Do I need new steering head bearings?

[AndreP]

BMW K75 RT… The bike originally when bought had a head shake upon decelerating especially from 60-50 and when the bars were unweighted. The owner said it needed a new steering head bearing but there was no notchiness while moving the bars lock to lock. I replaced the front wheel and tire, tightened the steering head bearing adjustment (by maybe 60 degrees), realigned everything, and put on a new (to me) rear shock. The bike has a top box. Now I have eliminated the shake but there is this unsettling weave. It’s as if the front is moving around on its own separately from the bars, sometimes feeling like it is being blown by the wind. Furthermore, there is a crunchy, shakiness while leaned over. I have the bearings but I’m just checking if this sounds like the correct diagnosis? The bike has brand new Bridgestone battlax bt46 front and rear inflated to 32.5 in the front and 36.5 in the rear. Not an urgent matter the bike is certainly rideable I just can’t access all of its potential right now. The brakes have an intermittent light screech when not in use and now the front will occasionally whistle like a tea pot, is that normal.
Thank you,
Andre

[Duckbubbles]

The steering head bearings may be a little too tight now.  Try backing off the adjuster slightly and see how that works. 
Too tight bearings show up at low speeds as a constant back and forth corrections to maintain a straight line of travel.  Also at higher speeds and a weave back and forth rather than straight.
Once adjusted try raising the front wheel off the ground and and check for notchiness again.

Frank

[Chaos]

agree about being too tight can cause it to weave, hard to judge tightness sometimes because of the silicon dampener K75's used.

[AndreP]

I don’t really know how to judge steering head bearing tightness at all. I used a chisel and hammer to turn the dial/collar/nut thing. I’ll back it off this Sunday and get back to you guys afterwards. Thanks for the help so far!

[Laitch]

I don’t really know how to judge steering head bearing tightness at all.

I've used these instructions from BMW's workshop manual—p.00-43, downloadable from this site—during the 65K miles I've owned my Brick, and the results have been satisfactory. Of course, I don't have BMW's lift; the Brick is on its center stand and a hydraulic jack with a small 5/8" thick board on top of its piston is beneath the forward part of the oil sump to lift the front of the moto until its wheel is raised enough so the fork will move to lock position on either side of the tank without the wheel's touching ground. Verify the moto's stability before working on it.

[AndreP]

Ok so I backed off the adjuster according to the instructions. Unfortunately, it did not help. Still there is no notchiness when turning the bars, no looseness when someone holds the front tire and I try to turn the bars. I think the key to diagnosing this lies in the crunchy, wobbly left hand turns. With the now slackened head bearing adjuster it feels as if the bars want to twist left when I hit a bump. I had the forks off a few weeks ago, the left one (clutch side) didn’t rebound as strong as the other. I assumed it was a damping leg and the other mostly rebound.

[The Mighty Gryphon]

How does the bike steer at low speeds?

My K100RS did not feel loose, tight, or notchy, but part way into a low speed turn would suddenly turn in just a bit tighter.  I tried tightening the steering head bearings, but the improvement was marginal.  The problem went away after I replaced the bearings. 

[AndreP]

I have a parts bike that, when all together, rode straight as an arrow. Tomorrow I will swap forks so I can see if it is the forks or the bearing.

[AndreP]

I have to take a hiatus from this current fix. I’ve been side tracked. Showed up today to a puddle of gas.
Leaking from this… it has no gasket, does anyone know its name?

[Laitch]

You're pointing at the base plate of the fuel level sender. The circular stamped area on the plate is fitted with an o-ring within the tank. If that has deteriorated, or its mating surface on the tank has corroded, fuel will leak. Photos from Euro Motoelectrics.

[AndreP]

Gas tank is all set..
Bearings look good to me…

[AndreP]

Diving into the clutch side fork now
Isn’t this spring supposed to be oriented the other way around? With the tight coils on top near the bars and the loose down low? Pictured is the relative direction it came out to the top of the leg

[Laitch]

It will work correctly installed with the tight coils in either direction. Install it in whichever direction gives you confidence.

[The Mighty Gryphon]

Install with the tight coils down.  It will lower the center of gravity 2/10,000ths of an inch.

[sooprvylyn]

Install with the tight coils down.  It will lower the center of gravity 2/10,000ths of an inch.

every little bit counts:P

[AndreP]

So here’s where I’m stuck. The head bearings are fine. The axle passes the test with everything besides it tightened, methodically at every point tightened and untightening and readjusting to pass the axle test. I still have a shake leaning left. Wheel bearings seem fine, old but fine. And this is the second front rim, so unless both rims were bent then it’s not that either. The forks are fichtel and Sachs/ brembo S type.

[Laitch]

The head bearings are fine.
Wheel bearings seem fine, old but fine.

Steering head bearings can be too worn without being notchy. Was fore and aft play of the fork assembly checked?
How did you inspect the wheel bearings? Just looking at them while the wheel is installed isn't sufficient inspection.
How were the wheels balanced after the tire was installed?
It's possible to have a defective tire.
It's possible the Brick was subject to a minor front or rear impact that has affected frame/wheel alignment.

[AndreP]

You were right! The bearings themselves had some play. Well I certainly got a lot done on the bike this time. Steering head bearings, fuel pump and filter, fuel float gasket, rebuilt forks, and a spot on alignment.