]

If the bike stalled, I think you locked up the rear temporarily which would cause your tankslapper.

[obfg]

Thanks everyone for the input. I guess alls well that ends well.

[Stir]

Welcome to the wobblers club. My Vmax is quite familiar with it.

If I may... perhaps it might do you good to check the load settings and lube of your forks after the suggested tightening of the steering bearing. Unequal amounts of fork lube and uneven load settings can likewise cause wobbling in deceleration or shift in weight to the front. Sit on your bike and push your forks down by applying the front brakes to get an idea of your fork's condition. Then check for oil collars on the shock's shaft. You might need to replace the oil seals. Perhaps you might also want to check your front calipers and your rotor disc. One short or dragging leg makes a limp and makes the shoulders wobble in slow motion but not when walking leaned back. Same thing... the best gymnastic dismount lands square on both feet.

By the way, when you tighten your neck, place your bike on center stand and lever up your bottom so that the front wheel is raised off the ground. The correct tension of the steering bearing will not make your handlebar bounce after it's slightly nudged to drop on one side.

Just a safety reminder... the front wobble always behaves when a little throttle is applied.