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View Full Version : Speed wobble question and video.



sugarrey
Sun Apr 12th, 2009, 08:46 PM
http://www.youtube.com/watch?v=XiKmPFo6xNA

Damn....

Also wanted to ask a question about speed wobble. Lately when I let go of the bars over 50 I get this "speed wobble" sensation. Now this has never happened before (as I use to let go for a second or so to rest my hands and such.) But it now happens everytime, what causes this?

Bueller
Sun Apr 12th, 2009, 08:54 PM
Tire wear and/or low pressure

Tipys
Sun Apr 12th, 2009, 09:01 PM
Steering Dampener FTW

brennahm
Sun Apr 12th, 2009, 09:03 PM
Check the tightness of your head bearings. Probably worn out/loose. If you have a stand that leaves the front wheel hanging then grab the bottom of the fork legs and shove/pull back and forth. Any play?

At the least (and this isn't hard) you should pull the top triple tree, rotate the bearings 90 degrees, relube, and retighten. This is supposed to be yearly maintenance.

rybo
Sun Apr 12th, 2009, 09:21 PM
Tire wear and/or low pressure

Very likely the cause. Be sure the check tire pressure before every ride. If you are seeing uneven wear on your tires (cupping) then they may be done, even if there is lots of tread left.


Steering Dampener FTW

Bikes should be stable without having to add dampers. Racers use them because in a race situation at race pace on a race track it is possible to induce a speed wobble coming off of a corner, at full lean while moving to full throttle. This should NEVER be a situation you find yourself in on the street. The bike has some other problem that is causing the wobble. Will the steering damper prevent it? Probably, but this is a solution that cures the symptom, not the problem.


Check the tightness of your head bearings. Probably worn out/loose. If you have a stand that leaves the front wheel hanging then grab the bottom of the fork legs and shove/pull back and forth. Any play?

At the least (and this isn't hard) you should pull the top triple tree, rotate the bearings 90 degrees, relube, and retighten. This is supposed to be yearly maintenance.

Also a likely cause of the problem. This can cause the cupping mentioned above.

guessinthe2000
Mon Apr 13th, 2009, 12:22 PM
All I have to say is the worst feeling ever. I was coming from Idaho(straight shot) to Denver. Had one hand on the right handle and hit some little crack on the road i got the speed wobbles. I almost shit my pants! Freeking scary!

TFOGGuys
Mon Apr 13th, 2009, 01:10 PM
Most decceleration wobbles can be traced to bad steering head bearings. More uncommon causes can include bad swingarm bearings, bad wheel bearings, and excessively worn chain and sprockets, although all of those will cause other symptoms as well.

Zach929rr
Mon Apr 13th, 2009, 01:31 PM
Kind of related... but I was watching/reading an interview with that rider on an Italian tv channel and his comments on the incident were that he tried to unload the front with throttle but he was already at the top of 6th. Can't believe he survived that.

sugarrey
Mon Apr 13th, 2009, 08:40 PM
I dont have the correct stands or tools necessary? Anyone willing to help (that has experience?) I do have a complete service manual.

Tipys
Mon Apr 13th, 2009, 09:19 PM
Ask Sean he will then call Rybo

Aphrodite
Tue Apr 14th, 2009, 06:12 PM
Also check rear wheel alignment, slightest bit off could cause it at higher speeds or coming out of tight corners.

Repsol a095
Tue Apr 14th, 2009, 09:20 PM
Most decceleration wobbles can be traced to bad steering head bearings. More uncommon causes can include bad swingarm bearings, bad wheel bearings, and excessively worn chain and sprockets, although all of those will cause other symptoms as well.

+1 for bad wheel bearings!!! I had this happen to me at Miller a couple years ago. I had a really bad head wobble, and it turned out that ALL of the bearings in the bike were bad.

I also had this happen on my FZ about a year later, and it turned out that the head bearing was loose. It is a pretty easy fix, but I would get some good advice before you do it yourself because you don't want to over-tighten it!!!:hump: