BMW R850 Maintenance Manual page 80

IF YOU HAVE NO COMPLAINTS WITH YOUR BIKE, LEAVE IT ALONE!
Procedure (reference BMW or Haynes manual for location of components):
1. Generously loosen the free play at the throttle cables to both left and right
throttle bodies (note '96 and newer "Oilheads" have a different throttle cable
mechanism--see manuals)
2. Unscrew the left throttle body throttle stop screw (under and inside of the
throttle body) counterclockwise (CCW) about three turns or until you can see a
gap between the end of the stop screw and the flange it pushes on to open the
throttle. You are now assured the left throttle is FULLY closed. This is important!
("Zero" throttle opening).
3. Attach the Digital Voltmeter (DVM) black lead to frame ground and the red
lead to the red/white wire going to the TPS connector located on the left cylinder
throttle body. The TPS is a black plastic 2" by 2" square module with a connector
on the bottom. Gently pulling the rubber connector boot down will expose the four
wires entering the connector to the TPS. Probing and pushing up with a paper
clip is one method of reaching the red/white wire's contacts. Put the DVM red
lead on the paper clip, turn on the ignition and engine cutoff switch, and retract
the sidestand. You should see an indication on the DVM near zero. Be SURE
you are on the DC Volts selection.
4. Loosen the two Allen head screws securing the TPS. Adjust the TPS by slowly
turning it within its slots until the observed voltage decreases to about .006 DC
volts. It will probably go no lower, which is OK. DO NOT turn it any more as the
wiper of the pot has already reached the end of electrical travel. Stop turning the
TPS just when the voltage stops decreasing and then turn it in the opposite
direction to increase the DVM by .004. Lock it down there. Going slightly up by
.004 volts will ensure your are not going "below" zero volts and this will typically
result in a "zero" value of .010 volts. Be careful of DVMs which "autorange" and
can confuse readings! ("Zero" TPS voltage .006 +.004 volts = .010)
5. With "Zero = Zero" set (zero throttle plate opening and zero voltage), turn the
left throttle body stop screw clockwise (CW) until the voltage starts to rise.
Continue turning until you reach .370 - .400 volts, the voltage the BMW analyzer
looks for the TPS at idle to cause a digital signal to "flop" or change symbology.
Lock down the stop screw with the jam nut if so equipped (early units are an
interference fit). Blip the throttle several times to check accuracy and repeatability
of the voltage to be within .370 - .400 volts. Readjust the stopscrew (not TPS
Allen screws!) if needed. Following this, reset the left throttle cable free play to
.5mm. Now you are forever done with the TPS adjustment.
6. Connect the mercury or electronic manometer to both throttle bodies. Prior to
starting the engine, use a common screwdriver to lightly close both rear-facing
brass air bypass screws on the throttle bodies, then open them to:
R1100 RS/RT: 1 1/2 turns from closed
R1100 GS/R: 2 1/4 turns from closed
R850R: 2 1/4 turns from closed
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