Violent Steering Wobble on Deceleration?

[Ruggybuggy]

So I go for a rural ride with my new FZ1 bars installed and my the2wheel.com levers fitted which were very good modes. I'm on a curvy rode and riding at speeds between 80-100 kph (50-60mph). I came up on a slower moving car and decide to pass on a short straight stretch. I dropped two gears and the bike accelerated quickly and as soon as I get off the throttle and the bike pitches forward I get a violent steering wobble that only lasted for half a second. I made the shift and finished the pass. So what caused this? My thought was that when I accelerated hard from around 70kph the front wheel lifted slightly off the ground. I was probably pulling back on the bars from the acceleration caused by the slippery Yamaha comfort seat and my textile pants. When the tire was planted firmly on the ground I probably had the bars slightly out of position and this started the wobble. Sound plausible?

 

[PhotoAl]

Scarry! I'd be checking everything about the front end. Have read of FZ6's having head shake but it seems to be quite rare - Ive never experience it.

1st would be tire and tire pressure. 2nd would be to make sure the front is not dropped or lowered. The top of the forks just be even with or slightly higher than the top of the top triple clamp. 3rd would be the steering head bearings to make sure they are not loose or worn. Check to make sure noting in the front forks is tweaked, front wheel bearing are OK and both forks are damping similarly. Please keep us informed as to what you find

 

[Ruggybuggy]

Forks are in the stock position, tire pressures good and front wheel bearings and head bearing have no play. The bike has low mileage and is in perfect mechanical shape. The tires have only around 3,000 miles on them.

My feeling is that this can happen on any FZ6 if the conditions are right so my experience was either rider error or and external force like an irregularity in the pavement.

Watch this extreme case
[ame="http://www.youtube.com/watch?v=RbgYRJMMS9M&feature=related"]http://www.youtube.com/watch?v=RbgYRJMMS9M&feature=related[/ame]
Mine wasn't anwhere near this bad.

Was somewhat worse than this.
[ame="http://www.youtube.com/watch?v=S7UxmOt7U1Y&feature=related"]http://www.youtube.com/watch?v=S7UxmOt7U1Y&feature=related[/ame]

 

[Motogiro]

Some minor wobble is very common when the front wheel lifts and sets down again.. I've had it happen with the FZ6 where there was also no wobble.

Check all the common areas like steering bearings, tire air pressure.etc.

 

[jazzpaintball]

Anyone else watch the videos and say "Why on Earth did they post that...? It makes sport bike riders look horrid..."

The bottom video "tank slaps" were very mild by the looks of it. I have not used the FZ1 bar, but I know clip-ons have higher tendency for tank slap. This is due to less pressure that you can get onto the bars (less bar = less pressure - ape hangers dont account into this....).

If you are worried about it though, might be a good time to look into a Ohlns (hope i spelled that right), or a similar brand, system.

 

[Ruggybuggy]

If you are worried about it though, might be a good time to look into a Ohlns (hope i spelled that right), or a similar brand, system.

Not worry enough for me to run out and spend $600 bucks. Just wondering why this happens and if it was something I did what can I do to prevent it?

 

[jazzpaintball]

Not worry enough for me to run out and spend $600 bucks. Just wondering why this happens and if it was something I did what can I do to prevent it?

My appologies, I did not know they were anywhere near that price.

As far as prevention goes: just be smooth. Most times I have seen tank slap and gotten tank slap was when the bike underwent a heavy change. Heavy change in speed, pressure, weight, etc. Mostly when the wheel comes back down from a wheelie or a heavy acceleration that took a lot of pressure off the front end.

Maybe they have changed a lot in the last couple years, but 2 years ago I was looking into a steering dampener, and I was able to find them constantly between $100 and $150.

 

[Ruggybuggy]

Maybe they have changed a lot in the last couple years, but 2 years ago I was looking into a steering dampener, and I was able to find them constantly between $100 and $150.

If I could find one in the 100-150 range I'd would have it. I had one on my Suzuki Vstrom and wouldn't hesitate to put it on the FZ6. The cheapest I could find was about $400 and that was a no-name type stabilizer which I wouldn't trust.

I'm not to worried about the mini tank slapper. I wonder if anyone has had a full on slapper like the one in the first video on a mechanically sound FZ6?

 

[tejkowskit]

Don't grip the bars super tight, too. Keep a loose grip. If you are too stiff, the wobble will only be amplified into your body. The bike will straighten itself out.

 

[Ruggybuggy]

Don't grip the bars super tight, too. Keep a loose grip. If you are too stiff, the wobble will only be amplified into your body. The bike will straighten itself out.

Well I was sliding back on slippery comfort seat and my textile pants that cause me to pull back on the bars. I ordered a TP seat which should solve the slippery problem.