BMW R 51/3 Operating instructions
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"R
51/3
·R
67
• R
67
/2
WORKSHOP
REPAIR
MANUAL,
8.AYERISCHE
MOTORENWERKEAG.
MUNCHEN
13'
Introduction
The purpose
of
this workshop repair manual
and
its
numerous illus-
trations
is
to describe the operations required for disassembly, main-
tenance
and
reassembly
of
the R
51/3,
R67
and
R
67/2
motor cycle
models
as
far
as
such tasks
can
be performed
in
well
organized
repairshops with personnel trained
byour
BMW
Service Deparlment.
To
the
appendix
of
this book a
list
is
attached
of
all special tools
needed
for these operations
as
well
as
drawings concerning tools
made
in
the
dealers' own workshops. (Shop-made tools.)
The workshop
repair
manual
is
to
be
above
all a source
of
infor-
mation for foremen
and
mechanics
who
are
in
charge
of
main-
tenance
jobs
on
above
named
motor-cycles
and
therefore it ought
to
be
always
at
hand
within the workshop.
Though this workshop repair manual goes much into the details
of
the
job,
it
is
not expected to replace a thorough training on the
models,
in
our
service
department
school.
For mechanics, however,
who
have participated in the training
course
it
will
be
a very useful reference for special maintenance
jobs
and
adjustment
data.
This
book does not replace the circular-letters regularly issued by
our
Service Department, which should be observed
as
usual.
To
publish alterations
of
technical
data,
tolerances, clearances, etc. no
particular
amendment
service
is
intended for this workshop manual,
but only circular-letters.
Therefore we
may
ask you to kindly insert whatever alterations
we
might publish, so
that
this ....,orkshop repair manual
will
always
be
up-to-date
and
in
conformity with the latest technical developments.
BAYERISCHE
MOTOREN
WERKE
AKTIENGESELLSCHAFT
5e r
vic
e D
epa
r
tine
n"t
Table
of
Contents
Introdudion
Group: Disassembly
and
Assembly
Special Tools
Shop-made Tools
Disassembly
and
Reassembly
Group: Engine
Technical
Data
Fits
and
Clearances
Special Tools
Shop-made
Tools
Disassembly
of
Engine
Crankshaft
and
Cylinder Maintenance
Reassembly
of
Engine
Carburettor
Group: Transmission
Technical
Data
Fits
and
Clearances
Special Tools
Shop-made Tools
Transmission Disassembly
Transmission Maintenance
Transmission Reassembly
Group: Rear Wheel Drive
Technical Dota
Fits
and
Clearances
Special Tools
Shop-made Tools
Disossembling Rear Wheel Drive
Reassembling Rear Wheel Drive
Group: Chassis
Technical Doto
Fits
ond
Clearances
Special Tools
Removal
and
Disassembly of Front
Wheel
Fork
Reassembling Front Wheel.Fork
Group: Side
Car
Attaching the Side
Car
Group: Eledrical Equipment
Our
Motor-Cycle Batlery
Equipment required for Battery Maintenance
Charging
and
Maintenance
of
New
Batteries
Trouble
Chart
Lubricating Chart
Wiring Diagram
Tools
. Special Tools for
BMW
Motorcycles
Drawings for shop-made tools
and
translation
into English
of
German
text
in
drawings.
, ,'Disqssernbly and ,
Assembly
Group'
"
'Special Tools
One
hpok spanner 49
mm
0 for exhaust nut . Matra No.
33811
Shop-made
Tools
One
punch for guiding tube
of
rear
wheel spring assembly W 5013
One
dynamo armature puller screw W 5030
One
assembly stand V 5043
Disassembly
and
Reassembry Group
1
Disassembly
Put motor cycle on the assembly stand (drawing V 5043).
Dhassemblyof
rear wheel drive:
loosen set screws of mudguard stays
and
raise
end
of
rear
mudguard.
Unscrew hub spindle nut
(4)
on
drive side
and
remove together
with washer
(3).
Slacken clamp screw on left axle
holder
and
withdraw hub spindle
axle by means
of
pin
(5).
~--1
Remove wheel. 2
Unscrew winged nut from brake conduit on brake pedal.
Depress pedal so that brake rod slides off the brake arm.
Remove
bolt from brake operating lever, put it
in
the brake rod bore
and
screw
on
winged nut.
On
R51/3 of 1952
and
R67/2 models, unscrew
cap
nuts from upper spring retainers.
loosen
upper clamp
screW
on right
rear
spring bracket.
Remove lower clamp. screw together with nut
and
washer
on
right
rear
spring bracket.
Withdraw right silencer.
Drive right guiding tube of rear wheel spring assembly cautiously from downwards to
upwards by means
of
punch W 5013 (shop-made tool).
Press
rear
wheel drive assembly
to
left downward
and
remove
it
rearwards from the
rubber coupling of the shock absorber.
If
needed, dismount left hub spindle holder
and
spring following the same procedure.
'Disassembly
of
Gear
Box:
Disconnect battery.
Unhook battery holder
and
remove battery.
Withdrow speedometer shaft from drive bushing after
<loosening
its
set screw.
Disassembly
and
Reassembly Group
3
Unhook clutch cable.
Remove thrust spring between clutch lever
and
gear
box housing.
Withdraw induction lines.
Turn out
air
filter holder screw
and
disassemble air filter.
Remove rubber plug from hand change mechanism cover on right side of
gear
box
and
loosen binding screw for neutral indicator cable with a small screw driver.
Withdraw cable backwards.
To
disassemble
gear
box unscrew 3 nuts on rear side as
well
as screw on front
and
save
them together
wi.th
washers.
Loosen kickstarter stop on frame
and
turn
it
outwards.
Withdraw transmission assembly from engine crankcase backwards, unhook retractive
springs for brake operating lever
and
centre stand on
gear
box housing
and
remove
transmission assembly t6 left side.
If
eye for clutch Bowden cable abuts against the frame, unscrew coupling nuts of exhaust
pipes, remove both
rear
and
front engine holding screws
and
loosen upper engine fixing
bolt. Now the engine including
gear
box may
be
lifted on
rear
and
the latter can be
removed. For reassembling, file a trifle the eye for Bowden cable.
Disassembly
of
Engine:
Unscrew carburettor
cap
nut
and
withdraw slide unit from carburettor.
Slacken exhaust pipe coupling nuts on cylinder heads by means
of
a hook
spanner
49
mm
0 Matra No. 338/1.
Loosen feed-pipe by turning out hollow screw on petrol tap.
Dismount protective
cap
from timing case cover after two slotted nuts
are
removed.
Take care that all leads coming from main motorcycle wiring
be
disconnected from
. dynamo
and
ignition magneto.
Push
back carbon brushes of dynamo
and
jam them sidewards by means
of
spring.
Loosen two set screws for dynamo body
and
remove body.
Slacken dynamo armature set screw
and
drive out armature by screwing on puller screw
W 5030 (shop-made tool).
Insert armature into dynamo body (do not put it on winding)
and
wrap
unit
in
clean rags
or
paper.
Protect
it
from chips.
Unscrew upper cover from engine crankcase
and
withdraw disconnected wiring cable.
Turn out engine top clamp bolt.
Loosen nuts on engine
rear
bolt,
remo~e
foot rests
and
exhaust pipe· clips, withdraw
exhaust pipes, drive out bolt
and
remove distance pieces left between frame
and
engine
crankcase.
Unscrew left nut on engine front bolt.
Supportengine
and
drive out bolt cautiously. Remove distance piece left
and
bolt bushing
(in
case
of
solo machines) from frame eye right
and
slide them on bolt.
Tilt
engine cautiously forward,
lift
it on clutch.side
and
remove carefully from frame.
When removing engine,
care
must
be taken
that
centrifugal governor
of
ignitionmagneto
does not streak anywhere.
Disassembly
and
Reassembly Group
..
Reassembly
R&-installing the engine:
Lift
engine, without protective
cap
and
dynamo, clutch side raised, from left into theframe.
Take
care
that
centrifugal governor
of
ignition does not streak.
Run
engine front bolt through from right after bushing (solo machines)
is
inserted
in
frame
eye,
and
fit
distance piece between engine crankcase
and
frame.
Push
or
drive engine
rearboltfrom
leftthroughframe, distance piece
and
enginecrankcase.
Replace engine
top
bolt
and
tighten.
Install properly cleaned dynamo armature on likewise cleaned
tapered
end
of
crankshaft
and
secure with clamp screw.
Position dynamo body,carbonswithdrawn
and
jammed,pole pieces properlycleaned,upon
armature on timing
gear
case cover.
Run
main motorcycle wiring through engine crankcase,connect blue
cable
wire to terminal
post 61, red wire to terminal post
51
and
black wire to terminal post 30
or
both wires to
double terminal post
30/51
on
dynamo, green-red wire to terminal post 2 on ignition
coil
and
brown ground wire to ground terminal post on
dynamo
(in
case
such
post
is
not
designed, to right clamp screw
of
dynamo).
Fit
springs
on
carbon
ends.
Replace protective
cap
on
timing
gear
case cover
and
secure with 2 slotted nuts.
Position top cover upon engine crankcase
and
tighten by means
of
knurled nut.
Insert slide
in
carburettor
and
tight~n
cap
nut. Make sure rubber seal ring
in
spigot nut
and
splash
cap
on Bowden
cable
terminal
are
fitted properly.
Reconnect the fuel supply line to the petrol tap.
Reassembly
of
Transmission:
Lift
transmission assembly with clutch thrust rod from left into the frame
and
fit
it
lightly
on
clamp screws.
Be
sure that cork gasket for air channel on partition facing
is
inserted.
Install clutch thrust rod with the help
of
pliers
in
square passage
of
pressure plate, then
secure definitely
gear
box housing to crankcase rotating simultaneously transmission
in
top
gear
by means
of
shock absorber flange so that key-ways
of
drive shaft
and
clutch
plate
engage
each other.
Tighten transmission unit with screw
and
three nuts including washers.
Position
air
filter, cork gasket
cmd
tighten with handle screw.
Insertspeedometerdrive take-offassembly,securewith clampscrew
and
placeterminal cap.
Run
cable for neutral indicator
in
cover, tighten with screw bolt
and
seal the passage for
terminal post by means
of
rubber plug.
Disassembly
and
Reassembly Group
5
'.
Insertcompression spring betweencrankcase
and
clutch~elease
lever
and
attach clutch
c~ble
on
lever.
,",
Hook brake lever spring
in
bolt
on
gear
box
b0t:t0m
right.
Fasten center stand spring on stand as well
as
on the bolt
of
gear
box
botta~
left.,
Adjust kickstarter stop to correct position
and
clamp same
on
frame.
Assemble exhaust pipes including traverse tube and run down coupling
nut$
a finger tight
on
the graphite grease-coated threads
of
cylinder
head
pipe connections. The graphite
grease paste must have been mixed with water. '
Position long foot rest
on
right side
and
short foot rest oli left side on engine rear bolt,
attach exhaust pipe clips, place
lock
washer including nut
on
bolt
and
tighten foot rests
after adjustment. .
Secure nut of engine front fixing bolt.
Tighten coupling nuts of exhaust pipes with the help of hook
spanner
Matra No. 338/1.
Assembly
of
Rear Wheel Drive:
Position lower spring covering together with eventual distance washer
on
housing cover
and
take care to screw-in the rear spring, so that
its
end
is
seated
at
the bore on the
lower spring covering. '
Select a distance washer of such a thickness that the spring end protrudes through the
bore
on
covering, thus being accessible for latter removal of spring.
Screw
upper
spring retainer on
rear
spring
and
place upper spring covering.
Assemble bottom covering on lower end
of
springing mechanism, together with rubber
buffer
and
washers
as
needed for proper accomodation
of
the covering.
Treat rubber coupling of shock absorber with talcum powder to facilitate the entering
of
flange pegs.
No
oil
or
grease must
be
used.
Set the complete
rear
wheel drive unit from inside frame respectively shock absorber
flange
and
insert.
Insert upper spring retainer
in
frame eye
and
drive the greased guiding tube, the recess
for the lower clamp screw
at
backside, from top downwards.
Place lower clamp screw, hook silencer butt-strap
on
screw
and
tighten clamp screw.
On
R
51/3
of 1952
and
R
67/2
models, secure upper spring retainer
and
spring covering
by means
of
cap
nut, then tighten upper clamp screw.
Assembling left Hub Spindle Holder:
Assemble spring, coverings, rubber buffer as
done
on,
rear wheel drive housing cover,
and
install the springing mechanism on frame.
OnR
51/3
of1952
and
R67/2
models, secure upper spring retainer
and
spring covering by
means of
cap
nut, then tighten upper clamp screw.
.
Installing Rear Wheel
and
Clamping
Upper
Spring Retainer:
After
rear
wheel
is
assembled charge the motorcycle until the upper coverings of springs
left
and
right abut. Then only tighten the
upper
clamp screws
on
the springing assemblies
(is
ceased
on
R
51/3
of 1952
and
R
67/2).
·Disassembly
and
Reassembly Group
6
Engine Group
Technical
Data
Model R51/3. R51/3
R67
R67/2
Year
~f
construction
1951
1952
1951
1952
Engine numbers starting with
522
001
526
210
.
610
001
612
001
.
Number
of
cylinders 2 2
Cylinder
arrangement
opposed
type
opposed
type
. Bore
68
mm
72
mm
Stroke
68
mm
73
mm
Capacity
.
490
c.
c.
590
c.
c.
Compression ratio
6.3
: 1
5.6
: 1
6.5
: 1
Continuous
power
24
h.
p.
26
h. p.
28
h.
p.
5,800
r.
p.
m.
5,500
r.
p.
m.
5,600
r.
p.
m.
Valve timing of R51/3, R
67
and R
67/2
(measured
at
2
mm
= intake valve
opens
after
top
dead
centre
.79" valve clearance) intake
valve
doses
after bottom
dead
centre
30°-35°
exhaustvalve
opens
before bottom
dead
centre
31
0 -
35
0
exhaust valve closes
before
top
dead
centre
5°
-10°
operating
valve
clearance
intake
0.15
mm
=
.006/1
{measured
on
cold engine} exhaust
0.20
mm
.008"
Carburettor:
2 inclined carburettors,
air
fed
from joint
air
filter with
starter slide
Model R51/3 R
5113
(1952)
R67
R67/2
Type
of
air
filter Knecht Eberspocher Knecht Ebe,rspocher
left
carburettor
Bing
1122/41
1/22/61
1/24115
1/24/25
right
carburettor
Bing
1/22/42 1/22/62
1124116
1/24/26
carburettor
passage
22
mm
24
mm
main jet
"solo"
100 105
100*)
110
"
II
"side-car"
100
105
.
105
110·
idling jet
40
40
needle jet
1208 1208
J
mixing
chamber
cap
5 5
jet
needle
standard
No.2
needle <;ldjustment 3
idling
air
screw 1- 2 turns
opened
1 - 2 turns
opened
weight
of
float mechanism
7g
7g
*) For solo sports riding
of
R
67
a main jet
105
can be used.
This
results by lying position of the rider
in
. a higher terminal velocity with moderate increase
of
consumpfion
at
top
speed.
Engine
Group
1
Ignition:
Magneto
ignition
max.
spark
advance
spark
retard
gap
of
contact
breaker
spark
plugs
spark
plug-electrode
gap
dynamo
clutch
fuel
lubricant
and
filling quantities
R
51/3
Noris
MZ
ad/R
390 + 2°
before
top
dead
centre
90 + 1°
before
top
dead
centre
0.4 + 0.05
mm
Bosch
W 240 T 1
0.6mm
Noris 6 volts L45/60 L
R67
Noris
MZ
ad/R
360 + 1°
before
top
dead
centre
60 + 1°
before
top
dead
centre
0.4 + 0.05
mm
Bosch
W 240 T1
0.6
mm
Noris 6 volts L45/60 L
single disc dry clutch
gasoline
of
at
least 70
octane
see
lubricating
plan
Fuel Consumption
Miles
per
Imp.
gallon
approx.
Speed
in
Miles
per
hour
Solo
R51/3
I with Side
Car
I Solo
------~
R67/2
I with Side
Car
30 109
81
97 83
40
91
56.5 88.5 66
50 74.5 42 76.5 49
60 60 32 61.5 36.5
70
47 47
Engine Group
2
Fits
and
Tolerances
Cylinder:
bore
of
ground cylinder
normal
next oversize
2nd next oversize·
tolerances on ground
cylinder bores
piston clearance
in
cylinder bore:
solo motorcycles (max.
smoothness)
sidecarmotorcycles machines
for public authorities
and
competitions (max. running-in
and
operating·safety)
permissible total
wear
of
cylinder bore
and
piston
Piston:
Piston ring
gap
clearance
piston ring side clearance:
at
1st compression ring
at
2nd
and
3rd compression
ring
at
oil
scraper
piston rings
Valves:
valve stem dia.
valve
head
dia.
permissible runout on valve
head
thickness
of
valve head brim
R
51/3
68.00
mm
dia.
68.50
mm
dia.
69.00
mm
dia.
0.03
mm
max.
out of round
R51/3
0.05 -0.06
mm
.002 -.0027"
0.06 -0.07
mm
.0024 -.0028 "
R
67
and
R67/2
72.00
mm
dia.
72.50
mm
dia.
73.00
mm~ia.
conicity (top diameter shorter)
0.01
mm
max.
R
67
and
R67/2
0.06 -0.07 mm/
.0024-.0028
/I
0.07 -0.08
mm
=
.0028 -.0032"
0.12
mm
beyond piston assembly clearance
R
51/3
R
67
and
R67/2
0.2-0.4
mm
0.2-0.4mm
=
.008 -
.0161/
.008 -
.016/1
0.04
mm
= .0016
Ii
0.04
mm·=
.0016/1
0.03
mm
= .0012" 0.04
mm
.0016/1
0.02
mm
=
.0008/1
0.02
mm
.0008/1
intake
and
exhaust 7 :
g:~
mrn
intake
34
mm
= 1.34"r exhaust 32
mm
1.261/
0.03
mm
=
.001211
1
mm
= .04
II
minimum
angle
of
valve
seat·
,
.::.
45 degrees
outer correction angle on valve
.seat 15 degrees
width of valve
seat
2
mm
=
.08"
valve stem clearance 0.05 -0.085
mm
= .002":'.0034
II
permissible
wear
0.10
mm
=
.0041/
beyond volve clearance
press fit
of
valve guides 0.03 -0.05
mm
= .0012 -.002
1/
press fit of valve
seat
inserts
0.125-0.175
mm
=
.005-.007
11
Engine
Group
3
V~lve
springs: inside outside
assembly length 30.50
mm
==
1.211
34.50
mm
=
1.36/1
unloaded length 37.50
mm
= 1.48 " 46,00
mm
==
1.8111
wire
gage
dia. 2.80
mm
=
.12/1
3.50 mm;:;
.1411
coil outer dia. 23.80
mm
.94"
32.70
mm
.29 "
Connecting rod bearings:
crankpin dia. R
51/3
= 32 _
g:8?~
mm
0.000
mm
R67
and
R
67/2
= 36
0.016
permissible
wear
ofcrankpin 0.03
mm
.00121/
diametrical clearonce of
bearing rollers
in
roller
cage
0.05 -0.15
mm
.002 -
.006"
(important when
assembling oversize rollers)
. end play
of
rollers 0.10 -0.20
mm
= .004 -.008
1/
bearing rollers 7
mm
dia., 10
mm
length
oversize rollers .
7.01
-7.02 -7.03 -7.04 -
7.05
-:-'
7.06
min
dia.
width of roller
cage
15
mm
(.0595") 0.2mm
(.008/1)
less
thon width
of
connecting rod
fit
of
connecting rods no clearance, but must turn freely
end play
of
connecting rods 0.07 -
0.1
0
mm=
.0028 -
.0041/
play of connecting rod bushing
on piston
pin
0.01
-0.02
mm
.0004-.0008 "
Timing Mechanism:
assembly operating clearance
of
valve tappets (cam followers) 0.02 -0.04
mm
= .0008 -.0016
II
assembly backlash for new
timing gears ..
0.01
-0.02
mm
=
.0004-.0008"
Oil
Pump:
backlash of oil pump gears 0.03 -0.05
mm
=.0012 -.002
II
end play of
oil
pump
gears
0.01
-0.04
mm
= .0004 -.0016
/I
Electrical Equipment:
max. permissible runout on
commutator
of
dynamo 0.06
mm
= .0024
II
. max. permissible runout
on
commutator pin
of
magnetofor
centrifugal governor 0.03
mm
=
.0012/1
Engine Group
4
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