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and other numbers/characters identifications...
Serial numbers.  VIN (Vehicle Identification 'Numbers'). 
How does BMW identify the "year" of your motorcycle.

Copyright 2020, R. Fleischer

This article contains a large amount of information regarding vehicle numbers and identifications, most especially for BMW Airhead motorcycles, but much of this information also applies to other motorcycles (any brand), and even your automobile and truck.

You may be interested in the information in: and  Those two articles have further identification information.

My own very extensive listing of BMW motorcycles:
I suggest you come back to this link AFTER you read the rest of this below article.


BMW may use different frame and motorcycle identification systems for non-U.S.A. motorcycles. There may be a letter or two letters, followed by a serial number. There may be a serial number followed by one extra number, and then the type of motorcycle.  Seven (7) digits are used for the serial number. I do not know what the letters nor the 8th digit means, it could be a check-digit. The VIN system of 17 characters may be absent, in favor of just the Serial Number, with possibly a very small BMW roundel stamping and a letter or two or other number or two. This has especially been seen in later Airheads for ECE shipments.  The 17 character VIN system was introduced in 1980-1981.

North American shipments:
Before the all-brands transition to the 17 character VIN code in the 1980-1981 era, BMW used only a serial number. Simply  find the number on the engine & find the frame number, which were usually the same number.  For more information on the earlier old models, see Duane Ausherman's website:    Duane has some information on how the early model numbers were assigned.

For detailed information, and actual lists of pre-1970 serial numbers and models they are associated with, and even information on some shipments and owners, see   Click on FORUM, and then go to the VINTAGE section.  BMWMOA forums are limited to BMWMOA members.

See this:

In the seventies, BMW motorcycles were identified by the number stamped into the frame, as always, ...but the number was located for some time at the steering head, ...and depending on the model/year, it may be found on the right side downtube, or in front.  Later, the number moved to the right lower frame tube, roughly below the right cylinder.   Note that the frame number is the id number, whether or not there is one at the dipstick or on the flat boss of the engines from 1984, etc.  The engine and frame number prior to 1980 was 7 digits.  BMW made changes to one or two digits to identify the model, and the result was a grouping, in order, of serial numbers for that model.  In some fewer instances, two or three models were similarly done, sequentially, in the same grouping.

In 1980, the VIN system began phase-in. This system was, and remains, a 17 character Vehicle Identification Number (VIN), which is a combination of letters and numbers. At first, BMW continued to match the 7 digit serial numbers of frame and engine for the same bike; those numbers being the last 7 digits of the VIN.  Some anomalies for 1980-1982 production are seen, so if you have a production year 1980-1982, do not be upset if things look somewhat different. BMW continued to produce a few anomalies.

The early 17 character VIN numbers almost always had the last 7 digits correspond to the engine number as still stamped into the engine case at the oil dipstick area.  Stamping the serial number at the dipstick area stopped with the 1984 models.

NOTE:   As the new identification system phased-in, some foreign (NON-USA) BMW motorcycles had modified numbers style to conform ..sometimes partially, but not always, and sometimes just a code letter or two prefix followed by the old style serial number...but, many did have the new 17 characters method, but some got into the hands of owners without such modifications. This usually occurred with certain regulatory dates. Some of those transition period vehicles had not yet been sold and were in distributors warehouses.  For these non-USA bikes, it is entirely possible to find a motorcycle with a VIN identification plate mounted over the original stamped, etc., area...or, located someplace on the motorcycle.  This caused problems with motor vehicle departments in various U.S. States if later imported, and some State-specific identification plates may have been used to take care of that "problem".  You might see such a strangely  identified vehicle at some time.   Occasionally there will be a problem in transferring ownership, if the vehicle is "inspected" prior to a full transfer.  One particular thing you may see more often is a fairly large added silver glued-label, on top of the driveshaft housing.  In some instances that VIN 17 character identification will have a ONE year difference compared to the stamped frame number, and this situation was fairly common for 1983 BMW motorcycles, that still had the 7 digit serial number located at the dipstick.  This anomaly was much more common with California-shipped motorcycles.  A bit more on this, two paragraphs further down....and even more, even further down.

If the flywheel is removed (NEVER do that unless you FIRST block the front of the crankshaft to keep it from moving fore/aft), the rear face of the engine is exposed, and you can see casting information stamped (cast-into) the area.  Typically there is a 2 digit number signifying the year of manufacture; and that number is surrounded by 1 to 12 raised dots which signify the production month of the casting.  This has been particularly helpful for identifying certain changes; and, especially so if you have a 'replacement' engine block, not serialized.  Yes...some engine blocks for replacement purposes were made without any serial number of the type normally seen on the pre-1984 models, that is, at the dipstick area.  The dealership was supposed to transfer (stamp into the metal) the old engine's number, and destroy the old engine or ship it to the BMW importer/distributor.  Some dealers apparently did not have or did not use metal punches and there may be no serial numbers on those replacement engines.

Near the end of 1983, with the introduction of the 1984 model year motorcycles, BMW decided to not match up frame and engine numbers, and BMW eliminated the serial number previously stamped next to the oil dipstick. They said so officially, although BMW did produce some engines with the 7 digits stamped next to the oil level dipstick when BMW said they would no longer do that.   There have been a few widely-scattered reports of differing serial numbers on the same bike.  My guess is that BMW utilized some engines, frames, etc., that were in inventory during the transition period.  There are not many of these.    BMW also incorporated stamping a full VIN into the lower right frame tube. That stamping can vary with the particular Country the bike was shipped-to. There are some Countries that require special plates or stampings, and I will not be getting into those further in this article.

Per BMW factory bulletin 2298, if your State or Country requires an engine number, you are to use the top line characters on the milled flat area on the engine case, located below and forward of the left cylinder.   BMW meant (my interpretation) this applied if you did not have a stamped engine number located at the dipstick area.  The stamped milled flat area number BMW said to use is not really a true engine number, and all will be explained in this article.

Frame numbers were stamped at the right side of the steering head (or on a riveted tag located there) from 1970 to 1982. There were some that were not stamped.  Dates on the tag, if present, signify final assembly of the motorcycle.  Just what was stamped, tag or metal, if there, can vary.

If you have a stamping into the flat steel plate side support for the steering head, it may be only the serial number, not a full 17 character VIN.  There are also instances of frame replacement, that may have a standard BMW metal plate there, with new stampings, by other than BMW themselves.

Some 1981 and 1982 bikes did not have the full VIN stamped onto the frame below the right cylinder. The serial number was there on most BMW motorcycles.   There may be a silver sticker there, the serial number being just forward.  You also may see bikes of the early 1980's with a large silver-colored metallic label located on the top of the driveshaft housing.  These labels had machine-punched letters/numbers to identify the VIN number.  A few bikes, mostly those shipped to California for the "1983" model year, were stamped for either 1983 or 1984 by using the single letter ID in the VIN for the model year.  More on this later in this article, because it is a peculiarity ....I call it an anomaly ....because these bikes may have both 1983 and 1984 identifications on them!

On many BMW Airhead motorcycles as shipped to most areas, from ~1980, there is the previous-mentioned milled area with stamped-into-the-metal information that typically does not include the actual bike serial number as it used to be. This milled flat engine pad area is approximately 3 inches wide and 1-1/2 inches tall, and is located approximately below the left cylinder, nearly to the edge of the oil pan.  Not all engines had the milled flat area as early as ~1980, and I don't have all the information on that.  BMW's own bulletins are, or can be, faulty about this, particularly in the beginning year or two.    Where the milled-area engine pad exists (which it does on the vast majority of 1980's+ engines) ...were identifying characters, some not revealed to me nor usually anyone outside the factory; the official word (if there is such for this) is that it is for theft protection/information.

I have BMW's internal factory information (two bulletins) regarding that milled area, and in some instances BMW did not stamp information in the format as BMW said it would in that factory information.  I believe that BMW factory personnel probably mixed-up the order of year and week, that is, reversing them, in the stamped top line.  As you likely know, the Euro order for week and month is opposite that used in the USA.   This difference in stamping, from what BMW's bulletin to ALL dealerships said, was not consistently done, and eventually was fixed as to the proper Bulletin order.   Simply put, the result is that some bikes don't conform to BMW-published standards in this milled area.  There are two lines of characters, and as noted in the prior paragraph I cannot properly interpret the lower line for you.

The upper line will have the production year and production week, and a Serial Production Number. The exact meaning of Serial Production Number is not known to me, as to production line assembly of engine...(or, motorcycle?).   As I have noted, BMW was not consistent during the transition to the new VIN 17 character system and not fully consistent with identification information stamped into the cases, and occasionally onto the frame. One BMW bulletin was entitled "Decipherment of BMW VIN's according to FMVSS 115". That was a government document regarding the then new-fangled 17 character VIN number. Decipherment will be explained later in the article you are reading. BMW phased-in the VIN, and phased-in the stamping on the engine case milled area.  Although BMW irregularly phased in the removal of the serial number at the dipstick, and it generally happened for the 1984 model year, there were a few anomalies.

All the changes, that I have mentioned,  did not occur with all models at the same time or even within a particular model, which BMW never explained. Further, the BMW factory bulletin sketch and information on the upcoming changes mostly came to the dealerships after the changes were partially incorporated, and this dealer bulletin was not part of the normal Service Information series of bulletins. I have all this BMW printed information, and I am incorporating it into this article for you.

BMW said that the effective date for incorporation of the 17 character VIN was the model year change during 09/01/1980 to 01/02/1981.  September 1st (or, nearest work day after) is the day the Factory re-opens after the month-long vacation period (aka Holiday period). I have found all this to be typically true, but there are some anomalies. The dipstick area located serial number was not part of this dealer bulletin. A 1988 Service Information Bulletin, numbered 2298, pretty much repeated the then much older incorporation of the numbering systems, locations information, etc.

While all this is complicated, all you usually need to know is:
The week-year on the stamped area top line might be reversed to year-week, particularly in the 1980 to perhaps 1983 era.
The dipstick area serial number disappeared for 1984 and later.
How to interpret the 17 character VIN, character by character, is explained in this article below, if you ever need this information.

More details:

Keep in mind what I said about there being several stages in these various changes, & they did not occur all at the same time for all models, & there was a bulletin released separately & later than the original milled area information. This new bulletin was released in November of 1983.  It concerned the engine serial number that used to be at the oil dipstick area, and previously almost always was the same as the frame serial number.  BMW announced changes in November of 1983, via Bulletin 11 025 83 (2088).  This bulletin (which we call an SI, for Service Information sheet) said that BMW no longer matched engine & chassis numbers.  This, in itself, can be confusing, since BMW dropped the official engine stamping 7 digit number.  Further, BMW added the milled (machined) flat surface area, & the numbers identified the engine number, model year, week of production, & had a sequence number ...all these were on the first line (and, BMW was not, as previously noted, consistent with the week/day order).  This was not the only Bulletin, & some were revised, some not, & at least one bulletin was modified or re-introduced as late as 1988.

In my opinion the 1988 release was a quick and dirty way to help those who were having trouble titling or registering vehicles with some States' Departments of Motor Vehicles, whose personnel did not know, or did not understand, how BMW serialized vehicles. That is, there was no longer a very specific engine number (previously located next to the oil dipstick).  BMW, in my opinion, took the easy way out.  I do not think BMW followed up by informing all States of the Bulletin, thus leaving the information at the dealership level, to be given to Airhead owners ...not the best way to pass out information needed for State authorities/agencies, as owners might be unlikely to ask dealerships how to register their bikes (specifically, a used bike purchase, particularly with an out of State purchase) ...and for other reasons.   SO ....BMW decided to use an existing number located on the milled flat area!  That number was really a sequencing of manufacture of the engine (and perhaps final assembly? ... no one really knows that I have talked-to) ...and a factory production sequencing number might well not be a true serializing ...but since no two lines of numbers would ever be totally the same, BMW said the following:


BMW meant that, MY interpretation here, this applied if you did not have a stamped engine number AT THE DIPSTICK, a very rare event on any (if so, would be very early-on during these changes) motorcycles using the new method of identification.  Because of this information, it is fair to say that many, if not most, of the motorcycles not having engine dipstick area serial numbers, were titled and registered, if motor numbers are required, by a combination of engine production DATE, and a sequence number.

The second line on the milled area had EPA (Environmental Protection Agency) and other information.  BMW kept files on what all these things mean and some was for the National Automobile Theft Bureau for theft inquiries only.

There were other anomalies, in that some 1981 and 1982 bikes did not have the full VIN stamped on the frame rail below the right cylinder, but the serial number was there, and may be located just forward of a silver sticker.

Information I previously noted in this article, re-written: 
In BMW's original information sheet as provided to dealerships, see bulletin numbers, the top line coding was to be WEEK, YEAR, & then SEQUENTIAL CODING.  Some mostly early bikes were stamped with week and year reversed.  The SI very specifically said and showed sketched too, that it was WEEK first.   I have seen the reversal now & then. I don't have any official explanation, but believe it was from:  (1) unclear instructions to factory production personnel; and, (2) the errors occurred because not all countries use month or week first in how a date is written.

A few paragraphs below is a photo of an Airhead motorcycle's milled area.  The top line is  14 847395.    Production is 14th week of 1984.  Sequencing number is 7395.   Note that the week is listed first, as BMW said in its bulletin.  Other characteristics of this particular motorcycle confirmed its production date, such as not having a dipstick area serial stamping ...and a driveshaft tag had the E year, same as the stamped VIN, etc.  I have confirmed that this bike, not engine, was produced on March 1, 1984.   I have no specifics for the bottom line which includes emissions information.

For those finding the milled area in the below photo difficult to read:
top line:   14  847395
bottom line:  EBM  098042  A2

For the bottom line, the first letter "seems to" be the letter that is used in the VIN coding system for the official model year for the bike.  Above, that letter is E, and E stands for 1984.  BM "seems to" mean BMW.   This coding of year and BM is, however,  inconsistently seen.  The  098042 A2  I have been unable to decode.  I have looked at a number of early & later models without figuring it out. The bottom line of the milled area seems to be coding as to what sort of emissions, etc., equipment the bike had, etc.  As I have mentioned, BMW said it had the bottom line coded for internal company information for such as theft protection, sequencing, and possibly also emissions, etc.  I think, no proof, that at some point the bottom line no longer had a specific identification for the specific motorcycle, but became the engine family or emissions identification.  No longer would that bottom line identify any specifics for an individual bike for theft, etc. (??).  For example, my own 1995R100RT was identified on the bottom line of the milled area as:  SBM98P1GARA.  Note that there is no sequencing number to that (well, it could be sequencing number & letters, as each position could be up to 26 letters) ....but, also note, that the same characters are located under the seat (top of rear fender) large stickers, relating to emissions & hose connections, etc.

For the milled area photo, below, the particular motorcycle was a R80RT. The driveshaft tag VIN and frame VIN agreed exactly, and the bike was a USA-shipped standard bike.  BTW supposedly had a transmission output shaft with groove and no circlip ...I was unable to confirm this positively.  If true, it may be the earliest bike to not have a circlip in the transmission that has been reported to me.  See my transmission article:

Repeating some information, per BMW factory bulletin 2298, if your State or Country requires an engine number, you are to use the top line on the milled-flat area below/forward of the left cylinder, on the engine case.

I have seen engines with that flat milled area being entirely blank!  These were not necessarily replacement engines! I do not have enough information to specify dates, etc.

More normally, the top line on that flat milled boss area below the left cylinder, see above photo, will have something like (yes, this is from an actual bike):  83 23 2175.   Note that these numbers are separated by two spaces, and the photo example above has one space.  Seems to mean nothing, except, perhaps, the factory had not 100% standardized yet??  83 23 2175  means that the engine is an 1983 model, produced in the 23rd week, and has a sequence code of 2175.  Do not count on that 23rd week as being when your bike was actually produced. Chances are pretty good your bike was assembled later. Also do not try to apply mathematics to the serial number range of total production you may find posted here and there for your year and model, you will probably get more confused, it probably will not correlate.  ESPECIALLY NOTICE that in my first example, BMW stamped the week number first, and reversed that in this, my second example!  BMW's own SI said week first!    I have seen many examples of this.  For sure, the bike was not produced in the 83rd week of 1923!  BMW eventually standardized on it's original service bulletin information, that is, it placed the week number first.

BMW, at some time unknown to me, made another change, and instead of spaces, they used forward slash lines.  My suspicion is that this was added security against re-stamping, but it may just be that a standardized stamping machine was the reason.  Example:  40/94/0030

The SI also says that the certification coding is the same for all engines is supposed to be ...meaning all R100 engines are one family code .......BUT! ...BMW did not follow this!  The SI is wrong.

BMW specifically said the second line (second level, lower line that is) is a requirement of the E.P.A. (Environmental Protection Agency), 'designated as required'.   I have been unable, so far, to find out what that designation really is.  Perhaps you would like to research the EPA rules and find out for me!  Maybe you can be the one who finally fully deciphers the second line!  I have only some ideas.  BMW stated:   "All  identification numbers on the motorcycle, i.e., numbers for each motorcycle produced are recorded in our data processing equipment in our Factory.  Therefore, it is possible to assist law enforcement agencies or the National Automobile Theft Bureau for theft inquiries only."  This SI was for U.S.A. and Canada, only.   It appears to me that BMW simply put the engine family number on the bottom line of the milled flat area, from ~~mid-1980's, and BMW recorded only the top line at the factory, for theft information. I may be wrong.

As noted, you may also find a VIN on a large metalized tag on top of the driveshaft housing...but note that in some rare instances it might not agree in one character ID (year identification could be off by one year). The production year, not necessarily same as calendar year, is identified by the 10th position in the VIN ...which I explain later in this article.   In general, the VIN on the metalized tag on the driveshaft housing will agree exactly with the VIN on the steering head or lower right frame.  You may or may not have the 17 character VIN number stamped (actually sort of cut-into with a dot matrix) into the metalized label, if found on the top of the swing arm tube.  You probably will find it, if there, on 1981-1984 motorcycles.  In a few instances, there may be a single letter or character difference. That is the year identification character, usually a letter. An example of an anomaly might be a late 1983-built bike. The very unofficial information ... is that BMW did not submit this end of 1983 calendar production early enough for California smog testing and some bikes were not quickly sold.  BMW cleverly added the metalized tag and put a letter in the VIN number on that driveshaft label so it passes the smog id requirements, yet the frame number that is "official" for registration, has a one year different letter.  In the example I am very familiar with, being a 1983 and not a 1984, the dipstick area does have the 7 digit serial number.  In every instance I personally know about, for this particular weirdness, the dipstick serial number is the same as on frame and tag.  The actual facts on this discrepancy are not known 100% for sure by me.  But, it does lend itself to folks possibly registering/titling a bike for either year.

BMW has had other anomalies in various models.  In some instances a bike might have been produced, as example, in July, which is way ahead of the yearly vacation time (after which, officially, the next calendar year models are produced); yet, that July-built motorcycle is officially identified by VIN as the next year's model.  This has happened now and then even into the 1990's.  I have no explanation that I can back-up factually.   BMW has done this with K bikes and Airheads.  I have information on a number of 1995 model year bikes (VIN has the letter S) that were produced long before the 1994 annual vacation (September return).   Rather a fair number of K bikes were built in the Spring-Summer of 1992, yet all are 1993 models (this is particularly so for the K1100, in which there are no actual 1992 models).   These findings also conflict with the idea that the date is of final assembly.

The actual month and year of production are supposedly easy to find out from the last 7 digits on these (or any) models.  In fact, the last 8 characters will identify any vehicle for date of 'manufacture' ...and often, as in our Airheads, one needs only the last 7 digits.  There are decoders for BMW serial numbers available on the Internet.  Some give much more information than others, such as adding the actual day of a month, and paint colors. Some websites for this are often not working at all.  BMW has never, to my knowledge, fully explained the dating system it uses, nor its various anomalies that have been found.  The only thing we really have is that motorcycles built after the Company-wide vacation in August, are 'normally' (my word) considered to be the 'following years model'.   We really do not know if the dating is the date it was completed on the production line, and before final checkout; or, date it went through final checkout; or, date it left the factory for shipment....and so on....and on. your head spinning already?  Take a break.  If overly confused, re-read this article from the beginning to this point.  Then come back tomorrow (suitably caffeinated, of course!).

Additional identification information:

For Airheads, you will find stamped transmission serial numbers or sequence numbers on the left side of the transmission case, just barely below the air-cleaner housing on 1984 and later; which you can see if you look just under the carburetor air outlet of the air cleaner box. Transmissions can also be identified by other information, such as the way the ribs on the bottom are cast, etc.  Identification of transmission years and other information is available:

If the flywheel is removed (Careful!  BE SURE to block the crankshaft at the front of the engine to keep the crankshaft from moving at all forward), the rear face of the engine casting is then exposed, and you can see casting information stamped (or cast-into) the area.  Typically there is a two digit number signifying the year of manufacture; and that number is surrounded by 1 to 12 raised dots.  These dots signify the production month of the casting.

Some engine blocks for replacement purposes were made without any serial number of the type normally seen on the pre-1984 models, that is, at the dipstick area. Further, later replacement blocks may have no number at the dipstick area, AND, some have no number(s) at the milled area below the left cylinder!   The dealer was supposed to stamp into the metal the old engine's number(s), and destroy the old engine and/or ship it to BMW.  Some dealers did not apparently have metal punches (being polite here) and thus there may be no serial numbers on those replacement engines.  I cannot usually tell you about the removal of dating on these castings with the flywheel (Clutch carrier from 1980 or 1981).

There were changes made to the oiling system passageways at the front bearing carrier, and engine blocks are coded for this change. BMW has an SI on this.  There is an article on this website with the two types of oiling systems sketches, and descriptions.   It is article 50B

Fully interpreting the 17 character VIN:

One of the many dealership bulletins said that for 1981 the number near the engine oil filler dipstick and at the steering head is not the official ID number. This is true, and always was true.  Any such number next to the oil dipstick was the serial number of the engine, and did not officially have to coincide with the frame number, but they almost always did.

I have BMW's own bulletins on many VIN things, and I have used them in this article, explaining discrepancies, anomalies, etc., as we proceed.  The basic 17 character VIN bulletin happens to correspond to what I know about all motor vehicles, having done vehicle registrations for two car dealerships (one also sold boats and motorcycles, etc) for a few years.   Unfortunately for you, BMW's bulletins need some interpretation, as BMW had their own anomalies (most of which have already been discussed prior to this paragraph), and BMW did not explain things all that well in some areas (THAT is not unusual!).

You could, if interested enough, find a copy of FMVSS, perhaps on-line, and read to your heart's content.

One of BMW's bulletins that we are concerned with is entitled ..."Decipherment of BMW VIN's According to FMVSS 115".   The bulletin seems clear enough, except for one particular thing! ....There is an asterisk and short line printed at the bottom of the bulletin. This is how that line reads:
*  Motorcycles produced before April 1/1981 have the letter "M".

The bulletin does not show another asterisk to show what part of the VIN that the above asterisk applies to!   It might even mean "just for the 1980 year for WBM beginning the VIN"....and that is what I believe  ....keep reading, and you will see an example of why I believe that.

During the 1980-1981 period, as the 17 character VIN was being introduced, BMW manufactured some motorcycles with anomalies in the VIN.  Here is an example with spaces added by me for clarity:
WBM 0 43503 A 6175002.
This motorcycle was actually built in September of 1980.  NOTE the M character in the VIN.  That M apparently stands for motorcycle. After April of 1981, BMW dropped the M, and in place of the M, BMW began using a digit,1, to indicate a motorcycle.  The 0 indicates a two-wheel vehicle, and that, and the rest, conforms to the standards shown below on how things should be officially.  Astute observers (are you one?) will note the Annual Vacation period for BMW and the date of September 1980.  Extra Astute? realize the factory workers were back, producing 1981 model year motorcycles, in September 1980. Think through what was in this paragraph!

The BMW dating methods for calendar and/or specific production or declared year motorcycles has created problems at times with various Departments of Motor Vehicles.   It would be nice for them to all understand that BMW's model year motorcycles could have been ""produced"" in Sept-Oct-Nov-Dec of the prior year. Of course, now, YOU can answer (or question) what Produced and Year really means, with the BMW anomalies!  There are some very specific anomalies I have not yet mentioned (isn't all this fun?).   I will get into the strange stuff later herein.

Here is how things should be, without any anomalies.  Nothing particularly special about these two motorcycles, nor year nor model, I just grabbed this information as it was available and easy to use.  Note that the fact that there are always 17 characters, and always a very specific place in the VIN for each character and always for its meaning, ....and, the entire 17 character VIN system is in use by the USA (and other countries too), with specific laws/regulations/acceptance, of this internationally accepted system.

For an R65:
WB10 364 0 4 B 6 385 003 
{the actual VIN would not have spaces}

Here was my own 1983 R100RT:
WB10 449 0 9 D 6 243 160
{the actual VIN would not have spaces}

Now, let us take a look at the above VIN codes in order, starting from the left side:

W means that the manufacturer was in Europe.   Combined with the B, it means BMW-AG, Munich, West Germany.

1 means motorcycle. I already discussed earlier models in which that 1 might be a M.
0 means a two wheel motorcycle. you think your Harley was shipped by the factory as a trike or sidecar unit ....look! ...

BMW may, in parts lists and other places, show a 'model code' as 364 (that is for a certain type of R65) and 449 (that is for a certain type of  R100RT).  They might have a zero in front of that number.  Confused about just that maybe zero?   Keep reading ...all will be explained.

Going onwards with the decoding, after the 0 meaning a two wheel motorcycle:
The 3...or the 4 shown for the two bikes above, identifies the LINE TYPE.   In the case of the R65, the line type for a 3 is 248/1. In the case of the R100RT, the line type for a 4 is 449 ??...naw, it is 247.  Confused?  Basically, you can almost ...but not quite ...forget these.   For the nerdy, the R45/R65 bikes have some different numbers, and all the big bore bikes could have the same ..but other ...number.  Are you confused more?

Perhaps you are a Member of the Airheads Beemer Club that states in its purposes, Club Membership is for the 247 type ...are you confused?   That's because of how the club bylaws were original stated. The R65 was a new model, a short stroke model, and it did not get sold until the 1978 model year.  Airheads Beemer Club does include both the 247 and the 248, but that is unsaid in its club purposes statement, because the 248 motorcycles did not exist when the Club was founded.

Here is how to think (if you want to!) about the LINE TYPE:  You won't be using it very often, and when you do, it might be with ME, Snowbum, or maybe some other "guru", when you ask about such as a specific bike electrical wiring diagram.  BMW factory literature for wiring (which I have for nearly every Airhead, foreign and USA), uses LINE TYPE modifications to identify specific versions of a model.    Thus, if asking me for a schematic diagram for your bike (assuming it is not already in this website), you would need to give me the model number of your motorcycle (such as R100T, R100RT, R65, R80, etc...), and the LINE TYPE NUMBER, if you can find it.  I can determine it from the serial number or last seven characters of the VIN, if you do not know it.  You may find it under the seat or on the top of the rear fender, etc.

Continuing ...with decoding the 17 character VIN:

6 (for the R65 here under discussion) identifies the engine type, that is, number of cylinders, whether gasoline or diesel, and the size of the engine, and if 2 or 4 stroke. It is a BMW in-house coding.

The next digit, for the R65, a 4, is the NET horsepower.  In this instance, the 4 stands for 45 BHP.  Astute observers may notice that in the R100RT the claimed horsepower by this coding is 90 or more.  yeah, sure.... riiiight!

The following 0 had no meaning, that is, it was there and had no special meaning on my version of the BMW SI.

A bit nerdy:  Next comes the 9th character, a check digit, the 4 in the case of the R65, the 9 in the case of the R100RT. Check digits have many uses, primarily it is a digit to tell a computer if things are possibly wrong in the rest of the sequence of characters.  If you are nerdy enough to want to know how to interpret check digits ...or how they are determined, see the following, and I suggest you read all three if you are really, truly, interested:
That last link contains some quite interesting details, and explains, to some degree, why the ID numbers can sometimes be confusing in some countries and some years.

NERDIER:  Here, I greatly simplify the check digit, although the above articles have a lot more information.  The check digit is a mathematically calculated value, calculated from the VIN position, an assigned code value, weight, and other things.  Whatever results they get from that, they divide by 11.  That becomes the check digit.  If the result turns out to be a 10, then the check digit is a character:  X
Don't you feel clever now? (more likely, you are cussing Snowbum for his habit of excessive details)

Officially, according to the adopted International Standards for official VIN 17 character numbers, the 11th position, in the examples, this is a "6", is to identify the assembly plant.   Note, however, that this was supposedly identified by the WB, as explained much earlier.  Well, yes, but it is possible to have differences and more details, multiple plants, maybe in same area; .....meanwhile, forget it!

The 10th position is the letter identifying the year and it is the production year or the assigned year (whatever either of those means), which you understand is not necessarily and certainly not always the calendar year.  Notice the B in 10th position for the R65 example and D in 10th position for the R100RT example.  That letter is the year code. This system is for U.S. production.   I will get into this in depth after the horizontal line, below. The Wikipedia article, link three paragraphs up, contains several charts of some interest, and I don't include hardly all the information here, and below!

For the second time that I've said this, I suggest you re-read this article up to this point, then take a nice long break, then come back and finish reading the article.  I also suggest that you check your own, and other's motorcycles, cars, etc., and try to use your knowledge (refer to this article) to determine what those vehicle VIN's mean, character by character.    Then, read the rest of this article again. I promise, it is all going to get a lot clearer!

I leave you at this point where you should be taking a break....but, will mess with your head with one last thing before you take a break:  the 11th position, which BMW uses as the first digit of the 7 digit serial, is used by most manufacturer's for the manufacturing plant code.  This can get a bit complicated, and with BMW, can add to the id confusion, so I won't get into it here.

In depth:

Information first on the production and model year of any motor vehicle, & identification, from the above mentioned 10th character (reading from the left, of course).

BMW has an annual vacation period, the month of August.  Vehicles produced after August are normally identified with the following calendar year, for official identification.    In some instances, BMW has used the actual manufacturing date for the VIN year identification. This is seen in the late 1980 to April 1981 production, where A may have been used.  As noted earlier, the VIN starts with WBM on those particular bikes.

There have been various anomalies; and, I've already mentioned some in this article, but there are many more; and, this is the only major one I know of:  The K1100LT was produced as early as April of 1992; but all produced in 1992 were officially 1993 models.

Here's a minor anomaly:  I have personally seen a photo of this ID plate.  It was a R1200GS, produced in January 2004, but the VIN identifies it as a 2005 model, but the factory pages identify it as a 2004.

So, there can be unusual or non-standard things seen; but, the vast majority of motorcycles will be standardized.  Lots of weirdness during the 1980-1982 era.

Character codes to identify the Official Year:
Official Year may not be the year of actual manufacture, because the next Official Year of production begins the first of September, after the company month-long vacation of August:

Below is what you should expect when decoding the year character of the VIN (10th character reading from the left):
1980 vehicles used A
1981 vehicles used B
1982 vehicles used C
1983 vehicles used D
1984 vehicles used E
1985 vehicles used F
1986 vehicles used G
1987 vehicles used H
Letter I is not used
1988 vehicles used J
1989 vehicles used K
1990 vehicles used L
1991 vehicles used M
1992 vehicles used N
Letter O is not used
1993 vehicles used P
Letter Q is not used
1994 vehicles used R
1995 vehicles used S
1996 vehicles used T
Letter U is not used.
1997 vehicles used V
1998 vehicles used W
1999 vehicles used X
2000 vehicles used Y
Letter Z is not used

2001 to 2009 vehicles use digits 1-9:
2001 vehicles used 1
2002 vehicles used 2
2003 vehicles used 3
2004 vehicles used 4
2005 vehicles used 5
2006 vehicles used 6
2007 vehicles used 7
2008 vehicles used 8
2009 vehicles used 9
Numeral 0 is not used in the years position

After 2009 the letters of the alphabet were used again:
2010 vehicles used A
2011 vehicles used B
2012 vehicles used C
2013 vehicles used D
2014 vehicles used E
2015 vehicles used F
2016 vehicles used G
2017 vehicles used H

Letters I, O, and Q are not used.

Letters U, Z, and the numeral 0 are not used in the years position of the VIN.

If you want to be truly nerdy, read the rules/regulations on VIN numbers:

For a quick way of determining, on many models and especially later years, the manufacturing model year and month+ (I have seen this return errors once in awhile):
When using that, you may see ECE shown, this means the bike is for World Markets.  Unfortunately, that can require 'more interpretation' at times, so I am not getting into it here.

Here is another website URL, which you may prefer, which uses a different chart format for serial and full VIN's:, was working the last time I tried it. 

An excellent link which included original color, etc., was at,  but it was not working recently.

I have other websites I use, some from Germany, and a factory site as well.  Some require private codes for access.   For whatever reasons, often most of the links don't last long.

A source for information, for the early bikes, but direct to BMW:
Send an email, with your motorcycle's serial number and request information that they have, to

****The format for day, month, year, is not the same for all countries.  In the USA, it is common for the month to be listed first.   If you see a discrepancy between VIN decoders, do consider this!

How to go about identifying your AIRHEAD BMW frame, engine, driveshaft, transmission, etc.
Note that a BMW Airhead motorcycle is often modified.   Many parts from many years will interchange physically; or, otherwise can be substituted or exchanged, modified, etc.   I have also seen many factory anomalies.  The more information, the better.

1.  Does the engine have a serial number stamped into the area that the oil dipstick screws into?    What is that number?    It can help determine MANY things besides just the transition between 1983-1984.  It can also help if the block was a replacement type, by its presence ...or not.

Below & forward of the left cylinder may be a machined flat boss.   Yes?   No?   If there, it will have various characters stamped into it.   Exactly how is this stamped, ....both top line and lower line?

2.  If the flywheel is removed (read this article first:, the rear face of the engine is exposed, upon which you may see casting information stamped (cast-into) the area.  Typically there is a 2 digit number signifying the year of manufacture; and that number is surrounded by 1 to 12 raised dots which signify the production month of the casting.  What is that information?

3.  Does the bike have a rectangular airbox?   If the answer is YES, then squat down and look JUST UNDER the LEFT carburetor air tube coming out of the rectangular airbox.  There may be a stamped number, possibly prefixed by one or two alphabetical  letters.  If so, what is it?    That can help identify the transmission.  The number being stamped there started with 1984 models.   Is the rectangular airbox itself peculiar?   Do you have the PulseAir system?  Are the cylinder heads seen to have, just below the exhaust port, .....plugs or other evidence of the motorcycle having come with the Pulse Air system, including ports at the rectangular air cleaner housing? Does the rectangular airbox have tapered snorkels?    Are the snorkels identical in length, etc? Are there small holes in the inlet bell area of the snorkel(s)?

4.  Is there an electrically operated fuel shutoff solenoid (and same for fumes from the gas tank to the crankcase) both located in the starter motor compartment on the inside of the cover?   If not, does the starter area engine cover have extra holes for such items and their plumbing?

5.  With removal of the starter area cover:  is there, on the left side of the starter, sticking straight up from the engine, a short small round pipe?

6.  The right side lower frame tube may have a stamped 17 character VIN number in it.  That stamping is usually located on the frame tube directly below the right carburetor. It is on the frame at the rear motor mount.  Show what that stamping is, whether 17 characters (or otherwise).  Located there, a 17 character VIN will identify the frame, and likely the entire bike (the 7 digit serial portion can, from FACTORY information, identify equipment, special colors details, ETC).  Some foreign-shipped bikes had a serial number, not a 17 character VIN number, and the serial may be 'strange' could have letters in front, or, nearly anything associated with numbers and letters.  Some motorcycles may have a riveted or glued-on label, in addition, or even covering the VIN.  If anything, list the details.

7.  You may have a large silver label on top of the driveshaft tube.  If so, it will probably have the 17 character VIN number, punched-pricked into the label, and difficult to read.  What are the characters?

It is possible, although rare, for various VIN 17 characters to disagree slightly, but should not for the last 7 digits.  Discrepancies are usually one letter in the date position of the VIN.  If there are any discrepancies, describe, in detail.

8.  Does the bike have snowflake wheels?      Describe whatever wheels you have.   What is the front rim size? In diameter and width as stamped?   Same for rear rim size?  Yes?  No?   Details?  You may want to read this article about the front 19" snowflake wheels:

9.  What are the characters stamped onto the nose of the rear drive, that is, the top front area.

10.  What are the very small numbers printed on the lowest area of the face of the speedometer, it may be something like W=1.112.
What is the color of the numerals on the speedometer?  Color of pointer?   Peculiarities such as a white surrounding line?
Are the larger physical-sized speed numbers for Kmh or Mph?  If you have a 1974 or later, the instrumentation is in one 'pod' the neutral lamp identified by the word neutral, or by a zero?
What is the maximum speed value as printed?
Does the tachometer have the same color scheme as the speedometer?

11.  Is the rear drive a Monolever or a Paralever or a Twin Shock?

12.  Does the driveshaft housing have an ~2-inch welded-in section at its rear flange area?

13.  Describe the transmission cast webbing on the bottom, including if both directions, or? 
Describe any characters stamped into the left side of the transmission casting, such characters would be located just about meeting the top transmission surface.
Describe, if the transmission is removed, any logos, numerals, characters, etc, found on the front (or?), and note exactly where they are found.

14.  Does the bike have a BMW FACTORY fairing or flyscreen?  RS style? RT style?   S style?  or?  Describe fully, including type, color, etc.

15.  What is the color of the motorcycle tank, fenders, etc.?  If you have the factory color code numbers, which may be under the seat or on the top of the rear fender, what is that color scheme code?

16.  If there is a tag with three or four digits on it located under the seat (typically on top of the rear fender), what is printed on it?

17.  Does the title or registration call out Type "RS".  I do not mean Model.   The "RS" for TYPE does not mean BMW RS model).

18.  Anything you can think of that might help determine what this bike really is?  This can be most anything, even including the make/style of front brake(s) if a disc brake; one or two front discs. Has rear disc?   Anything strange about the bike you have not yet noted? ...this can include anything about the carburetors (model number is stamped onto them), exhaust system, instruments; alternator, wheels, etc!   If there is anything you notice, describe it as best you can.

If you are requesting information on a specific bike, for a specific purpose (please do not over do these requests), you may want to copy the sections 1 through 18, above, and send them to me...or, better yet, to the Airheads List...include the specific request and reason.

02/13/2006:  Minor updates, and changed the URL.
11/27/2007:  Change to 67A from 67
01/10/2009:  Update with information to cover all vehicles; extend years/chart information; clarify a number of items.  Incorporate finer details.  There were NO errors previously.
04/19/2011:  Add information (from my MODELS article) on engine casting numbers as seen near the crankshaft output; and on replacement blocks.
06/11/2011:  Clean up article.  Then mess it up by incorporating every anomaly I know about, then clean it a bit more.  All done at various times today.  Final release was 1015 hours Pcst.
06/11/2011:  Another small change. 
08/26/2011:  Add section Addendum #1
03/26/2012:  Go through article completely and clarify some confusing items.
09/18/2012:  Clean up article.  Clear up an ambiguity.  Add QR code; change Google coding
09/19/2012:  Edit to show what BMW meant by the M in 1980-1981 period; give example; and, further information, several place in this article.
10/17/2012:  Update for anomaly for a 2004/5 R1200GS
11/29/2012:  Clean up
12/21/2012:  Add URL for .de archives
11/19/2013:  Add reference note regarding pre-Airhead bikes
06/24/2014:  Minor updating on years and anomalies; more of same on 07/02/2014.
01/08/2015:  Minor updating.
10/03/2015:  Major revision for clarity
07/17/2016:  Update metacode & some <br /> tags to <br>, scripts, fonts, layout.  Shorten article somewhat regarding some redundancies.  Clarify interpretation of milled flat area coding, etc. 
05/07/2017:  Add two more hyperlinks, particularly covering years', codings', and the various ID systems in use around the world, which not only are different, but may be different depending on the number of vehicles produced & shipped.
09/22/2017:  Minimize fonts & colors. Clean up html. Clarify some details.
01/18/2018:  Clarify some details. Clean up the article more.
10/26/2018:  Split 1 into 1A and 1B, adding 1B text (from early in the article).  Correct minor typo in paragraph about "M".
04/03/2019:  Improve explanation for ECE models.
12/20/2019:  Completely go through entire article, cleaning up code, grammar, spelling, & clarifying information. 
12/21/2019:  Add a sentence about the first digit of the 7 digit serial.
01/11/2020:  Cleanup, add hyperlink, etc.
10/25/2020:  Revise entire article for additional clarity, but were NO substantial information changes.

Copyright 2020, R. Fleischer

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Last check/edit: Saturday, December 17, 2022