Cleaning and Lubricating Steering Head Bearings
 Adjusting the swing arm bearings.  Avoiding fork tube twisting.  Included is an in-depth discussion of STICTION and ALIGNMENT.

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 steering.htm-42

 

For information on replacing the steering head LOCK, see:  locks_caps_etc.htm

***NOTE!.....for longest steering head bearing life, you must not only clean and re-grease them now and then, but it is a GOOD idea to move the steering from full left to full right, to help redistribute the grease;....I sometimes do that sometimes when I park the bike!

It is advisable to read this procedure completely through before beginning.


The exact procedure varies with the bike model and year....different fitments at the top triple are the primary differences.

In the February 2003 issue of AIRMAIL, 'Oak' Okleshen, in an article entitled "Tank Slappers (from the Airlist)" succinctly identifies and discusses weaving and the high speed diverging wobble called a tank slapper.  He also states his method of adjusting the steering head bearings.  That is a read that I RECOMMEND.

See the following URL for a complete and extensive procedure on how to get silky smooth fork operation.  While not part of this cleaning and lubrication and adjustment procedure, it tells specifically how one eliminates stiction, and gets proper fork feeling and handling.  The GOLD STANDARD for fork alignment.

http://w6rec.com/duane/bmw/fork/title.html

Some of you may be intimidated by Randy Glass' article on Duane Ausherman's website, about aligning forks.  It IS comprehensive, and detailed, but don't be overly intimidated....it is not a difficult job.  Randy's article, which was written as he worked on his BMW Airhead, was written a rather long time ago, and is/was so good, I never wrote one like it myself, I just refer folks to it.    The photos really tell what you need to know if you wanted to get into it in depth.  But, whether you do a complete job like Randy spells out; or not... it is good to know what the proper and best procedures might be.   Most will not have forks that are in need of the full alignment...but most could be improved by that full alignment.  Reading the article will let you know what CAN be done, HOW it is done, but you will see as you read the article that some much simpler checks may well be all that you need.  You will also see by example and photos what the very important reverse-torque method is, to avoid twisting your fork tubes.

What I am going to say in this article applies to most motorcycles with older-style conventional telescopic forks.  It is especially so with the smaller tubes and triples that are not quite thick and beefy.  The smaller the thickness, the easier it is to twist or warp them.   Many top triples are plates of some sort that sit on top of the tubes. Some are clamping types, some have machined recesses, etc.    The more mechanically secure and sound types are less conducive to letting the tubes twist.     Many a motorcyclist has ridden with a front fork that has a steel or aluminum flat plate as the top triple, and is quite surprised at the improvement in handling from installing an aftermarket top triple that grips the tubes and is very precisely and ruggedly made.   Due to the forces from the wheel, at the end of a long lever (that lever is the long tubes, etc.), the forces at the top triple can be rather large...yes, right on up past the lower triple (which is often very much beefier than the top triple). Few folks install a beefed lower triple clamp, as usually the lower one is quite sturdy as stock.   Some of us old-timers remember obtaining an extra lower triple clamp and using that LOWER triple clamp, modified a bit, as a top triple clamp.  Can be a bit ugly sometimes, but quite effective.   Aftermarket beefy top triple clamps are available  for many motorcycles, but some are poorly machined and can make things worse.  Some are wonderfully made.  Some require a bit of ingenuity and work to make them fit properly....such things as headlight mounting ears, or? may require modifications, etc. 

Sometimes folks are surprised at how handling improves with a stiffer top triple as opposed to a flat plate; AND.....as opposed to adding some aftermarket fork brace, perhaps.    I should, in all honesty, state that the motorcycle manufacturer may well have a somewhat 'bendy' top triple ON PURPOSE, to have a certain FEEL, which is part of the over-all chassis design.  But, for crisp taut handling, a stiff top triple clamp is quite helpful; whilst most fender or fork braces do not very much.


NOTE that twisted front ends are mostly the habitat of conventional telescopic forks....and such as leading links have almost no similar problems.

It is rather easy on most of these telescopic forks to adversely twist the tubes in relationship to each other.  That can mean the tubes are not parallel to each other; or, are twisted the other way, or both. A cursory glance at the top and lower triple may make you think this can't happen without actual bending of the tube itself.   NOT SO.  It takes almost no movement of the tubes in the triple clamps to make the tubes, much lower down, be UN-parallel, or moved for and aft in relation to each other.  Also, keep in mind that the top and bottom triple clamps are NOT tied to each other EXCEPT by the tubes, and, thus, CAN be twisted, usually this means in the horizontal plane with reference to each other, BUT, in a few instances, the triples themselves have been bent.

The primary problem.. tubes twisting in relationship to each other.... can come about from failure to prevent this from happening when loosening and tightening the center nut or tube nuts, at the top triple clamp.  It also can come about from faultily installing the axle; or fender brace or fork brace.  I can't tell you how many times I have found improperly installed braces.

There is a relatively easy test that works pretty well on many of these forks, that requires no special tools, instruments, etc.

This is how it is done in general terms:
Remove the front wheel.  You may have to remove the brake calipers on disc braked bikes. Unfasten the top tube nuts or whatever they are, and remove the springs. YES, the central nut on the top is still there and tight.  Reinsert the axle, oiled, but don't tighten it ...that means no clamping, no axle nut,....whatever.  If the axle does not fit smoothly, clean it and do what it takes so the axle fits easily and smoothly.  Put your one hand on each lower fork assembly, and slightly move the lowers towards each other, and away from each other.  With a nice slippery axle you should see some movement...you do NOT need much force and do NOT want to use much force.  Find the approximate center of the movement, and leave the lowers at that point. LIFT at the axle....so the lowers, with axle inserted....moves upward.  Take it pretty close to the maximum upwards movement. If the stiction is high, you have a problem to investigate. The first thing to try is to unfasten any braces, and retry this procedure.  If the stiction mostly disappears, you must work over the braces by bending or washers/shims, whatever is appropriate to YOUR bike.  If the stiction does not disappear, you need to get a pane of glass and maybe a dial indicator, and find out just how and how much the tubes are twisted. Once you fix the alignment of the tubes in the triple clamps; you can again check the above method; and then if OK, add a brace....sometimes we have to bend or shim braces.

***It is very important to understand that at every step in the procedures I outline here, you are advised to continue checking stiction, as you do your work.  What I mean by this is that if you do an initial check with the springs out, then, when you have the springs in and the spring caps back on (as, let us say, the next step), then REcheck the stiction.    There HAVE been rare instances of a bent top triple plate, or other hard-to see anomaly, so if stiction starts up when you do some particular step in the procedures, then find out why and fix it!

Aftermarket braces have been the cause for lots of stiction.  SOME aftermarket braces can NOT be adjusted.

On many bikes, even if the tubes and triples and braces, etc., are all assembled correctly, you can add stiction by not equalizing the lowers on the axle before you tighten the axle nut (some models) and/or fork lowers axle clamps.

A fork with light to moderate stiction will not respond properly to tar snakes and other road irregularities, and will ruin the good handling the bike had designed into it.    It is particularly annoying on irregular paved surfaces in moderately sweeping to tighter turns, because in the transitioning, the forces are somewhat sideways, and telescopic forks are lousy at handling sideforces....and stiction can get MUCH worse in turns.""

The steering head bearing is common type 32028, 28 x 52 x 16 mm

Swing arm bearings are 30203A, 17 x 40 x 12 mm; and are basically the same as MOST of the pre-1985 wheel bearings, which are 30203.  The difference is sealed versus unsealed.  Frankly, I like them UNsealed, at both places.  Every few years I remove the entire rear end, and hand clean those bearings.  If I am working on a bike and find sealed ones, I puncture the seal, or otherwise remove or disable it, so I can get proper greasing in the future from the 6 mm allen adjuster hole.

Cleaning and re-greasing the steering head bearings may eliminate "notchiness" that seems to indicate the need for new bearings and races. It is likely best to do this procedure soon after installing new, balanced tires, as road crown, squaring wear, and balance, will have an adverse effect on trying to make final on-the-road adjustments.    Shops do not clean and regrease steering head bearings, they simply replace them. The reason is labor costs, if the cleaning and regreasing then shows the bearing to still be poor in feel.  YOU don't have that labor cost limitation, right?

Cleaning and lubrication of the steering head neck bearings is not a difficult job, but if a bearing is found truly bad, replacing the bearings and outer races is much more labor intensive, as one must deal with fairings, brake components, cables, removal of the entire front end, how to remove the bearings, etc.

Contrary to some popular belief, our BMW steering head bearings of the tapered 'Timken' style may well last over 200,000 miles. If the bearings and their races are in good condition and properly greased  and adjusted, the steering will be light, smooth, without notches. Notches almost always, when present, are in the straight ahead position.  Greasing is critical for not only hardened grease problems, but for protecting the bearings from moisture, which ruins them.  The upper and lower dust cups help to protect the bearings.  You likely will not find out if the bearings are bad until you first try the cleaning and greasing and adjustment procedure. The differences between airheads is mostly minor, with  improvements after the /5 models in the parts used to adjust the bearings; and, later, changes in the top of the top triple fitments. Cleaning and re-lubrication is recommended every 30,000 miles, especially with the open non-faired models, and particularly if driven often in the rain. 

Do not use greases containing moly (molybdenum disulfide) compounds.   My experience with moly is that it does not work well over time in this application.   Almost any light grease will be OK. For best performance, it is desirable to use a grease with good smearability, good water resistance, and a low evaporation/hardening over time. I use Chevron NLG1 or NLG2 Ultra Duty EP, a red colored grease, available from a Chevron Distributor, and not your local gas station.  Typically they want you to purchase a small box of these grease gun tubes. This grease can be mixed with about 30% moly (or Staburags or Optimol) and used for clutch and rear end splines...but don't use that mixture at the steering head or other tapered type roller bearings; nor, for ball bearings.  The plain unmodified grease is also very good for automotive chassis and U-joints. BMW red grease is OK.   Generally speaking any thin non-fibrous grease will work.   

>>>****In past years I have recommended that you use a grease gun and a grease gun hose with needle tip, and that you might want to get a 90 degree adapter for that needle tip.  I also recommended removing the front wheel.  I no longer use those items, NOR remove the wheel, and I now prefer to do the greasing by fingertip.     I vastly prefer the thin-feeling modern greases.  Do NOT use old-fashioned fibrous greases, nor really thick greases.

 

 **In our society of sue-crazy individuals, the following disclaimer applies: I take no responsibility for this procedure, nor for any ineptness on your part, such as failure to tighten things!...etc.  Airhead Canon #8 (and others) applies! 

 

I originally developed and wrote this procedure using both a 1983 R100RT and a 1984 R100RT...YOUR bike may be somewhat different, but the basics still apply.

    1. Remove the gas tank. Avoid scratching the paint, especially watch for interference with the opened seat: the left front edge of the metal seat pan is not nice to your tank paint.  If there is a problem with interference, remove the seat.  With the tank removed, now is a great time to inspect wiring, nuts and bolts, perhaps even the starter motor, breather, whatever.   I usually recommend you service the electrical system contacts, plugs, sockets, ETC....even cleaning the ignition coil(s) at this same time you have the tank off.  Heck, service those fuel taps (petcocks).

     2. If you have a damper knob, remove damper knob center screw, remove knob, spring, plastic spacer. 

     3. If you have the BMW hydraulic steering damper, you will need to disconnect the forward, large end, at the fork adjustment area ball.  If you have a BMW fairing, you must first remove the small rectangular rubber plug at the fairing, you will re-glue it into place when all done.   Then rotate and remove the damper wire clip (the wire clip, if you are not familiar with it, is the same as used on the shift linkage of many models).    To remove the wire clip you must rotate it off the shaft where it is clipped to, then it will pull out of a tiny hole in the damper ball socket.   Do NOT loose that wire clip.  Pay attention as to where and how it fits.   DO NOT try to force the ball and socket apart if you have not removed the wire clip, you WILL break the ball socket.   Once the wire clip is removed, the damper forward ball socket will pull down off the ball. It might be somewhat frozen to the ball, you might then have to force it off with such as a screwdriver blad.  Push the damper backwards, so it collapses.    When reassembling this area, you should clean and lubricate the various damper parts, including oiling or moly greasing the ball.

     4. Remove the dress cover at the handlebars if you have one. Remove the instrument pod assembly if you have one, by first unscrewing the speedometer cable 'nut' at the cable/pod and then remove the cable.  Loosen only the 3 each 10 mm headed bolts holding the pod to its bracket.   You do NOT have to remove those three bolts.   While you are in this area, note if you have WHITE colored rubber vibration isolators.  If so, replace with the updated, probably BLACK ones, from your dealer, they will reduce instrument vibration and prolong instrument life.

    5.  Now lift up and remove the instrument pod from the bracket and remove the phillips type screw at the center of the pod's electrical connector, and wiggle out the cable/connector. Set the pod aside where you won't trip over it.   When reinstalling this cable, spray a small amount of contact cleaner-lubricant or silicone spray, into the contacts.  If corrosion is noted, remove the corrosion, as best and as neatest and carefully as you can, before using cleaner or spray.

    6.  Using a substantial sized hammer if you have to, and the BMW tool kit 36mm flat spanner (you CAN hit that wrench with a large hammer on its sides), and being careful not to damage the ignition module if you have one, loosen completely the 36mm top stem CAPnut.    This is a bit different on the later models.  Do NOT loosen the lower triple clamp clamping bolts at this time!
You want to avoid twisting the forks.  Here is a photo showing a method of using an anti-torque tool; shown here for the TUBE CAP, for TIGHTENING mode.  This same idea, photo courtesy and permission to use here, from Randy Glass ..see article noted above in http://w6rec.com/duane/bmw/fork/title.html  is used for loosening and tightening the fork top caps, and that includes the loosening and tightening of the center nut, an early style center acorn nut is seen in this photo, with damper rod coming up through it.   In this photo, a pin, you could use a bolt, is placed in one of the top triple clamp holes, and the right hand is tightening the right side fork cap; and the left hand is putting counter-torque on the fork, using the pin and acorn nut as pry points, the left hand pressuring in counter-clockwise direction.   This procedure is hardly known by anyone but professional Wrenches'.  By positioning your pin/bolt, and the pry bar (here a very strong screwdriver), in the proper hole and position, you can tighten or loosen either left or right fork tube top nuts, or the center acorn nut, without worrying about twisting the fork tubes in relationship to each other, which CAN happen, DOES happen, and ESPECIALLY if the fork is against its left or right mechanical stop.   Randy's article, on Duane's website, above, really should be reviewed by you, it is a world of GOOD information.  If the fork acorn nut and or top caps are quite tight (usually are, and tight is proper), you may want a friend to help you use the anti-torque bar or tool in loosening and tightening these items.

In the photo below, the screwdriver tip seems to be pressuring the large closed end wrench (also called the BMW DogBond wrench) on the right side, this is not so.   The photo shows the wrench and screwdriver for the TIGHTENING direction, but simply move the screwdriver to another position for LOOSENING.

 

HINT:  that flat spanner dogbone wrench can be put over the damper rod (on some models), or otherwise slipped over the cap nut (many models), and NOT have handlebar interference, if the flat end of the spanner is THINNED a bit.   Do that on a grinding wheel and DO NOT thin very much, and DO NOT take the temper out of the metal by getting it too hot.  With the spanner now able to fit, in almost every instance, it is seldom necessary to remove the handlebars from the top triple plate, nor even loosen them for steering adjustments.  For cleaning and regreasing, you do have to remove the bars, but still attached to the upper triple clamp!   

    **If you have not removed the ignition module (1981+) in a long time, cleaning and re-greasing it with heat sink compound... why not do this now? 

The bike must be jacked up a bit to have the front tire off the ground a couple of inches.  You can jack it at the front of the engine, or perhaps at the front exhaust pipe crossover.  The bike will rest on the centerstand and the rear tire.  How this is done is up to you, and it may vary between bikes depending on tire size, suspension components, condition of those components.  Some folks park the bike on a sidewalk, with the front end over the curb.  On a flat floor, a specific problem will usually arise if you have a ride-off center stand.  For such, I will usually jack the bike at the rear of the engine/transmission...or at the rear frame crossover...or the exhaust pipes (wood across them both) near the muffler junction.   I have also, depending on the situation, placed a goodly sized piece of 1" thick plywood near the center stand, lined it up with my eyeball, and with the bike on the SIDEstand, place the plywood into needed position, and then straighten up the bike and engage the center stand UPON the plywood. This works well on ride-off stand equipped bikes.  I have done all sorts of things to get the front wheel off the ground a couple of inches....on a few bikes with Reynolds RideOff stands, I have used  locking straps at the rear suspension, to squeeze the rear suspension down...I usually add such straps from the lower shock units eye, up to some place like the luggage rack center area,,,,jump on the seat, whilst tightening the strap.  The front wheel will now be quite far off the ground.    

Block the front forks from dropping down too much, with wood or similar under the tire, if you need to. 

    7.  Remove, being careful with that hammer on the dogbone wrench! (if you need a hammer), the 36mm hex tops from the top of each fork tube at the top of the upper triple clamp plate. USE the anti-torque method.   Be careful, use downward pressure, there may be substantial spring pressure here!  It is not necessary to remove the caps center allen head bolts, where you put oil into the forks normally.  With the left and right top caps removed, and the acorn nut removed, you can now lift the handlebar assembly and tilt it enough to clear the damper rod (if you have one) in the stem .  Fasten the handlebar assembly forward against any windscreen, etc. or however; using some padding and a long bungee cord wrapped around the windscreen...or just lay it forward, depends on the bike.  It is not necessary to remove the fork springs. 

So, at this point, you have a handlebar with controls and cables and top triple as a total assembly lifted off the stem, and a front end ready to be dropped an inch or more.

    8.  Now you can remove the adjustment nut that was under that capnut using the BMW tool kit wrench. Remove the dust shield.  /5 models and late models are a bit different, but reasonably self-explanatory.  /5 models can be updated with the easier to adjust /6 type adjustment ring, etc.  

    9.  You now must remove the block of wood or what ever, if anything, you had under the front tire.   A pull, sometimes a goodly JERK,  from below, on the forks lowers, will release them downward a tad (adjust wood under the fork as required). If need be use a piece of protective hardwood (not metal) on the top of the steering stem, and the hammer, and give this a decent whack. When the fork drops down, say a couple of inches, then adjust the wood block(s) below the forks to move the fork very slightly up. This is necessary as the forks will have to be wobbily-moved around a bit fore and afand sideways, during the cleaning and greasing operation, so you can get your cleaning rag, and finally your greased fingertips, into the lower bearing area.  The top bearing is right there and EASY to deal with. 

    10.  EXTENSIVELY AND THOROUGHLY CLEAN THE LOWER BEARING/RACE AREA.  Use lots of lint free rags. I prefer old pieces of cotton bed sheets cut into strips about 1-1/2 or 2 inches by maybe 12 inches, so as to wrap well around the bearing during the cleaning. Use a small amount of a solvent such as kerosene or paint thinner on the rag pieces. Do NOT use dripping wet amounts.  Clean as best you can the entire bearing, innards, the shell, and area surrounding. You should be able to rotate the entire bearing, and get a good cleaning.  Move the fork as required.  Then a final cleaning with a dry LINT FREE rag. Grease this lower bearing.  I use my fingers and a LOT of grease, forcing it up into the outer race and the bearing, rotating the bearing as required.  You can not, easily, use too much grease.  You will need to use some finger pressure to force the grease into the bearing; rotate the bearing, and push grease into it; and onto the outer race in the steering stem. Be generous with the grease, you will clean the area up after final reassembly.   NOTE:  If you have the hydraulic damper on your bike, this is a GOOD time to lubricate the plate/rack area that drives the ball when the damper is adjusted from the top knob.  You can put the knob alone back in place on the damper rod, and rotate the adjustment, and get some oil/grease into that plate/rack area at the very bottom of the lower triple clamp.    

Force as much grease as you can, all around and into the lower bearing, and leave a goodly amount in the stem outer race area.

   11.  Remove the upper bearing, clean it and the cup/shell/race area.  Hand grease the bearing, forcing grease throughout.   IF the bearing has definite roughness after cleaning, lightly greasing, and now rotating and visual inspection, you will probably need to replace the top and bottom bearings and races....BUT!...you MAY be able to just continue with this procedure and get reasonably decent steering bearing operation...so I suggest you continue.

There is no good place to put this note in this article that might not be confusing as to where it is in the 'procedure, so I have placed it here.    It is important that stiction not be introduced by your work, and any stiction minimized.  Very early on in this article I described a test with the springs out, and advised that as you reinstalled them and the caps, that you recheck stiction.   Depending on what you are doing to the front end of the Airhead, you may want to be testing for that stiction as you reassemble, during the steering head adjustment, during reinstalling of the fender or other braces and mounts and wheel assembly, brake, ...whatever, ...depending on what the various things you are doing to the bike.   Do NOT let excessive stiction be in YOUR bike!

 

REASSEMBLY AND ADJUSTMENT:

    1.  Put top bearing, shield cup, adjuster nut, etc., in place, lifting/blocking the fork upwards, then lightly tighten the adjuster nut, using the special hook wrench (or, whatever, depending on your model). Wiggle the fork as need be.  Attach the handlebar/top triple plate assembly.  You should now be able to attach the center top nut, or acorn cap nut, ETC., depending on your model.  If that cap nut has a ridge underneath that is to engage the hole in the top triple clamp plate, be SURE it fits into that hole in the plate.  Attach the fork top 36mm hex plugs/nuts with any washers. Doing this can take considerable grunt against spring pressure; it will help to use a screwdriver or? into the allenbolt recess to apply downward pressure. Do not cross-thread!

NOTE:  your bike may have a strange plastic spacer at the top of the springs.  That spacer is formed to fit to the cut end of the coiled spring, so be sure it is put onto the spring properly...LOOK at it, and see how it goes together.   SOME people use a piece of PVC pipe (or metal spacer) at the top to provide extra preload, we are NOT talking about that. 

HINT:  It is easiest to start the top hex plug caps with the wheel as low as it can go, yet high enough to enable a few threads to be engaged.  This means a minimum amount...three threads or so, of the center nut.  

 DO NOT FAIL  to loosen the lower yoke (lower triple-tree casting) allen bolts, that provide the clamping pressure on the fork tubes.   Do NOT loosen those lower yolk pinch bolts before having some top nuts in place.  The only reason to loosen, and later retighten, those lower triple side bolts, is to allow the tubes to move ever so slightly, as you adjust the top bearing.

 Be sure all is lined-up correctly and tighten the two 36mm hex fork tube plugs to a small fraction of a turn LOOSE from hand-wrenching tight.   No need for the anti-torque tool right now unless you want to;...you are NOT tightening to the limit.  I DO use the anti-torque tool, taking no chances here.

    2.  Tighten the adjustment nut, that is UNDER the top plate (late models are done differently), rather tightly, moving the fork back and forth to take up any grease spacing. Loosen, and retighten moderately tight.    BUT....you now have to tighten the top acorn cap, as tightening it will tighten up the adjustment of the steering stem....see later herein. You DO need the anti-torque tool for this, as the acorn nut, whilst not 100% tightened in this step, DOES need VERY substantial tightening, to remove the 'play' in the ADJUSTOR'S threads.  SO.....you need NOT make this the final tightening, which is QUITE tight, at this time; still, that center top cap must be rather tight.  Maximum hand effort is about right, using the dogbone wrench, and the anti-torque tool...and NOT with the forks against mechanical stops!.  

NOTE:  Most acorn capnuts have a ridge along its bottom, that MUST fit into the top triple clamp hole...be sure it does!...if you do NOT have that properly assembled, you will bend things!

The motorcycle should be on the center stand and the front tire not touching the ground, nor any block of wood, etc.  If the forks flop easily to one side, unscrew the top cap, tighten the underside adjustment, retighten the top cap.  Try to get the forks so they JUST won't fall to one side by themselves; move the forks lightly from stop to stop to distribute the grease better, and try again.  

    3.  Inspect to be sure that wiring, cables, etc., do not interfere with front end movement. Assemble everything except, generally, the gas tank and steering damper and pod. Leave the lower triple clamp allen clamp screws loose, but tighten up the top triple plate at the fork tube 36mm hextops.  You NEED the anti-torque tool.   

    4.  The motorcycle should still be on the center stand and the front tire not touching the ground, and NO block of wood, etc.

    5.  The first try at a final adjustment, for motorcycle, not sidecar use, should be to the point that the front end exhibits a SMALL amount of perceptible drag.   The only friction should be from stem bearing grease, a small amount of bearing drag, fork tubes rubber boots if you have those, and cables/wiring. Give a 'rap' on a handlebar end, using your palm. This should be of sufficient force to move the handlebar about an inch or more, but not go flying to the stops. The handlebar will probably tend to just barely reverse direction a TEENY amount, or not quite, after such a rap.    Another way of looking at this is that the steering, once somewhat to one side or the other from center, should want to not really quite fall to the side, especially if nudged.    You must temper this idea with friction from cables and the rubber fairing boots, etc.   It is a bit better to start from a bit too tight, as that will be seen as weaving at low speeds, and a heavy feeling to handling.   Your bike will vary SLIGHTLY from other Airheads, in this adjustment.  GENERALLY, the forks on such as the G/S and R80ST will tend to just fall almost all the way to one side, but not so on the RS, RT, and so on.   It varies some.

****Those with sidecars attached should set the steering head a bit tighter, and there must be NO tendency for the fork to continue to move towards the stops, or to fall to one side or the other after being nudged on a sidecar rig.

At this point, turn the bars slowly from fully right to fully left. If you feel roughness or a center notch, you need new bearings and races, so have a blue day!  

     6.  At this point, tighten the top 36 mm fork nuts and cap nut FULLY...as tightly as you can with your hand and the flat wrench, and then several tads more with the hammer. USE the anti-torque tool.    The center cap nut has to be rather tight, almost to final tightness.   You will notice that this capnut has a major effect on the adjustment nut setting, so loosen the capnut and readjust the adjustment nut, retighten the capnut....until conditions are correct, with how that fork moves when nudged.    

    7.  SO..... a final check,.... with the CAPnut tight, if you turn the bars one way or the other, from the straight ahead position, and nudge them, they should NOT QUITE fall very much, just a small amount.   Some may want it a bit lighter, have the fork JUST fall, almost fully or fully, to one side, but NOT too easily.  Those with no fairing boots will likely want it a tad looser.  A tad of friction is better, but if it causes more than a WEE bit of weaving at low speeds, it is too tight.

Special NOTE!....Again I caution against NOT using the anti-torque tool.......and do not tighten things with a big grunt, such that the fork is at full left or full right mechanical stop whilst doing that tightening.  It is possible to twist the forks out of alignment!  

    8.  Assuming you don't need bearings and races, NOW is the time to.....and you MUST!!.... tighten the lower fork triple clamp allen bolts (don't even think of forgetting this step!), and to do a thorough check-over, to be sure you have assembled everything and tightened everything, except assembling the hydraulic damper and instrument pod and gas tank.  

    9.  Assemble damper, pod, gas tank. Again check that all looks OK, no cables interfere with steering, etc.   If you have a fairing and are assembling the hydraulic damper, with those wire clip keepers, you will need patience, and likely a small inspection mirror. Grease those ball ends before assembling damper. Put a tiny amount of contact cleaner or silicon spray onto the instrument pod electrical plug contacts, and don't forget the screw that holds that plug in place (and do not over tighten it).

 AGAIN, recheck all those bolts, screws, etc.  You DID tighten the lower triple clamps? Fork tops?   Did not get any cables crossed over or in such a position that the steering is not free???   

    10.  The rear swing arm must be adjusted correctly. If not, the motorcycle will not behave properly during your test ride.  

    11.  To adjust the swing arm, assuming the swing arm is centered or approximately so already at the frame: loosen one 27 mm locknut maybe half a turn or a turn or so. Torque that side's inner allen to 15 foot pounds. Back off from the 15 setting, re-torque to 7-1/2 ftlbs, ending up as torquing clockwise to get this 7-1/2 setting.  Lock nut torque should be 72 ftlbs. The lockout is 27mm, the center Allen is 6mm. Recheck centering (I use a drill shank or appropriate size of allen wrench at the inside junction of the swing arm to the frame as a gauge).   NOTE that you can use a 27 mm or a 1-1/16" socket.  The socket should be modified by grinding the END so there is no taper on the inside, as the 27 mm nut is thin.  Grind the OUTside of the socket, and do this squarely!.... where it fits into the swing arm hole... so that the socket goes past any internal projections and then over the 27 mm nut completely and thoroughly.  SOME bikes have a second ridge inside the swing arm hole, so the socket must be ground on the outside a wee bit further.  If the swing arm is not centered, back off one adjuster, and tighten the other, and when tightening the other, again tighten in the clockwise direction until you reach 7-1/2 foot pounds.   Don't forget to tighten the swing arm adjustors locknuts.

    12. Inflate tires properly. Remove saddlebags, and any rear trunk if not too much a bother. 

    13. Road test without passenger (passenger weight can modify the effects you are going to be looking for). Saddlebags, top boxes, and fairings/windscreens for that matter, have a noticeable effect on high speed 'weaving', rather noticeable on downhill sweepers at around 85 mph. This high speed weaving is NOT the weaving we will be trying to adjust out!...which is low speed weaving, as it is normally thought of.

     14.  The first road test is for low speed weaving. Do this on a flat road, not uphill or downhill.  Don't do the testing in turns, unless you have a fine feel for it.   For ALL tests, the damper MUST be off! You will likely want to do this test at about 30 mph. Do NOT do it at 50+.  If your steering bearing adjustment is too tight, you will find the steering a bit heavy, a tendency to weave and not track smoothly, particularly in turns.    If you have this condition, remove the gas tank to protect it, loosen the top capnut (use the anti-torque tool!) and loosen the adjuster nut a small amount, perhaps a few degrees. Retighten the top cap (use the anti-torque tool!), put on the tank, do another test.  You do not have to loosen and then re-tighten the lower triple clamp bolts unless you make nearly a full flat (or more) adjustment change. Since the bikes top parts vary, that is 60 degrees meant here.   If you DO loosen the lower triple clamp bolts, in order to make a top adjustment, be absolutely sure you retighten them before you go riding! If things feel correct in the 20-40mph range, try removing hands from the bars and giving the bars a small hit one way or the other, at about 35 mph. Any tendency for an INcreasing oscillation is cause for investigating tire balance, tire condition, even wheel bearings, etc. Any slight oscillation (also called a wobble) should be damped out instantly with the hands back on the bars. If not, you have a problem!

High Speed tests:

I have almost never seen an Airhead with properly adjusted steering head, have a problem at high speeds.   However, it is possible, and things like large bar-mounted windscreens; bad tires, poor wheel bearings, etc., can cause problems.

    15.  High speed tests are not for the faint-of-heart. They are usually done by beginning at around 40mph and increasing in increments of testing up to about 90. Every 10 mph, take hands off bars and tap them a tad, and check stability. 

    16.  Airheads, particularly the old ones with two sided swing arms, have an effect called, among other names, Rubber Cow, or a hinged-in-the-middle feeling.  This effect is a weaving feeling, often pronounced on the RS and RT models with bags and especially with a large backrest/tour trunk, at around 80 mph+, in downhill sweeping turns.   The effect is noticed, however, at some speed.   This effect is primarily caused by wind effects on those accessories, and the not very stiff rear suspension and frame design, particularly the rear subframe.    BMW improved this with the single sided swing arm and further improvement is possible with better shocks, springs, and modifications to stiffen the frame (the modifications of welding tubes to the swing arm are generally not of much use).  Surprisingly, a good front fork brace can help a bit. So can, especially, a thick top triple plate.   Aftermarket top triple plates are available.   Some have modified lower triple's for this, some have doubled up on the top plate; those are not as pretty.  If your bike exhibits this uncomfortable weaving feeling at HIGH speed, particularly downhill turns, it is likely not the steering head adjustment!   NOTE that a stiff aftermarket TOP triple clamp plate will help much more than a fork brace (which are often not properly installed and CAUSE problems with stiction)..  

    17.  It is FAR better to have the forks very slightly too tight at the adjuster nut, putting up with slight low speed weaving, than too loose. The reason is that if too loose you MAY have a chance of a high speed wobble.    Once you have done this procedure and have the steering adjusted correctly, you likely will get it right the next time without having to do these road tests.   I suggest you check the steering adjustment, now that the bike road tests perfectly, by having the front tire off the ground, and nudging the steering each way, and thereby see, for YOUR bike, just how much friction and movement occurs.  The next time you do your steering bearing service, simply adjust for this same effect!

****NOTE: A word of caution here about high speed diverging fork oscillations/wobbles. Due to gyroscopic and other effects, the forces at speed are fairly high. If a serious wobble begins, and forceful hands-on-bars pressure does not diminish or eliminate the wobble, you may well have a SPECTACULAR accident.  If you have adjusted your fork steering head bearings correctly, any induced oscillation from the steering head bearings will be dampened easily. If your tires are road crowned, under inflated, way out of balance, etc., you can still have an oscillation problem. 

Approach road tests carefully, deliberately, in stages, that is, slowly increase the speed from one test to the next test.  Do not suddenly jump from a 40 mph test speed to 80 mph.

****NOTE:   I have sometimes been asked if the steering head bearings have an official preload adjustment specification.  YES, they do.  The factory uses a tool that allows a torque wrench to be applied to the steering head top nut area.  The factory specifications is, believe it or not, different for the drum and disc brake models:
For the drum brake front ends, the steering head is to be at 1.9 +-0.2 footpounds
For the single or dual disc brake front ends, the steering head is to be at 2.6 +-0.14 footpounds.
It IS possible to modify the dogbone wrench, or do some other thing, to enable an inch-pound wrench to be used.  Yes, use above figures and multiply by 12.

Final note: This procedure has been abbreviated in places and expanded in others. If you follow it, make notes for your own particular machine. The differences between airheads is mostly minor in the steering head area over the years. Yes, there are variances in washers, nuts, adjustments...split ring...etc....but the basics and what you want to end up with, are the same. Steering head bearing and lubrication should be done every 30K or so....OR, when you feel center notchiness. BEST to do it BEFORE such notchiness is felt.   Non-faired models ridden in wet weather may find the need to do this more often, hence the reason I selected a long life grease having great resistance to water.  Having steering head set much too loose will almost surely cause bearing damage and lousy handling.

Revisions:  

01/28/2003:  MAJOR re-write, to eliminate, but still show, removing of the front wheel, and adding information on RideOff stands, and much more....to make the overall procedure less time consuming.
01/28/2003:  same date as above.  Add note #1 at beginning of article referring to Oak's article in Feb. 2003 AIRMAIL.  Rearrange the order at the beginning, and identify existing note as #2.
02/02/2003:  Add note on steering bearing number
04/03/2003:  MAJOR re-editing of many areas for clarity and improving adjustment details; add note on sidecar use adjustment; remove almost all references to old methods.
04/30/2003:  Add reference to lock replacement and note on lock to lock upon parking; add link to Duane's website
05/13/2003:  minor clarifications; links
06/01/2005:  Add more bearing numbers
07/11/2005:  clarifications, minor
01/09/2007:  Obtain permission from Randy Glass to use his photo.  Edit this article extensively.
04/13/2007:  Add posting from LIST article I did
11/08/2007:  ADD factory preload specs.
03/13/2007:  Revise for clarity (I HOPE it is clarified!!)

 

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