You want to use a spacer that gives you 1 to 2 inches of sag.  I prefer close to 2".

NOTE!....the rear shocks come with adjustable spring perches.  That adjustment is not to stiffen the shock, but to level the bike....but, in effect, what you are doing is to set the rear SAG.   It is a crude way of compensating for loading, where a different spring would be the better choice, if needed.   About 20% of rear shock travel is plenty enough.  Most will do nothing more than adjust the shock perch stiffer for use with a passenger.  Some rear shocks have adjustable bound or rebound, however.  Follow the manufacturer's information on them.

Sidecarists:    The same adjustments apply for front and rear....unless you have a leading link front end....then, there is a lot more to know....and I do NOT get into sidecars in THIS article.

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 re-grease steering head bearings, they simply replace them. The reason is labor costs, if the cleaning and re-greasing then shows the bearing to still be poor in feel.  YOU don't have that labor cost limitation, right?

In a SHOP situation, labor is THE expense for the customer, and having to clean, assemble, adjust, and then find out that the bearings are still notchy...can be a waste of time &, thereby, customer money. In a home situation, with you doing the work, it is only another hour (two at the most, including doughnuts and coffee breaks) to try cleaning, inspection, relubrication, partial re-assembly and preliminary adjustment. If you then find the steering notchy, you do not have all that much work added to then just remove the front end, because you have only retightened the top adjustment nut for a check...no need to install nor tighten the top acorn nut, assemble the bars/cables, etc.

If you remove the top area, and the inner bearing, and look at the cleaned outer race, and see vertical marks: if you can feel them with a fingernail, REPLACE THE BEARINGS.

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 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 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 simplified adjustment. 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.  Depending on grease, time, and mileage, cleaning and re-greasings may be 5 or 10 years apart, in good conditions.

Do not use greases containing moly (molybdenum disulfide) compounds.   My experience with moly is that it does not work properly in this application.   Almost any light grease will be OK.    It is desirable to use a grease with good smearability, good water resistance, and particularly 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.   

EARLY Airheads, such as unconverted stock /5 bikes, used a somewhat different adjusting method for the adjustment ring just under the top triple clamp.   Many have converted them to the later non-split ring type.   The adjustment on the earlier type is done with a small diameter rod that is part of the tool kit, and is a slight bit of a PIA, but doable.
 

     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.

Here are 4 more photos, that may be helpful to you.  These are to give you ideas of various means to do the loosening and tightening of the center top cap and the fork tube caps, and the triple clamps, etc....so as to avoid or correct twisting, ETC.

The "procedure" continues after these photos.

 

This same squared-off end is
done to 27 mm or 1-1/16" sockets,
for the swing arm locknut. You can
use a short socket, as above photo,
for the front fork tubes' caps, and
with the wood piece as shown, the
cap can be hand-pressured so the
threads are not injured when removing
OR replacing the top cap.

A piece of bent pipe that is being used to apply torque in one direction, with the top triple clamp in place.
 

For torque applied the other direction:

    **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?, after all, you have the fuel tank off, right?  I suggest you clean the starter relay connections too, if you have the starter relay that plugs-in.

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 center-stand 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 an 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 aft
         and 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.
            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.

   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.    

 

   11.  Remove the upper bearing rotating part, 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.

 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 top nuts in place.  The usual reason to loosen, and later retighten, those lower triple side-clamping-bolts, is to allow the tubes to move ever so slightly, as you adjust the top bearing. Do NOT forget to tighten them after you are done.

 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.

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 for now, but tighten up the top triple plate at the fork tube 36 mm
         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 tighter than noted in this article; 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.    This is quite important for sidecarists.

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!  

     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.

    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???   

    11.  To adjust the swing arm, first insert the pivot pins (if not already), and tighten very lightly with an
           allen wrench (NOT a torque wrench), and go back and forth between the left and right pivot pins
           until the spacing from the swing arm to frame is approximately the same, as seen with your
           eyeball, or using a drill shank or small allen wrench as gauges.  Approximate is OK for this first
           step.   This approximately centers the swing arm in the frame.  Install the locknuts (if not already)
           with your fingers or the modified 27 mm or modified 1-1/16" socket (see below on the socket
           modification. The nut should NOT be tightened, but maybe a couple turns loose. 

          Torque ONE side pivot pin allen (hex hole) clockwise to 15 ftlbs. Back off from the 15 setting
          maybe half a turn, then re-torque IN clockwise movement (only) to 7-1/2 ftlbs. 

          Check the spacing from frame to swing arm. See if it is the same, left and right.  If not, back off
          one pivot pin & tighten the other.  Remember, clockwise movement during the tightening to 7-1/2
          ftlbs.  When the spacing is the same, then tighten ONE of the locknuts to 72 ftlbs of torque.
          Recheck the spacing.  If still OK, then torque the other side's nut to 72 ftlbs.  If the pivot pin
          and nut threads are in good condition, the tightening of this fine threaded nut will NOT cause the
          pivot pin to rotate during the 72 ftlb torqueing.  If you are worried about that, put a mark on the
          pivot pin face and associated frame opening, so you can see if the pivot pin moved after you
          tighten the nut.

          The final step is to force grease into the hex holes with a rubber tipped grease gun.  I prefer to
          force enough into the bearing, and out into the area between frame and swing arm, to have to
          smooth it into a ring of grease, with my finger tip.  This will keep water and dirt out of the bearing.
          Grease the same way every now and then.

           The socket:  You can use a 27 mm or 1-1/16" socket.  The socket MUST be modified by grinding
                 the END so there is no taper on the inside, as the 27 mm nut is thin and you do NOT want to
                 injure the nut.  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. To explain that further,  SOME bikes have a second circular
                 "ridge" inside the swing arm hole, so the socket must be ground on the outside.  The very
                 nicest way to modify the socket is to chuck it in a three jaw chuck on a lathe.  The entire job
                 can be done very neatly on a lathe in 5 minutes.

    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 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!
 

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.

Be my guest in trying to figure out why there are two specifications.

It IS possible to modify the dogbone wrench to enable an inch-pound wrench to be used.  Yes, use above figures and multiply by 12.
I have tried using a torque wrench, and it does work out OK, but not as good as with road testing and adjustment from those road tests.  I also have found that since the cables are almost certainly not going to be disconnected, nor wiring disconnected that all have an effect on the steering, that about 4 ftlbs was about correct.  It is tricky.