This page is mostly about the BMW motorcycle models R26, R50, R60 and the
famous R69 from the start (late 55) to mid 57.
The Earles forks were mentioned in an owners manual in 1954, so they had
already been tested and approved for production. They were specifically
called constant wheel base forks for sidecar use. They were introduced in
55 in Europe and a bit later in America. Not all models were available
with Earles forks from the start. BMW was probably selling off old stock,
before releasing the new models.
This is a sales brochure, in English, that promotes the R25/3, R50, R69 and
the R67/3. The print date is 1/55.
Weaknesses appeared in the new models and changes followed in mid 57.
The 56 to mid 57 BMW twins are quite different than the mid 57 and later ones.
BMW's advertisements called the changes (read "fixes") the "accessory group."
Here is what I remember of the changes.
1. The biggest is the transmission. All bikes were equipped with
sidecar gearing as standard. The solo gearing was optional, maybe only in
the R69. The sidecar transmission has no mark on it with the "S" meaning
"solo." The mark is found in two places. One is just in front of the drive
for the speedometer. The sidecar transmission will have no "S" on that
horizontal flat place. In first gear the bike should only go up to a about
15 mph and then you must shift. If you must shift out of first by15 mph
then you have the correct sidecar gearing. In mid 57 all twin models had
the gearing marked "S" for Sport. From the first models in 56 the sport
gearing was an option. Starting in mid 57 the sidecar gearing was an
option. The first picture below shows nothing in the horizontal flat spot.
The later sport transmission was marked with a "S" in two places, the oil filler
plug and the speedometer drive. They can be seen in the middle and right
How does one know what the ratio is if the bike can't be ridden? Easy,
measure the number of rotations in first gear. Carefully shift the
transmission into first gear. Make a mark on the top of the input shaft
and output shaft flange. I use a magic marker. Carefully rotate the
input shaft and count the turns to get the output flange to go around once.
The sidecar transmission will take 5.3 turns and the sport transmission will
take only 3.7 turns. If the transmission is still in the bike then mark
the flywheel and count the revolutions. Peel back the driveshaft boot and
count the revolutions of the output shaft.
2. The speedometer is marked with shifting points for the wide ratio
sidecar gearing. I forgot to take a photo of it. I will get it soon.
3. The spoke pattern for the wheels is different. The older ones
spokes cross each other near the hub, not in the middle of the spokes, as in the
later version. The spokes are smaller diameter, 3.5 mm, not the later and
stronger 4 mm. The spoke called 3.5 mm actually measures .120" and the 4
mm spoke is .136". The hub, rim and nipples are of course different too.
The wheel bearing system is the same.
In Europe the two spoke patterns are known differently. The early type
has the spokes crossing in only one place and is called the "one cross".
The post mid 57 type has the spokes crossing in two places and is called the "two
The older spoke pattern.
4. BMW increased the battery size. The older battery is very
small and is almost square. It is 90 X 80 X 162 mm high. The box, or
holder, is also small. The battery strap is shorter too. Forget ever
finding one of those. The larger battery was commonly added to these
models. Generally we didn't change the battery holder to change the
battery to the larger one. We just bent the side locating tabs flat.
You can bend them back up if you find one that has that mod. This larger
battery was for the USA and all bikes that I saw from Europe still had the
smaller battery, until at least up to 1968. It was 120 X 90 X 165 mm high.
5. The older headlight ears are smaller and they broke easily and most
have been replaced with the newer wider ones. The difference is where the
ear widens out to meet the part that is bolted onto the fork down tube.
The later one is about 3.5 " wide and the earlier one is about 2 3/4 " wide.
The narrow one cracked vertically at the place right behind the chrome 14 mm.
bolt that holds the headlight. Just where it starts to widen out.
This is the early one.
6. BMW increased the leverage on the rear brake shoes. On the
final drive is the brake arm that is vertical and holds the long adjustable rod.
The correct older one is very short, about 1.25" center to center, of the
shafts. The later one is about 2.10" center to center. The short
ones were painted black and the longer ones were cad plated. The early
brake rod was also painted black. The change was made to get more power to
The short brake arm.
7. The older front fender has only two mounting points, front and rear.
The later fenders have a mid point mount, a flat brace mounted just behind the
shocks. This fender, when removed, has no brace on it at all. The later
fender has the brace riveted to it. This braceless fender was also used on
the R26 and R27 until the end of production in 66. A bit odd that the
fenders without the brace was used on the two models that vibrated the most.
8. They continued using the very small tail light that had been used
since the late 30s. It was replaced by the one that we know so well as /2
"coffee can." The small light has a glass lens. The larger coffee can lens
9. Some of the bikes that were equipped with solo seats, had a coil
spring and not the commonly known rubber "silent block". This spring was
abandoned very quickly, well before the mid 57 "Accessory group" changes.
This seat is very rare and I have only seen three of them. Don't even ask,
this one is not for sale.
Other changes, but not limited to those early models
Not part of that series change called the "Accessory Group" were a few other
things you must have to be correct. These items were used until they ran
out of them.
1. The little half moon cover that hides the small air cleaner for the
air that is drawn on over the engine electrics is held on by a fancy knurled nut
of about 1" in diameter. This small round filter was used up until 1968 when
BMW just deleted it, probably to save money. Check back here later and I
will have photos.
2. They were still using the older style of headlight shell from the
R25 single. It had a 3-4 " big round "dent" in the rear of it. It
was hard to see as it was at the lower rear and was for clearance of the R25
horn. They just "used them up" and then began using the ones without the
dent. I can't say for sure when they changed that part, but the old ones
all had the dent. The ones with the dent were available as spare parts for some
time. I bought 20 of them at "close out" from Bosch in 1968. I used
them whenever a customer needed a new shell. This has caused some
confusion as to what is "correct".
3. The pre 1961 headlight glass had a big "U" cast in it. The
older (back into the 20s) the BMW is, the more pronounced that the "U" is.
The "U" is seen around the lower part only about 1/2" in from the edge.
The upper parts of the "U" terminate at about 10 and 2 O'clock. The lower
40% of the glass has a mottled look or patina cast into the glass.
4. The Bosch motorcycle headlight rim has the manufacturers name on the
top, in plain sight, "Bosch Alamagne" or something similar.
5. The valve covers are very thick and heavy with casting "flash" lines
in them, extending from the ribs straight horizontally out to the edges.
In about 61 the flash lines disappeared. In 68 and 69 they had very light
and thin covers. From 56 to 69 they had 3 types of valve covers on the
twins. The R50S had it's own cover, as did the R69/R69S. The singles
had two piece covers for one head.
6. It should have the heavy horn, not the later "light weight" one.
I don't remember the year of that change. Can anybody help out?
7. There should be no 13 mm fasteners anywhere on the bike, only 14 mm.
The first 13 mm fasteners showed up in 63 and by 65 no 14 mm were being used on
8. The carbs must have the small diameter outside float chambers.
BMW changed to the carbs with the larger chambers in 63 to accommodate a sidecar
rig going through a very long curve.
9. The very early air cleaners were more square than later. The
air cleaner comes apart to access the filter element. The upper part has a
square corner and later is quite rounded off.
10. The early final drives had no venting system. In 63 BMW added
a vent, or breather, to the top of the housing.
This final drive is on a 56 BMW R69.
11. The early flywheels had a pressed in ball bearing for
the timing marks. Around 1959 they went to the cheaper to produce stamped
See the shiny ball? Those were found up until around the
late 50s on all models. They were on the /3 models too. If you have
proof of the beginning or ending dates, please let me know. Photo by
Thomas Browne, thanks.
The early headlight shell
The R25/3 had the horn mounted just behind and below the headlight shell.
The shell was "dished in," or "dented in" to make more room. The dent is
about 4" (10 cm) in diameter. BMW used this shell for the next few years
on all models that I know of. I do not know when they finally ran out of
them, but I would guess about 58-60. They were available as spare parts
for even longer than they were used in production. Some dealers still had
them on the shelf years later. In 1968 I got 20 of them from Bosch in
Canada very cheaply. Since the shell is black, it is hard to photograph.
Side view of the dish or dent. Photo by Tomas Melander, thanks
This headlight is mounted on my R25/3. This one is hard to photograph.
Does someone have a bike painted a lighter color and with this shell? Please
take a picture and send it to me, thanks.
BMW motorcycle spark plug caps
1. The stock cap used from the mid 50's to about 74. 2. The
plug cap screws onto the plug wire. 3. The resistance is stamped
into the metal covering. 4. The metal covers can be easily removed
to prevent the spark voltage from shorting out. The metal covers are a
disaster in any humidity. I used a cheap rubber cap called "Sparky" in the
old days and have no idea if they are still available. Many owners, back
then, cared little about the originality of the cap. Many didn't want the
large amount of brown showing and preferred the small black caps. The cap
on the /3 series closely resembles this cap with the metal removed.
BMW motorcycle sidecar mounts
All of the motorcycles produced with Earles forks had sidecar mounting lugs
from the factory. In 1968 when BMW supplied motorcycles with the
telescopic forks, the sidecar mounts were not included. This is for a very
good reason. Sidecars and telescopic forks don't work together at all
well. In fact they work poorly together.
That's all I can think of now, I am sure I will recall more and post them.
I forgotten lots of this stuff. I wasn't working on them until 62 and had
to learn all this from one of the most famous shops, Penton Bros. in
Ohio. John Penton was a well known Enduro rider on the R27. He set one
cross country record from New York to L.A. on a R69, in 1961 (I think).
They mentored me and I learned a lot about BMW from them.
If you want a fun beautiful bike, then none of this matters. If you
want a "concourse bike" then you should find as much of the "right stuff" as
possible. I have been a BMW concourse judge at national BMW rallies and
these are all things that matter. A 56 or early 57 without these older
"inferior" parts would be dead in the water.
In 1973 I restored a 1956 R69, and it had taken me 10 years to find most of
the correct parts. At the time I owned the largest repair facility in the
USA for BMW and I had lots of exposure to parts. It still wasn't easy.
My thanks to the current owner, Peter Brewer, for his indulgence in allowing me
to taking these photos of his beautiful machine.
I hope you find some of this info useful. More to come as I remember