Lubing Steering Head Bearings on BMW Airhead Motorcycles
Cleaning and lubrication of the steering head bearings should be done at a scheduled mileage/time but most let it go until the steering has a 'notch' felt in the straight ahead position. This procedure was developed specifically for a 1983/1984 R100RT, but is similar for all Airheads. I advise you to read this procedure through before beginning. Cleaning and regreasing MAY WELL eliminate "notchy-ness" that SEEMS to indicate need for new bearings and outer races. It is best, but not mandatory, to do this procedure after installing new balanced tires, as road crown and tire squaring wear, and balance, might have an adverse effect on trying to make final on-the-road adjustments. This is not hardly just for the front tire....most riders do not know that a squared-off REAR tire is THE most common cause of wobble and weaving from the tires. The author has usually, but not always, done this procedure to his own bikes after installation of a new front tire, but when the wheel is off the motorcycle. If your REAR tire is not squared-off considerably, it will be OK for the final procedure, which are riding tests to get the preload adjustment 'just right'. It is possible to do this procedure with the front wheel in place, usually that means having the front wheel hanging over the edge of a curb, or the centerstand is in use and on a piece of wood, so the front end can be dropped a couple of inches.
Cleaning and lubrication of steering bearings is not at all difficult, but if a bearing is found truly bad, replacing them is more labor intensive, as part of any fairing must be removed, and possibly brake piping, cables, 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/races/shells are in good condition and properly greased and adjusted, the steering will be light, smooth, without any straight ahead notch. You likely will not find out if the bearings are really bad, that is, in need of replacement, UNTIL you first try cleaning and greasing. In a SHOP situation, the bearings are not cleaned and lubricated and then adjusted to see if any notch is gone. In a SHOP situation, labor is too costly for that. A shop can not take the time to clean and regrease, and then find out that the bearings really are bad, so a shop always replaces a notchy bearing. YOU, on the other hand, don't need to do that.....and will often save a LOT of money, and a considerable amount of labor saving is possible.
The general/generic procedure in this Technical Tip is adaptable. The differences between Airheads is mostly minor, with some improvements after the /5 models in the parts and method used to adjust the bearing. The /5 can have the /6 and later type adjustment parts installed. The last of the Airheads, including such as the R100GS, etc., had more involved changes in the adjustments, using a sleeve tool (which you can make for pennies) method of adjusting the bearings, and removes most of the need for on-road testing and adjustment.
I recommend cleaning and relubrication every 50,000 miles or 4 years, whichever comes sooner. Non-faired models (especially if driven in the rain or extremely dusty conditions often) may require more frequent attention. Do not use greases containing moly compounds, they do not work well over time in THIS PARTICULAR application, and will actually start to exhibit notchiness rather soon, as the Moly will clump-up.
Tools: Nothing special, but you will want a 6 mm allen wrench in drive size to fit your torque wrench and you will want a modified 27 mm or 1-1/16" socket. What you need is actually somewhat dependent on your particular model of Airhead, particularly the R100GS. The normal BMW bike toolkit will suffice for the rest. Read this entire article to see what YOUR particular bike will need.
Almost any thin-feeling, non-fibrous grease will probably be adequate. It is desirable to use a grease with good smearability, good water resistance, and especially low evaporation/hardening over time. I use Chevron NLG1 Ultra Duty EP, a red colored grease, available from a Chevron Distributor (most Chevron gas stations are NOT distributors, but you can ask if they have that grease). The last time I purchased some, it was available in NLG0,1, and 2. Do not use NLG0. The NLG1 or NLG2 are both OK, the NLG2 being a bit thicker. All are lithium based greases, with tackiness additives, etc. You can use this grease for many other places on your Airhead, INcluding transmission input splines (add moly), and it is very good for wheel bearings and the swing arm bearings. For the rear wheel cup splines (used on twin rear shock models), and transmission input splines or nearly any other splines application, I suggest mixing with about 30% moly (or Staburags or Optimol). If you wish to purchase a moly lubricant, the two I know best (besides military moly lubes which are fine) are