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Crankshaft end play, spacers, ETC:

Fairly rarely; and, after huge mileage.. usually (but NOT always).. one sees an Airhead that has two or more of the following symptoms: Shifts hard (and isn't lack of input shaft lubricant or bad clutch); most probably has a lurching, grabby clutch action; idle rpm is unstable and varies with clutch pull-in; engine vibration. If you have an airhead with those symptoms, you may want to check the end-float (end play) of the crankshaft. This is a serious subject. You are advised to see an expert, or to get the BMW official information, but here are some things that may clear things up a bit. This is the arrangement you might typically expect to see if you removed the crankshaft and viewing the crankshaft in the engine casting from the crankshaft rear end:

FIRST you have a GREEN thrust spacer which is .1015-.1034 in thickness; next is the main bearing insert, next is the RED thrust spacer which is .0978-.0996, then the oil seal, then the flywheel. This is for a 1970-1978. In 1979 BMW added the O-ring seal and the flywheel changed design a bit. If you have a BLUE thrust spacer it is .0996-.1015" thick; and a YELLOW is .1034-.1052. The limit of wear is .008" and end float is .003"-.006".

What are some simple tests you can do to determine if your transmission has a problem developing?
    (1) AFTER a 10+ mile ride to THOROUGHLY warm up the engine and transmission,  jack
         or otherwise block the rear wheel so it is slightly off the ground. With engine off, in neutral, spin
         the rear wheel by hand as fast as you can and listen to the gearbox. This spins the output shaft
         bearings only.   The transmission should not be make bearing noises when the rear wheel is
         spinning.
    (2) Start the engine (this is with hot engine and transmission) and let it idle in neutral. Pull the
           clutch in for a few seconds and then let it out.   When the clutch then engages, this spins the input
           shaft and cluster shaft bearings only. There should not be a bunch of bearing noise when you
           let the clutch out (you may hear some normal clutch spline chatter).
    (3) With the engine off and the transmission in neutral, rotate the rear wheel forward SLOWLY. This is best
           done with the transmission hot from riding. If the slightest notchiness is felt, unbolt the driveshaft from the
           output flange of the transmission and rotate that flange with fingers. ANY notchiness is cause for the
           transmission to be overhauled. NOTE that the transmission output flange has 4 special bolts, and they are
           NOT to be used with any type of lockwasher, contrary to what you may be told. The thread length
           of the latest PROPER bolts are slightly shorter, as the old split lockwasher and longer bolts should be
           eliminated.
           There is information on this website about that: Drvshtboltstoolstorque I suggest you read that
            article.   The threads should be cleaned, and then a bit of Loctite BLUE applied, and tighten to 29 foot
            pounds. There are various methods of enabling use of a torque wrench here. You can just give the bolts a
           good grunt with a 12 point wrench; or, torque them properly.
            See ALSO my TOOLS article on this website.

    (4) Inspect the transmission drain plug, which has a magnetic center.   If the transmission is quite
            COLD when this is done, and you are quick about it or have three hands and extra fingers to
            plug the hole, you can loose hardly a tablespoon of oil (otherwise, drain and collect it).
            Inspect the drain plug. A modest amount of FUZZ, soft-feeling, is fine. ANY feelable sharp
            particles are cause for further inspection. NOTE that fairly large amounts of FUZZ, soft-feeling,
            after maybe only a few thousand miles since an oil change (and fuzz removal), CAN indicate
            that the transmission is failing....and for the circlip-less versions, indicate that the 5th gear bearing is
           deteriorating, and the transmission really should be overhauled and the circlip installed.

     (5)   This test needs to be done PARTICULARLY on transmissions that fall within the No Circlip guidelines,
            see below. Disconnect the driveshaft from the transmission output flange, and hand-rotate the output flange.
            Transmission should be in neutral, and preferably still warm from a ride. ANY roughness or irregularities
             noted in the rotation is cause for transmission teardown and repair.

These tests, except #5, are not necessarily 100% conclusive, and later in this article are some other tests, so do NOT stop reading HERE!

What are some common things that are not usually a transmission failing problem?
(1) Small amounts of 'fuzz' on the magnetic drain plug, perhaps seen at every 20K-30K gear oil change. The fuzz will NOT
        have sharp particles.
(2) Rattling noise from gearbox in neutral after thorough warm-up.
(3) Shifting problems, especially from 2nd gear downward:    clutch/input splines need lubrication (unplated early shafts tend to
            need cleaning and lubrication at 15,000 mile intervals, nickel plated shafts at maybe 25K).
(4) Shifts not always made.   Check the screw in the shift arm...they are known to loosen. Use Loctite BLUE.

The "circlip":
The Circlip problem applies to ONLY some 5 speed transmissions!:

OVERVIEW of the circlip problem:
From sometime towards the end of the 1984 production year, or beginning of the 1985 production year, BMW's transmission maker made a modification to the transmission. On the output shaft, they left out a snap ring (circlip) and the associated output shaft groove...located at the nose end. The part number for the shaft was not changed. That modification can and did give a lot of grief to owners. About a decade later the design reverted back to the original reliable version. A number of these 'circlipless' transmissions have failed, some have had catastrophic failures, ripping the transmission to pieces.

Here is a link to Anton's website, with photos, and some text, on the circlipless transmission problems...you may find it enlightening!
http://www.largiader.com/articles/circlip/

There is not 100% agreement, only maybe 95%, on the exact mode or reason for the relatively common failure of later circlipless transmissions. There are two widely differing basic opinions. Information here comes from a variety of sources. In particular, information and food for thought, in real detail, first appeared in a 2001 Airheads LIST posting by Bob Clement of BMW-Montana, who gave me permission at that time to post his correspondence with me, which I did the majority of, on the LIST. In the article you are reading I have added further comments from private communications from several experts in this area, and also my own input. Thus, what follows is a mixture of information from several sources. This article in its original initial form, was been submitted and commented upon, and generally approved, by transmission experts. This article, well, the circlipless information, has since been updated by ME, and has not been re-submitted. It is believed 100% accurate, however.

Many private owners have overhauled their own transmissions, some seemingly quite successfully, some using information, tools and parts from Ed Korn. Most owners will not want to overhaul a transmission themselves, and will entrust it to an expert, as their are some real tricks to making a transmission last and have smooth operation. Four of the better known overhaulers are Tom Cutter; Orlando Okleshen, better known as OAK; Motorwerks; BMWMontana; Matt Parkhouse; and Bruno's in Canada (I think, no personal experience with them). Some names and other information are at the close of this article...and I make recommendations. I am willing to offer my personal opinion on these people, via telephone. I have some reservations about some of them, in their workmanship.

Determining if you have one of the possibly troublesome no-circlip transmissions:
This is not so easy, not so cut and dried. A factory bulletin in 1986 gave no specifics on year and transmission serial number. There was no change in part number for the output shaft. THAT is not unusual for BMW, BMW is known to sometimes make a production part change and to use the same part number. It APPEARS that the transmissions that were affected were shipped with motorcycles of build date beginning near the end of 1984, so that means that as early as some 1984 models may not have the circlip. But, as I write this, I have had reported to me NO 1984 circlipless transmissions. Airhead production ceased for the public in 1995. There was another, later, factory bulletin, #280, dated 12/08/97, explaining that the circlip (and, therefore the groove) was reinstated, and the SHAFT number was CHANGED. HOWEVER, it appears that the shaft is actually the same as the 5 speed output shafts built from 1974 into 1984. The specified 'new' shaft is 23-21-1-338-793. BMW raised the price of this shaft tremendously. One can, and competent transmission overhaulers DO, modify the non-circlip shaft, but this needs to be done very carefully. The bulletin also mentioned a 'special bearing' for the front of the output shaft. There is some controversy about this, and this bearing was made by a Japanese bearing manufacturer. More later herein.

Transmissions beginning with serial 240765 had the circlip re-installed. Confusingly, no year was specified, but it appears to be mid or late 1995. Further confusion exists... as year of production and transmission serial number may well not go hand in hand. I have obtained information on model year versus transmission serial numbers, and they are presented later in this article.

Summing up: ....theoretically it is possible for a transmission built from the end of 1984, up until transmission serial number 240765, to not have the circlip (and the shaft has no groove for it).

How do you find your transmission serial number, and what range of serials can you expect?? Transmission serial numbers are found in one of three places. Early transmissions, from 1974 to 1981 (or, I believe, as late as 1983, depending on country the motorcycle was shipped to), will have the serial number centered on the top rear center or top front center, where you can not see it without removing the air cleaner, etc. Thereafter, the serial number is located at the top area of the left side, just barely below where the left airbox outlet hose connects; so you have to squat down to see it. Serials are stamped into the aluminum transmission case. There are some variances, and so noted below.

When reading in this article about 'year', be advised that BMW's 'model year' includes motorcycles that were built towards the end of the prior year, and it is quite possible to see, for instance, a build date of September, to be included in the following year's model. This is due to BMW policy of closing the plants for the annual holiday (vacation).

1974:   serial numbers ranged from Y-4300 -> Y20050; after which the numbers continued withOUT the Y letter.
1975:   information sketchy, some end of 1974 transmissions probably used, may have Y prefixes; otherwise no Y.
            numbers from 4225 -> 13500 have been identified.
1976:   No letter. Probably uses serial numbers 25000 through 51000, some of these may be in 1977 models.
1977:   Some from 1976 used, so one can expect serial numbers from 46000 to 63000
1978:   72400 -> 83000, and THEN had a prefix letter Z.   Some early 1979 transmissions may be that way too.
            Z-0870 -> Z-0940. Serials are now on the FRONT inside face of the casting.
1979:   All have Z number, from Z-19100 -> Z-36750 at least.
1980:   The Z number now begins with a zero: Z-052800 -> Z-064950

From 1980, for awhile at least, to 1982, things now get a bit confused, with serial numbers going to much earlier serials, with a later year.
1981:   There are some numbers that seem to fall in the 1980 group, but the casting is different. Most will find that the
             serial number is now on the left exterior side, as I noted it to be, just below the left hose of the air cleaner. Expect
            serial numbers of Z-006111 -> Z-029900
1982:   Z-03660 -> Z-060400
1983:   Z-074700 -> Z-084299
1984:   Z-084339 -> Z-104600
1985:   Z-113701 -> Z-130150
1986:   ZSA-125500 -> Z-125600
Note:   BMW seems to be using, at least a fair amount of time, the letters ZSA for kickstart transmissions.   More information will be provided to clarify this, in the future.

1987:
1988:   Z letter is dropped.   From 1988, serial numbers all now have a 3 letter suffix.
            expect numbers from 0147440 AAB -> 0164300AAI.   Suffix's may, however, be AAB, AAI, AAJ, ETC.
1989:   0154140 -> 0176330 and suffix
1990:   0180939 and suffix
1991:   0190460 -> 0198650, and suffix
1992:   0207050 -> 0215650, and suffix
1993:   0204190 -> 0230075, and suffix
1994:   0237930 -> 0238660, and suffix
1995:   0236539 -> 0254340, and suffix.   Some 1995, probably early ones, had NO circlip

I am collecting information on bikes with KNOWN circlip-less transmissions....THAT MEANS...known BY DISASSEMBLY. Reported to ME circlipless transmissions are:

1986 R65, transmission Z123469, VIN........................6128105, production 9/1985
1986 R80, transmission Z125576, VIN WB1046303G6480655, production 10/1985
1986 R80GS, transmission # unknown, VIN WB1034801G6363284, production 10/1985
1986 R80, transmission Z128362, VIN WB104630XG6480782, production 12/1985

1987 R80RT, transmission Z138188, VIN WB1046407H6491304, production 10/1986
1987 R80 USA, transmission 0144961AAB, VIN WB1046304H6481119, production 05/1987
1987 R80, transmission 0138910AAB, VIN WB1046301H6481093, production 11/1986

1988 R100GS, transmission 0151096AAI, VIN WB104780XJ6152090, production 11/1987
1988 R100GS, transmission 0155023AAI, VIN WB104780XJ6152610, production 02/1988
1988 R100GS, transmission 0156870AAI, VIN WB1047803J6152688, production 03/1988
1988 R80 monolever, transmission 0161951AAB, bike serial number 6448037, production 09/1988
1988 R100RS, USA model, transmission 0154894AAB, VIN WB1046600J6247481, production 02/1988

1989 R100GS, transmission 0163629AAI, VIN WB1047809K6153197, production 10/1988
1989 R100PD, transmission 0171806AA1, VIN WB1047905L6134016, production 06/1989

1990 R100RT, transmission 0180939AAB, VIN WB1046902L6293473, production 04/1990

1991 R100RT, transmission 0185431AAB, VIN WB1046908M6293561, production 08/1990
1991 R100GS, transmission 01292165AA1, VIN WB1048803M0230223, production 02/1991

1992 R100R, transmission 0204181AAI, VIN WB1048706N0280049, production 10/1991
1992 R100GS/PD, transmission 0209970AA1, VIN WB1048909N0047487, production 01/1992

1993 R100GS, transmission 022756AA1, VIN WB1048801P0231259, production 09/1992
1993 R100GS, transmission 0226691AA1, VIN WB1048304P6467330, production 12/1992
1993 R100GS, transmission 0228652 AAJ, VIN .....646450, production 01/1993

1994 R100R, transmission 023696AA1, VIN WB1048709R0280858, production 01/1994
1994 R100R, transmission 238655AA1
1994 R100GS, transmission 0237931AA1, lug stamped NI
1994 R100GS, transmission 0238984AA1, VIN WB1048805R0231610, production 01/1994

MORE TESTING:
There are some fairly simple tests that an owner can do to see if the transmission is likely OK. These tests are not 100% positive for identification, but are usefully OK....for the problem in this article....or other problems. PLEASE re-read the section at the very beginning of this article on simple testing...especially #5.

(One): examine the drain plug, which has a magnetic center. Only a modest amount, perhaps at worst dime sized soft oily fuzz, is OK; there must be NO hard feelable particles. This is a test that should be performed on ANY airhead transmission at any normal oil drain/change interval, and probably is a very good idea to be done more often, if you have a 1984+ motorcycle. It is quite possible to check this drain plug without losing hardly any oil, if the test is done with the filler plug IN PLACE, and when the oil is cold, and a cork...or finger...used to plug the hole during inspection.
Repeated from above: A modest amount of FUZZ, soft-feeling, is fine. ANY feelable sharp particles are cause for further inspection. NOTE that fairly large amounts of FUZZ, soft-feeling, after maybe only a few thousand miles since an oil change (and fuzz removal), CAN indicate that the transmission is failing....and for the circlip-less versions, indicate that the 5th gear bearing is deteriorating, and the transmission should be overhauled and the circlip installed.

(Two): Have the rear wheel slightly off the ground, transmission in neutral, and rotate the rear wheel slowly. No notchiness should be felt. This test can be done with the transmission cold, but is a bit more revealing if done just after a 10 mile+ ride, so the oil is hot. This test tends to also show up a bad bearing caused by allowing water to get into the transmission, usually from over-vigorous spraying during washing (at the hollow speedometer cable bolt), or from a bad speedometer cable rubber boot (very common problem, both water problems can lead to $$$ repairs). This test also tends to show up bad driveshaft u-joints on the Paralever models, and disconnecting the U-joint at the transmission output flange, and rotating that flange, will allow a yes or no on U-joint and transmission. NOTE!....I highly recommend making sure that your speedometer cable boot fits snugly, and is either internally stuffed with grease, or sealed at the top with silicone RTV; if the top is poor, water can run down into the transmission, causing $$$ damage. Milky (coffee with cream) look to transmission oil is VERY BAD to have happen...it destroys bearings.

For the problem under discussion, the circlip-less transmissions, the most important indication of a SERIOUS problem that you may have is sudden VIBRATION....and possibly noises. If you feel an unusual vibration, and it need NOT be suddenly extreme at all, not even very strong at all, and determine that it is transmission related (pull in the clutch at a stop, engine running....try in gear and also in neutral), that is the time to stop, right then, and have the bike towed. Failure to comply will likely, within a few miles, lead to a massive failure. I CANNOT EMPHASIZE THIS ENOUGH, FAILURE TO STOP RIDING, NOW....NOT 50 MILES LATER AT THE NEAREST DEALERSHIP OR REPAIR SHOP,,,, CAN COST YOU A BUNCH MORE MONEY.

In fact, if your transmission is in the range of the circlip-less ones, you might SERIOUSLY consider an overhaul well before you have a failure, as the number of $$ parts to be replaced always greatly increases as you let the transmission accumulate mileage.

What to do?: Even if you hear and feel nothing peculiar; every few thousand miles, put the bike on the centerstand, when the engine and transmission are thoroughly warmed up. With engine off, spin the rear wheel and listen for growly sounds. Turn the wheel slowly and feel for notchiness. When the engine and transmission have cooled overnight, check the drain plug. GENERALLY the degradation is slow, but sometimes it DOES come on suddenly....noises and/or vibration. Do the #5 test!!!

NOTE: BMW, like most manufacturing companies, is tight-lipped regarding engineering details when it makes a change. BMW tends to be more tight-lipped than many companies, probably from both a corporate policy and the Germanic 'we don't wrongly engineer ANYthing, WE don't have problems....'. BMW, Germany, or North America, may well issue Service Bulletins of various sorts, now and then, but these often do NOT spell out details that one might like to have, and sometimes are confusing, especially by what is not said. We have to live with that. Sometimes some of us Wenches manage to get information that is not very public, to say the least. In in some instances I have been given information that is almost to be considered Top Secret. I can NOT divulge in such circumstances my sources, and can almost never exactly quote the information. BUT!!.....one way or the other, in almost every instance, I DO manage to get the information needed to you all.

#1: This is the more commonly accepted viewpoint:
It is this viewpoint that I tend to agree with.
There are three shafts in the transmission, INPUT, INTERMEDIATE, and OUTPUT. The front gear teeth on the output shaft is manufactured on an angle, that is, the gear is HELICAL cut. Its mate must also be on that same angle, aligned to mesh. If you picture in your mind such a gear on a shaft, and another shaft with a mating gear, and if power is fed to ONE, then the other is being forced to move along the axis of the shaft, not just being rotated. This direction of axial force reverses, depending on powering from the engine, or engine braking. In the 5 speed transmission, even in neutral, the forward gear (5th) gear on the output shaft is being pushed forward any time the clutch is engaged, even in neutral, except in the coasting condition. A BOSS on the front of that gear pushes against the rear face of the inside race of the front output shaft bearing. That rear face of the inside race of the front output shaft bearing is the thrust surface for 5th gear. Thus, 5th gear is constantly trying to push against the front bearing. There is a tiny amount of end to end float in the shafts fitment in the transmission case (a few thousandths of an inch), established during the shimming process, which ensures that the bearings are not subjected to end-preloading. Ball bearings, used in this transmission at that point, do NOT like preloading, that makes them heat up, and fail.

There ARE some very special types of ball bearings designed for end loading, these are used in such as the worm drive shaft on electric winches, but this is not pertinent here (and those bearings are VERY pricey).

Prior to the change in 1984 ??, there was a hardened snap ring that fit in a machined groove on that output shaft, it was just forward of the gear, and prevented the bearing from moving forward by that mentioned angle cut gear pressure. That kept the pressure from eliminating any decrease in the shimmed float.

When the clip is left out, usually what happens is that the large front bearing overheats first, and begins to self-destruct, and the cage which keeps the balls in place starts coming apart and metal goes all over the place. With the balls finally somewhat or more free due to the lack of an effective cage, the intermediate shaft gear pushes the output shaft front (5th) gear towards the right side of the transmission....and thus the shaft moves to the left. This will, if bad enough, result in the output flange on the transmission (driveshaft U-joint flange) contacting the transmission lip area where the boot is, and the output rear bearing distorts......and with metal getting into things.......all sorts of mechanical mayhem happens, and rather fast. From the first sign of unusual vibration, things deteriorate rather quickly. If allowed to proceed much at all, gears, bearings, shift fork, and even the rear case of the transmission, are ruined.

This point of view is quite different. I do NOT agree with this view. This view is that while the helical cut gear does move forward under load, it presses the inner race of the bearing, and it takes that load because the outer ring is against the gearbox case....and thus the circlip is of no matter. Thus if the clip IS there, the entire shaft moves forward, and the bearing always takes the axial load, and no force moves the inner race relative to the shaft. This point of view is thus that the smaller bearing should fail first if preload was a problem....and....there are NO circlips on any of the other shafts....and, further, the purpose of the circlip was to assist with disassembly! During the heating of the transmission, the case should release all bearings, but a circlip-less large bearing COULD remain in the case when the shafts are removed, and it is a bit of work to remove the bearing...that one, as it is larger, sticks in the case recess... so the clip was used. These folks agree that the clip removal coincided with the increased bearing failures....but say that the increased failures are NOT caused by the clip removal, it was coincidental with the Paralever introduction. They say that the GS Paralever introduction, with its extra travel, puts forward thrust into the gearbox, and even an angular thrust due to the changed design (dual travel angles of the Paralever), and that said angular thrust is taken up by that large 6403 bearing.....and 'proof' is that no extra large REAR bearing was installed by the manufacturer. Thus, these folks believe EXTERNAL forces are the cause for the gearbox failures, and they tend to blame too high spring preloads and poor lubrication on the splines. They feel that BMW put the circlip method back into production as it was cheap to do, and shows that BMW 'did something'.

MY viewpoint: The above #2 viewpoint is faulty. Circlip-less gearboxes on NON-Paralever have certainly failed in this area....negating the above arguments. ALSO, I know of NO failures of any gearboxes in the fashion mentioned in this article that were not fixed permanently by modifying the shaft and installing the circlip (with new bearings, etc....as required). So...I just can't buy this argument; especially when considering the thrust given by helical gears..

Note: It has been reported to me that the stock Paralever driveshaft has exactly the same pivoting length as the swing-arm, assuming the rubber damper is OK, and as long as that is intact, there are no axial forces on the output shaft. Another reason for negating some of argument #2.

NOTE regarding that previously mentioned 'special 6403-C3 bearing' for the front of the output shaft: It appears similar to any other 6403-C3 bearing, but the front face of the inner race (forward edge of the inner race, the side of the bearing which has writing on it) is cut with a 90° angle (much smaller taper to it than the rear face of the inner race) between the face and the inner hole where the bearing slides over the output shaft instead of the 6403-C3 bearing which has a tapered angle. The forward taper is almost absent. Perhaps this was done to minimize the possibility of bearing creep as the bearing is pushed against the retaining circlip by 5th gear. This modification may well have never been needed. The regular bearing worked fine, never a problem with bearing creep leading to bearing axial overloading....UNTIL BMW started leaving out the bearing retaining clip. This new bearing MAY be the accepted choice....but: The more commonly accepted view is that the elimination of this cheap clip and associated groove caused the problems...AND...the last word I had was that if one now orders the 'special bearing', you get a STANDARD 6404-C3, withOUT the modified inner race face. The 'special bearing' was used only for awhile, and BMW went back to the regular old bearing???

Generally speaking, modifying the shaft, installing the clip, new bearings, seals, re-shimming, etc., will be very favorably priced, compared to just a new shaft from BMW! Those doing their own overhauls can have a good machinist cut the groove to accept the snap ring. Re-shimming is, of course, necessary with new bearings, etc.

Here is an EDITED (by me) query and reply, as was on the Airheads LIST in November 2004, that will explain about one little thing you might otherwise overlook, if you are overhauling your own transmission:

The transmission was a 1983 or 1984 R100RS. The owner decided to do an overhaul ...it had been done previously, probably by him, and the mileage was now around 200,000 km.    He noticed a small "rumble" or notchiness in the output when revolving the output flange, the driveshaft shaft disconnected. No sound, no notchiness when tested from the wheel with the driveshaft connected. A transmission oil change (done every 6 months!) showed normal metal powder on the drain plug magnet.

Tranny was removed and he slightly released the gearbox cover screws (1-2 turns) and the notchy feeling disappeared totally. Sounds like a preload problem??    The owner then measured the clearance between the output shaft snap ring and the big bearing (6403) inner race; the inner race pushed as far as it goes down the shaft. A 0.25 mm feeler gauge was a bit tight but a 0.20 mm loose. So, he concluded that there must be more than 0.20 mm "undefined" clearance in the shaft and it seemed to him that there is no reasonable way to shim the shaft within 0.1 mm as required especially if the bearing may drift along the shaft. The owner then felt that he would have to shim the snap ring and the bearing inner race to zero clearance.

The owner continued....(my editing here): My actual question is about the "bearing drifting along the shaft due to missing snap ring" theory: If the front bearing inner race moves along the shaft (despite press fit) ...what... is holding the shaft in place ...that the drift can take place?   If it is the smaller bearing then the snap ring push will really prevent big bearing drift but this may cause a situation where the shaft drifts in the smaller bearing, not the big one. Again, a preload will result. He also wanted to know what happens to the bearing outer races in operating temperatures? Do they float ie. are they free to move away from their assembled positions? The operating temperature is not very far from the assembly temperature where the bearings practically can be dropped in their places.

Tom Cutter replied: There are several forces at work that can dislodge the bearing inner race from the shaft. One is the weight and forces of the driveshaft as it undergoes normal rotation, the forces placed upon the output shaft are cyclical, both rotationally and axially.   The bearing is designed to be captivated by the clip to preclude ANY axial movement of the bearing race upon the shaft. Unfortunately, the bearing now sold for the output shaft is dimensionally slightly different from the one designed for in the original plan. That bearing had a square corner on the rear face of the inner race, so that it would press evenly upon the circlip. BMW only offered that bearing for a relatively short period, then they substituted a standard 6403 C3 bearing in its place in the parts system. The standard 6403 bearing has a VERY generous radius on the inner bore, which makes the race bear on the very outer edge of the circlip. In some cases the clip becomes dislodged into the adjacent void. The problem is exactly as you have mentioned, and is the cause of the premature failure of so many gearboxes. The cure is to shim the inner race so that there is no possibility that the bearing can be displaced. This can be done with flat shims, although BMW do not offer such, or by simply fitting the round wire expansion ring that BMW used for the purpose.   Emphasis in red by snowbum

This round wire expansion ring sits down in the radius of the bearing bore, and effectively fills the void so that there is metal-to-metal contact from bearing to circlip (snap ring). The circlip is: 07-11-9-934-100 (size 17 x 1). This is the same circlip used on the shift shackle in the transmission, in case you get curious about it.

The round wire expansion ring is 23-21-1-235-006.
BMW uses the term Expansion Ring for the wire spacer at the bearing under discussion, and the word circlip or snap ring is the part that goes into the shaft groove.

The output shaft groove is 1.01 mm wide and 0.5 mm deep, located at 17.00 mm from the step on the forward end of the shaft where the 6403 ball bearing sits. Machining should be by 1.00 carbide tool. Be sure to check your shaft, and these numbers, don't trust ME here.

One thing to really think about is what to do if you think you have a transmission withOUT the circlip. Whilst I am attempting to identify the full range of serial numbers, year, model, etc., that for sure have no circlips, it still remains a bit wishy-washy, although less so as time goes on. You do have a choice on what to do, or not to do. One choice is to remove the transmission and send it to someone like Oak Okleshen...or Ted Porter ...or Tom Cutter...or Bob Clement.....as a preventative measure. One can help oneself feel good about doing that early sort of thing with the understanding that as the transmission fails enough, it puts bits of metal filings all through the transmission, doing a lot of damage.
You could also take the attitude that you will watch things carefully, and at the first sign of problems with your OFTEN inspected magnet that is part of the stock drain plug (and, disconnecting driveshaft and rotating the output flange as noted in #5, way above)....you will pull the transmission and have it modified and overhauled. You would also carefully be watching for sudden vibration....and have promised yourself to stop right then....not proceed another few miles....

Some tolerances on some transmissions throwout area bore sizes, and throwout pistons, were not held tight (well, LOOSE) enough. Generally this is thought of as from 1981, when BMW changed the clutch design radically. If the piston fits into the bore a bit too tightly...it may still operate smooth enough, but under some circumstances (temperature, as in HOT!) may stick. Measure the piston, and if it is over about 1.13" (28.7 mm), you MAY want to reduce the outside diameter a bit. I have seen these as large as about 1.142" that still worked OK. I can't give a hard and fast rule here, but if yours is up to 1.141 or so, I would certainly see how it fits, and if a bit too much friction, I would recommend sanding the OD a bit. The pressure on them in operation is rather square, so if any doubt, ....if careful... you can chuck the rather short shaft tip end in a drill press and use some rather fine sandpaper for this. Inspect the bearing, and if it looks bad, replace it. Grease it with a good LIGHT grease (NO moly). The reason to use light grease is that it takes time and miles for the transmission OIL to reach this throwout bearing. Oil the outside of the piston as you assemble this area. Clean and lubricate the arm and associated parts. BMW has a replacement piston: 23-13-1-464-167 which is pricey as it includes the bearing and is a new design, that eliminates the clearance problem of the old style piston...but you do NOT need to purchase it, unless you cannot find a new old-style bearing (if YOUR bearing is NG), or, you don't wish to sand YOUR old piston (if required).

NOTE that the original piston is not a one-piece part, rather, it is a part-plastic item, and it expands much faster than even the surrounding aluminum alloy, so common 'feel' for clearances may end up leaving it too tight. The updated part fits directly, no problems.....measure and decide. I sometimes test the fit with the transmission at operating temperature.

NOTE!!....There is much more extensive information on the clutch throwout lever, the bearing, etc....be SURE to see it on this website! clutch.htm
That article has a photo of the later style clutch throwout parts, and the actuating rod, and notes on the FELT on the pre-1981 rods, ETC.

Note: Sometimes I am asked about the various years of transmissions, good points, bad points, etc. A lot of information is in the article you are reading. However, the 1974 transmission is a special instance. This was a transition year for BMW, from the /5 to the /6, and there were some things not so nice for 1974. For example, the 10 mm flywheel bolts were retained (later to go to 11.5). 1974 was the first year for the 5 speed box. The Pawl springs tended to break. The kickstart parts were SOFT...and use of the kickstarter is NOT recommended. There were problems in positively locating the Neutral position, and that wasn't fixed until 1976. The 1974 transmissions, in other words, did not hold up well. Some parts are no longer available. If a 1974 transmission is really bad, one might want to consider a brand-new one; or, preferably, a really expert rebuilt one...as the price is less, and the quality will be BETTER than a brand-new one!. 1981 was also a bad year.

1. Pawl spring breakage fix: turn down the boss it rides on about .060". SEE #9 below!
NOTE: Inside your 5 speed transmission, are a few springs. There is a detent spring, that enables the shifting mechanism to shift gears. If that spring breaks, which is NOT all that uncommon!....you are stuck in whatever gear you happen to be in. You MIGHT be able to remove the fuel tank, turn the bike upside down, and then shift into a gear...maybe. I've heard of this, never done it myself. All the 5 speed transmissions up to the early 1980's could have this spring breakage defect. The post the spring is on has had its diameter changed in the 'shift kits'. You can certainly reduce the diameter of the stock type. The spring must not bind-up in its operation.
***The so-called shift-kit parts, Pawl 23-31-1-242-892; and Segment 23-31-1-231-578, supposedly will 'cure' broken pawl spring problems....but modifications work well, AFAIK.

2. NOTE!!! see article: oiltransfers.htm The output shaft oil seal on all models except the Paralever, have the open side facing rearward. The Paralever output shaft oil seal open side faces INward.

A new style seal is being used on the Paralevers, install dry, shaped for a couple hours on some sort of mandrel, and then being very careful abouit the installation, to avoid the seal being damaged by the speedometer drive. You can use some tape over the drive gear to avoid damaging the seal. If you have an early model of the Paralever, there may be a goodly sized V-vent at 12 O'Clock in the housing. Block this vent and drill it 1mm. Later models have this already modified. Wet driveshaft models used a green seal. If you have oil transferring from driveshaft to transmission, you have one or more of: too high driveshaft oil level; sacked suspension; extreme downhill riding; ....and may want to fill the 12:00 notch....with a teeny hole in the filling. You MUST have a hole.

3. In April of 1982 (from serial 58225 on the transmission??) the helical-cut gears in the transmission were changed from 15° to 17.5°. The new 17.5° gears are identified by a cross or star or X marking on one end. They are NOT interchangeable with the older 15° ones, and only 17.5° matching gearsets can be used. Supposedly BMW also identified these updated transmissions with blue paint dot on the airfilter housing surface of the transmission. However, the later transmissions do have serial numbers on the outside, check for yours under the air cleaner box on left OUTside. From 115167 (from April 1985?) the input shaft assembly was redesigned. The earlier gear had a smaller ID, and fit the smaller input shaft OD...with short splines. The reason for the second generation update was because the first generation of the 17.5° input shaft gears (4/82>4/85) were weak and the drive ears might break. These updated parts can be fitted to an earlier gearbox with the 17.5° gears. The original fragile input gear is still available from BMW. However, the best thing is to install the complete second generation input shaft assembly. The part is 23-21-2-302-331 if you have no kickstart gear; and 23-21-2-302-332 if you do have the kickstart gear. I have NOT YET confirmed those numbers. Supposedly these transmissions are identified by a black painted panel in the ribs in the aircleaner mounting area. Note that in one other respect the input shaft used on the 1981+ models is not the same as the older gearboxes, due to the redesign of the clutch, etc., the earlier ones have a longer nose, see #8 below. Thus there was at least two changes to the input shaft.

4. Only the 1970 and 1971 transmissions did NOT have the tiny notch for breathing, at the transmission output seal 12:00 position. Because of that, the driveshafts on the 1970-1971 bikes tend to have their 'rubber' bellows swell up in hot weather riding. This slight pressurization can also cause oil transfer problems. An article was written about this, and is in the September 1981 BMW News. The only GOOD cure is to add the transmission output vent...a drilled hole or hand-filed hole will do. Other forms of venting, even modifying the driveshaft oil plug, etc., do NOT work well (even with a several inch long line run upwards). The shaft housing could be vented in the more forward area, but the BEST fix, if you have to fix this problem, is to put a vent in the tranny output area, as in later airheads.

5. There are quite a few 'tricks' and adjustments that don't readily appear to someone taking apart a gearbox. For a truly good operating gearbox, you WILL want to consider a specialist. I've named them, well above.

6A. The 1974 transmissions had a soft kickstart gear on the input shaft, which can cause problems. It is best to not use the kickstarter, except in an emergency. A replacement part will be hardened.

6B. The /5 kickstarter shaft inside the transmission has a tendency to loosen, and move INwards. You can see that from looking at the rear of the transmission. DO NOT allow that to happen. The easy fix is to drill the center of that shaft at the back of the transmission, thread the hole, and add a large flat washer, larger than the shaft diameter, and use Loctite BLUE or RED on the STEEL screw you will add to hold the washer to that shaft. That prevents the shaft from moving inwards. Use some sort of goop sealant between the washer and shaft/case, to stop any possible oil leakage.

6C. The kickstarters are not really meant to be used a lot. The 1974 was weak (see 6A.). NEVER just jump on the kickstart lever. Be SURE it is properly engaged. MY method is to use light foot pressure, until the lever seems to engage, then use the clutch lever at the bars to allow the kickstart lever to move downward an additional small amount. This ensures proper engagement. Release the clutch lever. KICK.

NOTE!! The kickstarter lever on /5 and later will 'bottom' on the footrest rubber. It is important that it not be a pure metal contact.....and on the /2 bikes, there is a rubber bumper. The rubber must be intact.

7. The improved shifting setup, with the external linkage mounted off the footrest is probably still available as a kit, for the earlier 5 speed transmissions. The design change occurred in 1978.

8. In 1981 BMW made changes in the transmission clutch throwout bearing area, internally as well as the external shift lever arrangement. Also in 1981, BMW made a large change to the clutch and flywheel, which became a totally different design, and the flywheel is now called a Clutch Carrier....and the transmission input shaft was changed to accommodate those changes. Transmissions before and after that date can be interchanged if the input shaft is the correct one.
The input shaft is about 24 mm long on the early transmissions, and from 1981, it is about 19 mm long.

It is also possible to shorten the input shaft on an early transmission, in order to fit it to a later clutch unit...by simply using a cutoff disc, etc., even with the transmission still together!

Within certain guidelines, such as the input shaft length, and internal gears angle cuts, shift kit or not, proper neutral switch...etc...as all mentioned in this page, all the transmissions generally interchange.

9. In mid-1982 (could be during the 1981 production year, this is unclear to me) BMW installed a so-called 'shift kit' inside the transmission....this is a fairly extensive kit with a revised cam shape, modified shifter arm, etc. It is retrofitable, and should be considered for earlier transmissions when overhauled. Its purpose was to eliminate false neutrals or hung-up shifting, and improve shifting in several ways. The kit is part number 23-31-9-056-150. Later transmissions incorporated these parts. The parts were included in transmissions FROM serial number 56476. It appears the kit, but not the individual parts, are NLA. SEE THE ADDENDUM NEAR THE END OF THIS PAGE FOR MORE INFORMATION ABOUT AN ARTICLE ON THIS SHIFT KIT!!
NOTE!!!....The "shift kit" is most effective on the 1981 and 1982 models (to maybe 1983, depends on exactly when BMW phased in the shift kit themselves, on the various models), because these have the lightened Flywheel, called a Clutch Carrier. The shift kit might improve earlier transmissions slightly, and maybe slightly even more IF the early heavy flywheels have been considerably lightened. The shift kit does much less for those with the heavy flywheels. The shift kit did NOT come with any instructions.

BE SURE that in your assembly of shift kit parts that the arm is doglegged, that is, off-set.

The shift kit is made up of the following, still available parts:
23-31-1-231-578 segment shaft
23-31-1-231-611 shifting cam
23-31-1-242-892 pawl
23-31-1-242-910 spring
23-31-1-451-563 shifting cam

**NOTE: use of the shift kit REQUIRES use of the later LONGER neutral switch, or the neutral switch electrical functions will be in reverse of what they should be! The later switch is 61-31-1-243-097, and a spacer 61-31-1-355-262 is used... perhaps TWO.
The 1974-5 neutral switches have a shorter stem. If you install the wrong switch, it does not work correctly!

***The so-called shift-kit parts, Pawl 23-31-1-242-892; and Segment 23-31-1-231-578, supposedly will 'cure' broken pawl spring problems....but modifications work well, AFAIK.

NOTE! There is are TWO sections in the ElectricalHints.htm article on this website on the neutral switches, neutral lamp, starter circuit, and problems. It is complex!

Here is something from that article, but please read the entire article!
ALL Neutral switches are CLOSED in neutral, turning on the green neutral lamp (enabling the starter function if the starter button is pressed on 5 speed transmissions). The reason for the shorter and longer neutral switches is that in the early shifting parts, the switch rode on a section of the cam that was, in essence, a projection, and the switch itself helped make the feel for the 'detent'. On the revised parts, neutral is much more positively felt, by the switch being in a 'valley' of the shifting cam, hence the switch is longer.

Read the article!....IF the diode shorts, then the lamp is ON if the lever at the bars is pulled. There is a peculiarity with the 1978-80 models, which have a master cylinder under the fuel tank. These incorporate a float switch, whose purpose is to illuminate the brake failure light if the fluid runs low. The lamp gets tested each time you start the bike, via a diode. If the diode shorts, and you are also low on fluid, the starter could theoretically energize.

Tom Cutter posted the following to the LIST in September 2003, and it clearly states what the kit also does, and I quote (typos corrected by myself) ((comments by me, snowbum, are clearly marked in BOLD RED)):
"The kit includes a selector arm that has a second rail which will then will allow shifting, albeit a little sloppy, in the event that the spring fails. ((note inserted here by snowbum: I do not believe that to be so, the second arm being designed to prevent overshifts and false neutrals)). In my opinion, when the spring is properly installed and the stress relieved, the failures become non-existent. Nonetheless, the new arm is a nice fail-safe piece." ((see above note by snowbum, who believes the new arm is not a fail-safe piece as such)). Tom later added the following: "The repairs ...referred to are only necessary if one is retaining the older shift pawl. If using the new shift kit, which I highly recommend be fitted at the same time, the parts are upgraded and don't need modification (Or they are supposed to, I found one old shift pawl in a shift kit recently). ((Snowbum says: Interesting, if true. The old pawls were gone decades ago, no one else seems to have found wrong parts in the shift kits)). I am trying to describe this so it will make some sense, but basically, the spring gets over-stressed when it wraps around the boss on the pawl. The boss can be ground to a smaller OD, and the spring attachment point can be modified by grooving the plate, to prevent the spring coil-binding on the boss. ((Snowbum says: The boss was a problem in the 1974, and maybe some 1975 production, and the oversize boss was fixed no later than sometime in 1975; the springs break from improper heat treatment, or fatigue, or too soft or too hard, maybe brittle....seems to be a difficult part to manufacture correctly?)). Either or both methods work fine. The important thing is to assemble the shift plate mechanism, then pull the shifter hook arm back as far as it will go, while looking at the pawl spring. If the spring is binding, it will be apparent. This must be corrected." ((snowbum says: doesn't happen on 1976 and later)).

NOTE: Early/Mid-1982 is not a cut and dried statement. BMW has a habit of phasing in changes, and on occasion one might find a far later serial number withOUT the change (to incorporate the shift kit). But, that said, the 1984+ transmissions had the transmission serial number on the left outside, just under the airbox fitting surface, at the air tube to the left carburetor area. The earlier transmissions had the serial number at either the rear top, or front top, but you must pull the airbox to see the number. You will do that at the spline service anyway. The serial number for the beginning of the shift kit is: 56477

10. The 4 speed transmission can be a devil to find parts for, and to overhaul correctly. I strongly suggest going to one of the experts shown below, in particular Oak, Bob Clement, Ted Porter, Tom Cutter and Matt Parkhouse. In fact, those are my recommendations for any BMW transmission.

1st                4.44                                3.38
2nd               2.86                                2.43
3rd                2.07                               1.93
4th                1.67                                1.67
5th                1.5                                   1.5

12. There is an additive that works modestly well in the transmissions to smooth the shifting, particularly with transmissions with the original older style shifting parts. Do not use this stuff with synthetic oil. It is Dow Corning M Gear Oil Additive. Comes in quart bottles. Shake well and use up to 2% concentration max, not the up to 10% Dow suggests....so, the amount to use is about 18 cc for the airhead transmission. This stuff is VERY expensive. DO NOT use with synthetic oil and do NOT add more than 20 cc.

13. The 5 speed transmissions have, on the input shaft, a cam and spring shock absorbing system, and one of the gears, that has the cam on one end, is 23-21-1-231-519. This gear MUST be replaced if it appears to have worn such that it looks even vaguely questionable; the replacement gear from BMW is hardened.

14. There is a plastic roller on a shift lever in the transmission, it is 23-31-1-231-572 and tends, over a long period of time, to start to fail; the steel one from the K is 23-31-1-451-087, and I have recommended it in the past. I am not so sure about this, now, as I have heard, ONCE, of the steel K bike roller causing wear against the lever it touches...and perhaps there is some heat treatment variation on that lever...or? NOTE: if the roller fails, the transmission may well exhibit jumping out of gear. This can also happen if the associated spring breaks.

15. In 1977 BMW made changes to the transmission. The slider gears shifting fork grooves were made narrower, now 5.7 mm, previously had been 6.5 mm. The 3rd, 4th, and 5th gears now had square doglegs (undercut). The detent spring was changed....and it has 5 turns. The camplate was changed. The casting was changed for better selector fork shaft support for 3rd and 4th, and the shaft which had been 100 mm is now 105 mm long.

***Transmissions are best overhauled by an expert with a lot of experience. For the person who definitely wants to try doing a transmission, you can do it under tutelage or perhaps get Ed Korn's video, ETC.

axial float on all shafts: 0-0.1 mm (0-.004 inch)
gear change lever shaft axial float on 4 speed: as above
fork bolts 17 footpounds
output flange nut 160 ftlbs (clean and dry on the tapers!...absolutely NO residual oil!)
end cover nuts 6 ftlbs

4 speed transmission:
   Output shaft, drive (rear) end, type 6204C3, 20 x 47 x 14 mm. This WAS part number 07-11-9-981-219, and that changed to   07-10-1-468-880
   other (front) end, type 6403C3, 17 x 62 x 17 mm. This WAS part number 07-11-9-981-505, and that changed to 23-12-1-338-795. Used on both 4 and 5 speed gearboxes. SEE remarks below for 5 speed transmissions!

   layshaft (also called the cluster shaft or intermediate shaft), cover (rear) end, type 6203-C3, 17 x 40 x 12 mm, the part number is 07-11-9-981-214.
   clutch end double row type 3202 in some books, but is 3203C3 (aka 5203), 17 x 14 x 17.5 mm. This WAS part number 07-11-9-982-409, and that changed to 07-10-1-468-914.
   Input shaft, both (front AND rear) are type 6304C3 20 x 52 x 15 mm.   Part number 23-12-1-232-695. Used on both 4 and 5 speed gearboxes.

This is an EDITED repeat of a NOTE, from considerably earlier in this page:
Regarding the 'special 6403-C3 bearing' for the front of the output shaft: It appears similar to any other 6403-C3 bearing, but the front face of the inner race (forward edge of the inner race, the side of the bearing which has writing on it) is cut with a 90° angle (much smaller taper to it than the rear face of the inner race) between the face and the inner hole where the bearing slides over the output shaft instead of the 6403-C3 bearing which has a tapered angle. The forward taper is almost absent.   Perhaps this was done to minimize the possibility of bearing creep as the bearing is pushed against the retaining circlip by 5th gear. This modification may well have never been needed. The regular bearing worked fine, never a problem with bearing creep leading to bearing axial overloading....UNTIL BMW started leaving out the bearing retaining clip. This new bearing MAY be the accepted choice....but: The more commonly accepted view is that the elimination of this cheap clip and associated groove caused the problems...AND...the last word I had was that if one now orders the 'special bearing', you get a STANDARD 6404-C3, withOUT the modified inner race face. The 'special bearing' was used only for awhile, and BMW went back to the regular old bearing???
   see above, 4 speed transmission, for bearings used on both 4 and 5 speed gearboxes.
Continuing with the 5 speed transmission:
   Output shaft, input (front) end, type 6403 (see 4 speed) (see above too!); and the output (rear) is 6304 (see 4 speed).
   Layshaft (Cluster shaft or intermediate shaft), both are 6304.
   Input shaft: Uses special bearing #NU204E at the front, and a 6304 at the rear
NOTE that the 6304THNC3 bearing is used, part number 23-12-1-233-807

Here is some reference material, and comments:
1. In the September 2003 issue of BMW Owners News, from page 34, is an ILLUSTRATED article on replacing a broken Pawl Spring in the transmission. Just a couple of comments by me: In illustration 15, the torque obviously should not be 24 foot pounds.....5 to 6 footpounds is correct. In the article, the author does not mention that the BOSS needs to be relieved to be sure the spring does not bind up and break, again! See item #1 and #9, etc., way above, herein.
2. In the November 2003 issue of BMW Owners News, from page 34, is an article on installing the updated shift kit. There are some errors in this article:
    a. In the first column of page 34, second paragraph, the kit does NOT NECESSARILY allow shifting with a broken spring.
    b. On page 34, photo #1 text, it is NOT true that there are no differences.   There IS a design change. The 1974 and 1975 had a reverse neutral....that is....the plate PROTRUDED at neutral, rather than being DETENTED. The new design makes finding neutral much more distinct and positive.   The Neutral switch was changed, and although they look similar, they are not.   The newer plate shaft is changed to insure against clashing with the pawl arm. Photo #3 text should not really have the second sentence worded like that.
    c. On page 35, photo #4 text, it is NOT true that there are no differences. The new arm has an offset to avoid binding.
3. In 2005, Matt Parkhouse did a series of articles in BMWMOA-ON, on overhauling the 5 speed transmission. GOOD stuff.

This is a reference to Anton's transmission article. It has a listing of parts, some photos, including of the shift kit items, ETC.   This site will further your education on the 4 and 5 speed transmissions. Anton also lists some of the many changes BMW made to these transmissions over the years, what can and cannot substitute and what won't fit, etc.    Highly recommended:   http://www.largiader.com/tech/airtrans/

Tools and video for transmission work, and other work:
Ed Korn
Cycleworks, Inc.
4812 Goodland Park Road
Oregon, WI   53575
608-246-0404
www.cycleworks.net
Edkorn@usa.net

Transmission and all other work (meticulous workmanship):
"Oak" (Oak Okleshen). I can recommend OAK for ANY type of airhead work.
Meticulous craftsmanship, and very high knowledgeable. Perhaps THE most
knowledgeable Airhead tech in the USA.   Official Friend of the Marque.
22637 S. Ridgeway
Richton Park, IL   60471
askoak@aol.com

Ted Porter's Beemer Shop, on the West Coast.   Ted has a deservedly
solid reputation, and was with BMW.
www.beemershop.com
34 Janis Way
Ste E
Scotts Valley, California
(831) 438-1100

Bob Clement. Good craftsman. Reliable quality work.
Bob's Motorwerks
often just referred to as BMW-Montana
91 Blanchard Butte Rd.
Roberts, MT 59070
406-445-2044
bmwmontana@aol.com

Tom Cutter's Rubber Chicken Racing Garage
Tom has a lot of experience going back many years on BMW bikes,
and does a lot of gearboxes as well as other Airhead work.
1360 Colony Way
Yardley, PA 19067
shop: 215-321-7944
cell: 215-206-9787
Tpcutter@aol.com

Matt Parkhouse. Well experienced long-time Airhead tech who writes
articles for BMWMOA magazine, etc. Very helpful, solid background.
HOBOMATT@aol.com
EuroCityCycles, Colorado Springs, CO.
719-635-3004

The following is known to me only by hearsay:

Charlie Johnson
BMW Motorcycle Service
(all models)
18145 Hummingbird Road
Wayzata, Minnesota
(952) 449-0357

Wuma, Inc (Guenther Wuest)
wuest@blueriver.net
6891 W. US Hy 150
Fredericksburg, IN 47120
812-472-3739
He ALSO does conversions to the 5 speed transmissions; information on this conversion will be found in the SidecarURL.htm page on this website. Motorren Israel also does different type of reverse gear conversions.

Motor Works, Inc.
1490 Island Ave.
San Diego, CA 92101
619-233-8875
motowrk@adnc.com

07/07/2008: all prior updates incorporated, and, minor editing for clarity; and include groove depth; add
hyperlink to Anton's site