Are near-tank slappers normal??

[03boltintheplains]

Hi, I'm new here and have a 03 white xb9r with just a jardine slip on that I've been riding for a few weeks, first bike and I'm lovin it so far. But last night I was on the highway cruisin at 65ish and it seemed like all it took to send my handlebars wiggling erratically (only about an inch of motion or maybe less) was a decent gust of wind. It really took me by surprise because I was just in a straight line at the moment and wasn't on the gas hard or anything. The previous owner lowered the suspension but I'm not sure what else he adjusted on it other than the height but I think that might be the cause of my issue. Any help is appreciated.

 

[Stevenc150]

Set your suspension up via the Owner's manuals recommendations for your weight. They won't be perfect, but they'll be close. (You can look at them for free on Buell.com through the "Owners" section if you don't have one).

Probably need to check your steering head bearings as well, they're probably due to be changed. Check wheel bearings as well. 6 yr. old bike will probably be needing a few items to get it back to peak condition.

Either way, congrats on the bike and welcome to the Forum! [up] Lot's of help to be found on here so post up what you find out. Good luck and ride safe.

 

[racepro716]

I've commented on this before, This is NOT a tank slapper!! Your bike is just kinda shaking it's head a bit. Without a death grip on the bars it'll sort itself out and you'll continue down the road. As I understand it a true "tankslapper" means the bars are going lock to lock about 10 times a second. I understand this is your first bike and it seemed scary but follow Steven's advice and all should be well. Oh ya, with steering geometry like the Buell has I'm guessing raising the forks in the triple clamps is asking for trouble. Good luck! wayne

 

[03boltintheplains]

Yeah after a bit more reading I realize it's called a speed wobble, if you're not praying yet. I have to go to work now but will reset the suspension to my weights recommendations when I get home and take it for a ride.

edit: I realize that it is a 6 year old bike but with only 6,000 miles I can't imagine bearings are already shot.

 

[Lordfenwick]

Don't be so sure.

XB wheel bearings can last little more than 5K miles and have been known to fail after much less. Steering head bearings are much the same. If the bike has been wheelied a lot in its past life, both front and S/H bearings will certainly be shot. Even pressure washing the bike can have an effect on bearing life.

I changed my tyres at 4K and the noise on the balancing machine of shot bearings was significant. I couldn't feel any play with the wheel in the bike, but with it out the rumble was awful. i changed the bearings and the wheel ran silent.

Other things that have affected the front on my bike are:

1/ Tyres. Some are less stable than others. With Michelin Pilot Powers steering was extremely sensitive to road condition. With Dunlop GP racers it is rock solid.

2/ Wheel balance. Some tyre fitters are incredibly bad at their job. Balance weights need to be on the brake rotor side of the front wheel and you would be surprised at how many fitters get the weights wrong.

3/ Tyre pressures. Try 38 psi front, 42 rear. Too low and the front feels vague and doesn't inspire confidence.

4/ Geometry. I have raised the rear of my bike by 5mm. This quickens the steering but makes it far more likely to shake its head on bad surfaces. It's a compromise that I am prepared to live with.

5/ Suspension set-up. Incorrect settings can make a huge difference. If the previous owner was 17 Stone and you are 10 stone then it aint gonna work. Read the book, but set it up for a bit heavier if you ride quick.

Finally. if you nail it on bad road surfaces or when cranked over for a bend, it's gonna shake it's head a bit. Relax, let the bars go loose, power through it. Don't hang on for grim death. If you do that, then it may turn into a real tank slapper like this one:

 

[SoreandSorry]

Steering damper is the only way ill ever get on a bike again after my accident put me in hospital minus most of my skin. CHEAP insurance, skin however or your life isnt. And when in doubt, I usually change all bearings, filters and consumables when buying a new vehicle

Just my thought. enjoy the bike!

 

[Stevenc150]

03Boltintheplains, here's a thread on wheel bearings. If you've still got the ones with black seals on them, they need replaced with the upgraded orange seal ones. - '03 with 6700 miles - Wheel bearing Ques.

 

[03boltintheplains]

Just went out and checked and both wheel bearings have the orange seals, and the last guy that owned it seemed really sensible for a sport bike rider around here and I don't think he wheelie'd much, although I might have gained some ground clearance pulling too quick of a shift that was only once and less than a foot. I adjusted the preload to my weight and the damping to the second softest condition in the service manual cause there really are no twisties around here. The improvement was huge though, WAAYYY more confidence inspiring. Right after I bought the bike and got over the difference in position and steering, being used to riding my brother's sportster, I kind of thought to myself "damn, this is the best in the business?" Now it's more like "DAMN! This is the best in the business!!" and that's the second mushiest set up. I think the last set up must have been half guessing for it to have been that bad in comparison. That said I didn't get a chance to go out on the highway before it started pouring rain, and I just detailed the whole bike about 3 days ago so I figured it can wait for the highway test. I'll also try adjusting the tyre pressures, I didn't want to touch them because I wasn't sure how increasing/decreasing tyre pressure on a bike affected handling.

 

[driftingswiftly]

Lordfen, why do you say the balances should be on the rotor side? The wheel can be unbalanced in the axial, radial and rotational directions, so why do the weights have to be on the same side?

 

[veeemdoubleu]

as my first buell my bolt did the same at 90 MPH hitting a bump just relax your grip and lean forward a bit and ride it out. its normal.

 

[Lordfenwick]

Hi Driftingswiftly,

Simply quoting the service manual...........

"1WARNING
Do not install balancing weights under the stand offs for
the front brake rotor. Contact could push rotor out of
round. Braking could result in brake failure resulting in
death or serious injury.
3. On the front wheel, locate a flat surface on the right side
of the wheel rim. On the rear wheel locate a flat surface.
Press weight firmly in place, holding for ten seconds.
4. Allow eight hours for adhesive to cure completely before
using wheel.
NOTE
If wheel assembly is out of specification (1 oz. front, 2 oz.
rear) rotate tire on rim and rebalance until wheel is within
specification."

I know what you mean and would also be interested why Buell say RHS only. I decided to go with the experts on this one though!

 

[driftingswiftly]

hmmm interesting. Good call tho. Its safe to say the book knows best...well better than me at least. Thanks for the info!