Recycling 'The Legendary Motorcycles of Germany' since 1991
Steps are quoted literally from original instructions. Clarifying notes are added where necessary in green font. Send questions or comments to Kent Christensen #1681 at lkchris@osogrande.com
BMW made some serious mistakes many years ago in converting metric to English values in various of their publications. They admitted this. In BMW Motorcycle Dealer Bulletin (Vol II, No 23, dated 3/1982) BMW SAID NOT TO USE ANY PUBLISHED BMW CONVERSIONS FOUND IN BRACKETS IMMEDIATELY BEHIND THE MILLIMETER FIGURES, IN ALL SERVICE LITERATURE, INCLUDING RIDERS MANUALS, SHOP MANUALS, etc. This means that BMW meant for you to NOT USE published foot-pounds of torque, or any other torque value other than the metric. You can almost always TRUST BMW’s figures in Nm….although I recommend less torque, for such as spark plugs; wheel preload, ATU nut, alternator rotor bolt, and a few other places, with some special cautions on the flywheel (clutch carrier) bolts.
Are you thinking of purchasing a BMW Airhead motorcycle?? … have little or no or experience with them? Want some straight talk?
Motorcycles, no matter the age, all have a certain and specific feel to them.
For very modern bikes, a description may include high competence, plastic marvels, electronic marvels, …but not always having any special ‘character’. Special knowledge, & often special equipment, are often needed to analyze and repair them. It can cost $$$ at a dealership to do analysis & repairs. Those dealerships may be necessary for you when something ‘interesting’ happens; granted, the bike may …be more reliable over-all, depending on how you describe ‘reliability’. With a BMW Airhead, you can do most repairs yourself. Over-all, normal necessary scheduled simple maintenance is probably done more often with an Airhead. It is likely to be much easier to do …and there are vast amounts of history & knowledge easily available on the Internet, Mailing Lists & Forums, Club documents, etc. This is not so with the latest and greatest; nor, even motorcycles that are just a few years old.
Help is always available for Airheads from numerous informed sources. The Airheads were in production for a very long time (1970-1995); yet there are less than a handful of places, in all models, all years, that are well-known problem areas. Except for a few, all problems are fixable by YOU! The Airheads will require modestly more regular maintenance of certain things, but most often these things take little time nor cost. More modern machines might require less often maintenance, but the maintenance then required can be involved and often expensive. These are all big generalities, yes, but there is a lot of truth here.
The Airheads will not give you some things the much more modern bikes will, such as very easy starting in any conditions (due to modern bikes having electronic fuel injection), super brakes (modifications will, however), fancy suspension and ride controls, and probably more horsepower than you should have. But, there is no other motorcycle, of any brand nor type, that has the over-all character of a BMW Airhead, and most riders fall in love with them. The reverence with which some have for these bikes is legendary, and good condition examples of any Airhead model are fetching higher and higher prices.
The rest of this SECTION 1 was originally written by Greg Feeler on 07/07/2015, & posted to the Airheads LIST. The original Subject Title was “1971 R75 purchase questions”. I have Greg’s permission to add-to & edit freely, & I have done so. Because of the editing and additions, I have not put quotation marks in it.
This is by no means a complete list of technical hints for your BMW Airhead motorcycle. The Author’s website has well over a hundred technical articles. The Author’s website is:
HTTP://BMWMOTORCYCLETECH.INFO/INDEX.HTML
1. If you are trying to find out if your voltage regulator is faulty, or, bypass it in case of failure while on the road, and thus obtain charging; here is a simple method. I carry one of these ‘tools’ with me in my on-bike tool kit for testing purposes or on-the-road emergencies.
Obtain two each standard male spade connectors. Any autoparts store will have them. These may be called ‘disconnects’ or ‘push-ons’. Crimp or solder them to a stranded insulated wire about 6 inches long. To use; simply disconnect the plug from the voltage regulator under the fuel tank. Insert the male spade ends of your test lead into the plug’s female openings for D+ and DF; those are the OPPOSED openings. Do NOT connect to the female that has a brown wire. You’ve now removed the regulator from the system and ‘told’ the alternator to go to as high an output as it can…which it will at something like 4000 rpm or so. WARNING, this is for brief testing only or for limping home at low RPM. This is because riding any distance at high RPM will cook your battery and is also hard on the diode board, and every other electrical item. If your charging output is still low with the jumper connected, you have other problems.
For BMW vehicles, there can be confusion between the year of manufacture and the model year. This has sometimes caused problems with titles and registrations with various States. The actual “model year” motorcycle could have been produced near the end of the prior calendar year, due to the BMW company-wide vacation month in August and restart of production immediately after that vacation, in September. There are exceptions & anomalies …most of these are such as when a BMW bike was manufactured even earlier and mysteriously is identified by BMW as the following year’s model. This has happened with some Airheads and some Classic K bikes now and then. There is sometimes additional confusion, because, for 1984, BMW stopped stamping the last 7 characters of the 17 character VIN, always a 7 digit number, next to the oil dipstick of all engines.
For very considerably more information about VIN and Serial numbers, how to read all 17 characters of VIN’s, the sequencing, the anomalies, etc. see the following article: http://bmwmotorcycletech.info/IDnumbrs.htm
This article lists & describes, hardware items for BMW Airhead motorcycles & may have errors. It was not possible to physically look at every part listed here. Parts numbers & descriptions were taken from a Snabb Katalog & checked against a 1995 printed Parts List (the last such ever printed on paper by BMW). Most were checked against my own stock of parts; some were checked against on-line fiche. A small amount of input was from others.
BMW on-line fiche is not as fully descriptive as some other types of BMW parts literature. Most of you will use the on-line fiche, which is generally adequate-enough. Here is a good source of such on-line fiche: https://shop.maxbmw.com/fiche/fiche.aspx
Sometimes there are problems with spelling and/or sound, resulting in the opposite..or otherwise wrong meaning than what was meant. The German “Auf” is such a situation.
We usually order by part number or perhaps from a sketch or we describe where it goes/fits/etc. Almost all the time, this works quite well. Not always.
There are a few instances where languages have caused some serious confusion (besides politics and personal relationships!). There are situations where something is not described in your language properly, only in German, in literature pertaining to our motorcycles.
The above manual has been reprinted and is again available: http://www.crbmw.com/rokcart
The Electrics manual is $30. This manual is the best electrics manual for Airheads. Oak was primarily responsible for the manual. This manual is highly recommended by me, Snowbum.
My comments below are applicable to my copy which is dated 1993 on the front cover; and maybe to yours, if the manual is the same inside. Do let me know if your manual is not the same as mine ….when comparing my pages and notes, below.
Chemicals. Oils (not engine, transmission, driveshaft, rear drive). Assembly Lubes. Additives. Greases. Loctite. Sealants. Anti-seize. Electrical Contact Treatments. Waxes. Wheel paint. Tank Cleaning/Coatings. Windshield & Visor Maintenance. Other Cleaners
For BMW motorcycles, but with many applications to other makes.
This is not an article on pre-purchase-inspecting a BMW air-cooled twin motorcycle (aka Airhead, manufactured 1970 to 1995). Nor does this article contain information about how to prepare the motorcycle for sale. This is an article for a seller and purchaser about safety in negotiations and making a deal, test rides, handling a title, etc. The author’s website contains well over 100 articles on maintenance, but I do not necessarily expect you to read them prior to, for example, purchasing a motorcycle. If you are new to BMW Airhead motorcycles, I suggest you post an inquiry to the free Airheads LIST, for comments on things you should know about Airheads, and if you have a specific model (and perhaps year), or specific questions, that LIST is THE place for inquiries. Different years and models have specific things to know and be aware of. You may join the LIST here: http://lists.micapeak.com/mailman/listinfo/airheads
