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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: conybeare on May 27, 2011, 07:11:21 PM

Title: Adjusting steering head bearings
Post by: conybeare on May 27, 2011, 07:11:21 PM

I just replaced the steering head bearings on my 1990 K75S and they promptly went out of adjustment. After installing the new bearings, I adjusted them as indicated in the shop manual (with the forks removed) and had no problems. For the first hundred miles or so, it worked great with no play. After a few hundred miles, they loosened up and now I've got play. I went to adjust them (with the forks in), and no matter how hard I tighten the knurled nut, the handlebars swing easily from side to side. In other words, the knurled nut won't turn any further even though the bearings clearly aren't tightly pressed together. It's puzzling and driving me nuts. Just spend 15 minutes on the phone with the head tech/owner of a local BMW shop and he had no clue. I loosed the fork pinch bolts, the nut, etc., and no dice. When the forks were removed, I was able to adjust it properly, although the tech I talked to says it should be adjustable with the forks in.

Any ideas?

Kudos to Drake and Co. for starting this forum!

Title: Re: Adjusting steering head bearings
Post by: frankenduck on May 27, 2011, 07:20:15 PM

Get some big-assed channel-lock pliers at Harbor Freight to turn the knurled nut.  Worked on my K1100LT.

Title: Re: Adjusting steering head bearings
Post by: conybeare on May 27, 2011, 07:28:43 PM

I tried that already and it doesn't help. It allows me to tighten the kurnled nut just a tiny bit more, but the problem remains: the handlebars still swing easily back and forth...

Title: Re: Adjusting steering head bearings
Post by: frankenduck on May 27, 2011, 07:59:03 PM

Are you loosening both the hex nut (#5) and the bolt/plug thing that it locks?  (#4)

(http://i1221.photobucket.com/albums/dd470/Motobrick/kupperfork.jpg)

Title: Re: Adjusting steering head bearings
Post by: conybeare on May 27, 2011, 10:05:54 PM

Yup - I'm loosening both of those...

Title: Re: Adjusting steering head bearings
Post by: CubPilot on May 27, 2011, 10:40:25 PM

For what it is worth.   1994 K1100LT, took mine apart just because I was there, I already had it all apart to repaint.   Bearings were in good shape so I just cleaned the old grease out and repacked them and re-assembled.   After about 4 hours over two days anger took over and I took a block of wood and a BFH (3 pound hammer) and waled the hell out of the bottom tree and it was like Viagra, stiffened right up. Took two good wackes.   I like just enough tension so that the front end will not swing by itself.    Have about 1500 miles on it and it is still good.   I tend to get a little flustered when mechanical things don't do what I want.

Title: Re: Adjusting steering head bearings
Post by: mystic red on May 27, 2011, 10:46:00 PM

Quote from: CubPilot on May 27, 2011, 10:40:25 PM

For what it is worth.   1994 K1100LT, took mine apart just because I was there, I already had it all apart to repaint.   Bearings were in good shape so I just cleaned the old grease out and repacked them and re-assembled.   After about 4 hours over two days anger took over and I took a block of wood and a BFH (3 pound hammer) and waled the hell out of the bottom tree and it was like Viagra, stiffened right up. Took two good wackes.   I like just enough tension so that the front end will not swing by itself.    Have about 1500 miles on it and it is still good.   I tend to get a little flustered when mechanical things don't do what I want.

I like that method! ;D

Title: Re: Adjusting steering head bearings
Post by: frankenduck on May 27, 2011, 11:28:56 PM

Used appropriately, the BFH approach is good therapy too. ;D

Title: Re: Adjusting steering head bearings
Post by: conybeare on May 28, 2011, 12:47:19 AM

CubPilot - I'm assuming you were having the same issue as I am when you decided to start hammering the bottom triple tree - is that right?

Title: Re: Adjusting steering head bearings
Post by: CubPilot on May 28, 2011, 05:15:47 AM

Well, It kinda sounded like it.   I had taken my back apart twice kicking my self all the while that I had screwed it up and I could see nothing wrong either time.   Taking it apart is a PIA.  By the time I got to the BFH, my mind was telling my body tighten it up or really screw it up good.   There are some aircraft steerable struts that have to be assembled in a press to be able to get enough of the right pressure on the cones.   The top bearing on my bike was not a slip fit.   I had to cobble together a puller to get it apart.   I used some emery on the shaft to try to loosen it up and on the bench I could push it down but had to use a puller to get it back off.  But on the bike it just was not going to go.

Title: Re: Adjusting steering head bearings
Post by: conybeare on May 28, 2011, 12:12:37 PM

OK - I get what you're saying about needing a press to remove the bearings (I actually just took the steering stem assembly to a shop to have them remove and reinstall), I just don't understand why you would need force like that to press either half of each bearing together once they are fully installed and on the bike (with the races installed, too).  Or for that matter, what exactly hitting them does to "stiffen them up," as you say.

In any case I'm trying the wood/hammer method ASAP today! If that doesn't work I'm removing the wheel and forks since adjusting it that way seemed to work the first time around.

Title: Re: Adjusting steering head bearings
Post by: CubPilot on May 28, 2011, 12:49:56 PM

The knurled nut at the top is supposed to apply the pre-load to the tapered bearings.   I was apprehensive at putting that much torque on it to move the bearings I had a chain wrench and a 18" piece of pipe and could not get it to load the bearings.   So, as a last resort I applied a little bump shock to try to get the bearings to move together.   After the second whack the tension on the knurled nut was relieved somewhat and the steering head had what I considered to be about the right drag.   I backed off the knurled nut and re-torqued it to about 30 ft. Lbs.   There is an issue with either the shaft or the inside of the top bearing race.   Both bearings and races showed little to no ware and I really didn't want to replace them.   Out of curiosity I just went out and attached a load scale to the handle bar and it takes 1.6 to 1.8 lbs. at the bar ends to move the front end with the front tire off the deck.   These bearings are tapered rollers and by design are capable of a considerable load.   If I were to be replacing the bearings with new I would drop the rollers in a pan of hot oil for 15-20 minutes.   But not having new bearings they may have just slid home..??   I really don't know how they should feel.   Generally Tapered Rollers are not a press fit, only the cup is a press fit.  Hope this helps, I'm not good at telling someone what comes to me from years of experience of pulling wrenches.

Title: Re: Adjusting steering head bearings
Post by: conybeare on May 28, 2011, 06:36:24 PM

Quote from: CubPilot on May 28, 2011, 12:49:56 PM

I was apprehensive at putting that much torque on it to move the bearings I had a chain wrench and a 18" piece of pipe and could not get it to load the bearings.   

This convinced me I just needed to tighten a little harder with the BA channel-locks. Sure enough, that did it! I was able to tighten them quite a bit more (way past where I had tightened them previously - I had stopped because I was also apprehensive about using that much force) to where I could get the bearing snug enough.

...so I guess psychoticwaterfowl was right all along!