And the results of my steering head adjustment test are....

[Shuriken]

ALMOST A FREAKING TANK SLAPPER!

Very helpless feeling when you are at 110 and she starts the death wobble! :bang head: She was rock solid up until the magic number (so rock solid that I got too comfortable) and then it got violent.

That was the result of tightening the steering head up just a tad.

The result of backing it off more than I started and she has a low speed weave...

Somewhere between the two is where it should be, so I almost have to assume the wobble is not coming so much from the steering head...

 

[rumblethump]

Leave the steering head tight and check adjustment on swingarm.

 

[naughtyG]

I did a lot of steering adjustment and still had problems, then I took it apart and realised that my bearings and races were totally shot! When was the last time you took a good look at yours and/or replaced them?

 

[vmax626]

That reminds me,
as long as my bike is down I need to check mine too.
<<Dave>>unk:

 

[naughtyG]

as a reminder, you can easily check the state of the bearings by jacking up and removing the front wheel, and removing the handlebars.

Once all that weight and the cables restrictions are gone, it's a lot easier to feel how smooth or rough the bearings are when turning the triple trees. Removing the fork tubes helps even more.

I know that because when I first did the bounce test with everything on I thought my (shot) bearings felt just fine, but once I removed all the weight it was very obvious that they were totally shot just by how roughly they moved.

 

[vmax626]

as a reminder, you can easily check the state of the bearings by jacking up and removing the front wheel, and removing the handlebars.

Once all that weight and the cables restrictions are gone, it's a lot easier to feel how smooth or rough the bearings are when turning the triple trees. Removing the fork tubes helps even more.

I know that because when I first did the bounce test with everything on I thought my (shot) bearings felt just fine, but once I removed all the weight it was very obvious that they were totally shot just by how roughly they moved.

How many miles did your bike have when you noticed how bad they were ??:ummm:
<<Dave>>unk:

 

[naughtyG]

How many miles did your bike have when you noticed how bad they were ??:ummm:
<<Dave>>unk:

Bike is an '86, and it had about 37k when I got it.

Almost killed myself on the first ride home when it started wobbling around 125 mph. It's a real scary thing, because the more you tighten your grip the worse it gets, and rapid deceleration is actually the worse thing you can do - almost guarantees a tank slapper.

 

[Shuriken]

Yeah. Next free hour or two I just may take the front end apart. I have some spare forks too, lowered 1/2" I think. Scared the hell out of me. When you brake, you just load the front end more, which seems to make the wobble worse.... somewhere around 40k miles also.

 

[naughtyG]

indeed. I went though *way* too many of these before I changed my bearings. Scared the shit outa me, but my love for speed made me go back for more..

Found out that the best way out is to try to lighten the grip on the handlebars (about as hard to do as pumping the brakes in an emergency) and slow down very very gradually while trying to shift as much weight as possible towards the rear. Somehow lightening the front seems to get it back on track..

Still scary as hell when you're doing 120 and it takes about 15-20 seconds that seem like lifetimes to get it back together, doing your best to keep believing you ain't dead yet!

 

[2stangs69-91]

After reading your post I was a little worried. Do to a bunch of wheelies at the track and just goofing around I re-adjusted(re tightened my bearings). I have already done the furbur fix so I just redid the bounce test and tightened it up about a 6th of a turn. But I got lucky it took away most of the shake and was rock solid at 130mph. Good luck on fixing yours.

 

[Shuriken]

I think my front rotors are a bit warped. I hear a clicking at low speed, which I think is caused by slight increased tension on the caliper assembly / pads. In my reading of the possible causes of speed wobbles, I have seen dragging brakes mentioned...

Found this site for BMW wobbles, but it was useful:
http://w6rec.com/duane/bmw/wobbles.htm

From this site:
http://wiki.answers.com/Q/Why_do_you_get_Motorcycle_speed_wobbles
"LOOSE STEERING HEAD BEARINGS KILL PEOPLE. Get them fixed immediately."

This has a scientific description of the wobble:
http://en.wikipedia.org/wiki/Speed_wobble

Still researching stuff. But one thing is for sure, I'm going to just have to go down the list from the beginning and check everything.

It's frustrating because I know my bike was dumped before I got it. It has been stated that front forks that are not true, tire rims slightly out of balance, head bearings worn, swingarm bearings worn, steering head bearings worn, incorrect tire pressures, worn fork bushings, improper suspension damping, improper torque values, etc... etc... can all contribute. On a bike that's been dumped or crashed, all of the above could be #!$!!!ed up.

A Harley site I looked at even stated that excessively lowered bikes could contribute more to speed wobble if the rear axle was not in a proper relationship with the swingarm and front axle, and that it was important that the motorcycle be level.....

And I was reading about how to react when a speed wobble occurs and there is a lot of speculation and varied experiences out there. The only common thing I saw about dealing with them after they occur (if you survive) is to launder or change your underwear..... Some like to hold on tight, some like to let loose, some increase speed and then use the rear brake, some do a throttle wheelie, but I found NOBODY who advocates using the front brake!

All I know is that a true wobble/slapper is scarier than hell no matter if you've experienced one before or not.