BMW Motorcycle Operations

Bulletin Date 08/20/2000
Bulletin #: 2748
Main Group: 32
For USA Only
BMW Motorcycle Operations
Service Bulletin
R1100/850 Model Throttle Cables
Engine surges at constant speed. Difficult to adjust and balance the left and right
throttle bodies.
Differences in opening and closing of the throttle butterflies caused by friction in the
throttle cable.
1. Fit a low friction throttle cable.
2. Check the following to ensure optimum results:
Ignition timing
Spark plugs (FR 6DDC) type / condition (reference SI 2739 in Main Group 12)
Valve clearances
Correct Cat. code plug
Check throttle housing inlet manifold for air leaks
3. Synchronize the throttle butterflies as illustrated on the attached procedure.
Note: Make sure there are no obstructions in the vacuum stub pipe prior to
connecting the Synchro tool.
32 73 1 342 149
32 73 1 342 150
R 1100 RS
R 1100 RT, R, & GS
The Low friction throttle cable was introduced into series production as follows:
R 1100 RS
R 1100 GS
R 1100 R
R 850
from 0312537 onwards (06/95 prod.)
from 0381479 onwards (06/95 prod.)
from 6379238 onwards (06/95 prod.)
from 0440499 onwards (06/95 prod.)
from the start of production
The BMW Motorcycle Limited Warranty will cover the replacement of the throttle
cable for motorcycles in the affected VIN range. Authorization is not Required. File a
warranty claim, using the following information:
Please initial and route to the following before filing
Tech #1
Tech #2
Tech #3
Tech #4
Bulletin #: 2748
Defect Code
Flat Rate Number
Flat Rate Units
00 11 00 00 00
32 72 305
15 - (R 1100 RS & R)
14 - (R 1100 GS)
23 - (R1100RT)
If the repair work is performed during routine service use the following:
Defect Code
Flat Rate Number
Flat Rate Units
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00 11 00 00 00
32 72 305
06 - (R 1100 RS & R)
06 - (R 1100 GS)
06 - (R1100RT)
Install the throttle cable with large sweeping curves. Ensure the throttle position is
not affected when the handle bars are turned. We recommend you run the cable as
shown in the drawing.
Very truly yours,
BMW of North America, Inc.
Frank Stevens
Manager - Motorcycle Operations
Motorcycle Group
Daniel E. Browning
Service Technical Manager
Motorcycle Group
Bulletin #: 2748
Page 3
R 1100/850 Models Only
R1100RT & RSL - remove the left fairing
Adjust the choke cable (increased idle) to
1 mm (0.03937 in.) free play.
Please note the throttle butterfly stops
are set by the manufacturer using a
flow bench - do not adjust the stop
left throttle body
Throttle Cable: Set the throttle cable free
play to approx. 0.5mm (0.0197in.) with the
handle bars at full lock.
Note: Warm the bike on the road and use
a fan while on the lift to maintain proper
operating temperature when making any
adjustments. If the adjustments begin to
fluctuate, the normal operating
temperature has been exceeded. Take
the bike back out on the road, then readjust.
left throttle body
Connect the BMW Synchro tool: Check
the vacuum stub pipes for dirt and grime,
prior to connect up the BMW Synchro tool
88 88 6 13 0 800
The rise of the columns is not as important
as the balance of the columns at RPM.
The left and right columns should be as
close as possible at - idle, at 3000 RPM,
and at 5000 RPM.
Bulletin #: 2748
Page 4
Check the idle-air screws for control by
screwing them gently in until they stop, that
cylinder should fall off then come back on when
adjusted to the basic setting.
R1100GS, R1100R, & R850R
R1100RS, & R1100RT
2 1/4
1 1/2
If you do not have "control" of the throttle body ,
find out what is wrong and correct it. Adjust the
idle-air screws until the columns are even on
the gauge with an engine RPM of: 1000 ☞
The idle-air screws should not require much
adjustment from their basic setting
Using the BMW Synchro tool balance the right
throttle body to the left, using cable adjuster (A)
on the left throttle body, shown in the illustration
at the right.
Check the balance at idle, at 3000, and 5000
If the adjustments begin to fluctuate, the normal
operating temperature has been exceeded.
Take the bike back out on the road, then readjust.
left throttle body
Exhaust Gas Tests: All basic setting (timing,
valve adjustment, throttle cable adjustment etc.)
must be correct and the engine must be at, but
not above operating temperature.
100° C (212° F).
On motorcycle with catalytic converters and
O2 sensors, the three way Cat will reduce the
parts per million of HC, and the percentage of
CO2 to a point where they will just barely show
up on the 4-gas tester, shown in the illustration
at the right.. In this instance disregard HC and
% of CO, and simply use the CO2, O2, and Air
Fuel Ratio (AFR) if your tester has AFR.
Note: % of CO2 is the most important indicator
of combustion.
Bulletin #: 2748
On motorcycles without catalytic converters
it may be necessary to adjust the CO content of
the exhaust gas at the CO potentiometer (left
side of bike under the seat) with a medium flat
blade screw driver.
Idle speed CO content:....1.5 ⑥ 0.5 %
Models with-out Catalytic converters - as
shown in the illustration at the right.
Note: % of CO2 is the most important indicator
of combustion.
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