Why do motorcycles wobble at high speeds

Sven_GSXR750W (deleted)

29.08.2005 22:10

Hi guys.

I have the following problem. At 160-170 rum the bike often starts to flutter. The
whole machine begins to rock. The bike calms down only when you take off the gas.
Tires are new. Clothes can't be there either because leather suits.
First I set the chassis to standard. Didn't help.
What could that be??

As an absolute newbie, I can't think of too much.

Who knows the problem ???


M.f.G Sven

Dutch Offline

Heinz G. Konsalik


29.08.2005 22:14
# 2 RE: Flutter at high speedreply

Did you have removed the fork tubes?
and reinstalled under tension? If so:
Just loosen the axle clamp and sometimes
Feather properly while standing.
Then the axle clamping again with feeling
tighten and test drive ...

Gehesicksärr ... I'm missing one!

Sven_GSXR750W (deleted)

29.08.2005 22:32
# 3 RE: Flutter at high speedreply

Nothing the same. I'll have the fork done. I don't have 2 left hands
but I have to gain even more experience in screwing my bike.

hoschi Offline

Cheffe de Grill



29.08.2005 23:05
# 4 RE: Flutter at high speedreply

I tip on steering damper.defeckt
Remember "The tire is also paid for outside"

gobedi Offline

Keyboard tormentors



29.08.2005 23:45
# 5 RE: Flutter at high speedreply

Which new tires did you fit?

The question is because I am currently experiencing a similar circus since I installed the new Metzeler Z6.
My fat man performs a real egg dance.
________________________

Greetings from the Rhineland

Et kütt like et kütt, et nothing necessary!

DER Christian (deleted)

29.08.2005 23:56
# 6 RE: Flutter at high speedreply


Egg dance with a Z 6 ?????

It is normal, VERY stable in the straight line ..


To the question:

- Check the air pressure, check the setting of the fork / shock absorber (better again!), Check the steering head bearings, check the steering damper, and, quite banal: check whether everything is secure! Axles, swing axle, U.S.W.


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Sven_GSXR750W (deleted)

30.08.2005 00:27
# 7 RE: Flutter at high speedreply

Hmm ... That makes me questionable now. I also installed the Z6. And the whole thing was balanced by the expert ...

How much pressure do you have on it ???

Or .. Which pressure is advisable for the front and back ???

gobedi Offline

Keyboard tormentors



30.08.2005 00:32
# 8 RE: Flutter at high speedreply

Hello, still there?

There are a few small things to complain about here and there, but I still blame it on the tires. I usually ride durable touring gear (ME Z2, Macadam 90). The last combination was Z1 / Z2.

- Air pressure could be a little too much, I'll check again
- Fork recently redesigned by Wilbers
- Strut is pretty much in the bag
- Steering head bearing is great, screws should be tight
- I haven't needed a steering damper for 7 years

The hottest is:
I sold a set of Z6s to a friend (drives GR7AB as standard) six months ago. On the question of whether he is satisfied: "Grip knot, but somehow goes straight ahead at full steam"

Of course, I ignored the hint.
On Sunday when the weather was great, I had the opportunity to test extensively:

- Grip and handiness are unusually good, almost too manageable
- no problems in curves, tight ones were problematic beforehand, especially with bad surfaces
- Straight-ahead running smoothly when driving comfortably
- Straight-line stability with real pressure on the rear wheel is very restless, especially acceleration in the third and fourth, comes emotionally from the front

In retrospect, what I don't like about this pairing is the pointed contour of the rear tire (long live the handiness) and the snake center groove on the front wheel.

And the way the rear tire looks after 300 km, it doesn't get old.
________________________

Greetings from the Rhineland

Et kütt like et kütt, et nothing necessary!

DER Christian (deleted)

30.08.2005 01:55
# 9 RE: Flutter at high speedreply


We are talking about the Metzeler Z 6 ??

So..

I drive it on an 89er 11er. Fork from White Power revised (damper changed + springs), strut from 11er Bj. 90, standard. Chassis set hard, also the damping. (I like it that way) Air pressure in front: 2.5 bar, rear 2.4 bar. Chassis also otherwise OK, steering damper from Team Metisse at the lowest level, actually almost only an alibi function.

My impression:

- Grip and stability, especially in a straight line, "like hell", the best I've ever ridden so far.

- Likes to follow longitudinal grooves, a third-class country road is enough, where the trucks left and right left their marks. But it's not tragic.

- Due to the stability when running in a straight line = a bit unwieldy in curves when turning. Needs strength.

- On the other hand, due to the stability in "funny actions" Very stable on third-class mogul slopes, country roads, little tendency to hit the handlebars.

- Wear: I will get over 6,000 km out of the rear, even after multiple motorway use and other "species-appropriate" Move.

- In my opinion, it reacts VERY sensitively to the air pressure, I have never had a tire that is so "bitchy" in this respect. With all the others you noticed a difference of 0.1 - 0.3 bar, yes, but the Z 6 really feels like a different tire. And until I had "figured out" the air pressure for mine, it took a bit at the beginning.

I'll buy it again, it's a great piece! Above all, the 6,000 km behind are convincing, the wallet laughs!


@ Godebi: Play around with the air pressure.


And now we have deviated "a little" from the actual topic.


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sepple (deleted)

30.08.2005 09:13

I don't think that this comes from the tire. Does your w still have the disguise?
sepple

Sven_GSXR750W (deleted)

30.08.2005 09:23

With mine everything is still original.

Steering damper only has an alibi function for me.

I think it's over.

Used as a replacement or would you rather treat yourself to something good if so, what and how expensive ???

DER Christian (deleted)

30.08.2005 09:35


The steering damper isn't, not at speed.

The only purpose of a steering damper is to calm the handlebar slap that occurs when you drive at full throttle over bumpy country roads and briefly lift the front wheel off the bumps and then touch it down again and then flutter briefly until it is back on track.


How much air pressure do you use to drive the Z 6? Try something to change there!

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gobedi Offline

Keyboard tormentors



30.08.2005 09:40
In response to:
We are talking about the Metzeler Z 6 ??

Funny that the impressions can be so opposite.

In response to:
- Due to the stability when running in a straight line = a bit unwieldy in curves, when turning. Needs strength.

Hmm, the behavior is exactly the opposite for me. It gets uncomfortable when the front wheel is apparently "light". Strong acceleration or straight ahead at top speed. A little bit of the gas, it's quiet. "Eggs" best describes the behavior.

In response to:
- On the other hand, due to the stability during "funny actions" on third-class mogul slopes, country roads very stable, little tendency to hit the handlebars.

I can confirm that. I don't have the handlebars slapping either (I still know that from the TL 1000).

In response to:
- Wear: I will get more than 6,000 km out of the rear, even after multiple motorway use and other "species-appropriate" movement.

Again, not. Looks more like 2500 - 3000 km here.

In response to:
@ Godebi: Play around with the air pressure.

Here I put my last hope on it. I filled the things in our company with 2.5 bar v / h. However, I was able to determine considerable differences from one tank to another, 0.2 bar seems to be a tolerance. So "relative" instead of "absolute filling"

@The Christian:

Have you noticed a trend in filling / draining?

Oh yes, I drive without a fairing = aerodynamics like a garage door


________________________

Greetings from the Rhineland

Et kütt like et kütt, et nothing necessary!

DER Christian (deleted)

30.08.2005 10:07


Yes. I noticed a trend.

The tire doesn't like low air pressure at all.

So it's better to drive / experiment with rather high air pressure.

That is true with the deviations of the measuring devices. I have my own compressor at home with a tire inflation gun. And according to the scale, for me it's 2.4 / 2.5 bar that I drive around with.


I have the impression that the Z 6 has a very stiff carcass, as it is actually intended for thick touring bombers with 300 kg empty + payload. And because of that it reigns bitchy compared to sports tires with a rather soft carcass. While the soft carcass still dampens the sports tire with "too little" air pressure and does not direct disturbances into the chassis, with the Z 6 I had the impression that the stiff carcass starts to "work" with too little air pressure, but is still stiff enough is to direct disturbances into the landing gear, and only with high air pressure is calm again.

However, this is only my amateur, subjective impression. Gut feeling and instinct. I am neither a tire nor a chassis specialist. The suspension specialists shouldn't tear me up in the air, but they can laugh themselves to death if I've written nonsense.

What does Metzeler himself say about it? Have you ever called?


With how much air pressure do you actually drive the Z 6 ???

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Sven_GSXR750W (deleted)

30.08.2005 11:47

Hi...

Now that I have changed the gas station (it was assumed that the air part is pretty good).
I checked the pressure there (2.3 instead of 2.5) at the front to 2.5 and at the rear to approx. 2.55.

Only had 20 minutes on the autobahn ... but only in the 160-190 range.
See no more rocking.

Gobedi Try it out ...

Unfortunately I don't have time to test again until tomorrow.
Since a van was so nice to ram me in front of the front door ... The pig. Parts won't come until tomorrow.

M.f.G Sven