Advanced Ignition Timing - BMW R850 Maintenance Manual

Start and warm up the engine to get 5 bars on the RID oil temperature if so
equipped. Idle will be rough due to the need to synchronize left to right throttle
bodies. Use a big rear-facing fan from the front of the bike to control cooling, if
required.
7. After warm up, LEAVE THE LEFT STOP SCREW ALONE! (The one used to
set .370- .400 volts). Adjust the right throttle body stop screw to get perfectly
equal mercury in both columns or electronic indication.
8. Adjust the right throttle body cable for equal mercury readings at just off idle,
around 1500 RPM. Use the throttle to increase RPM, not the "choke" start lever
when synching.
9. Finally, adjust both brass bypass screws individually or together in conjunction
with the manometer to yield a proper idle speed of 1000-1100 rpm and equal
mercury or vacuum readings. Closing the bypass screws will decrease RPM;
converse for opening them. On rare occasions where proper idle speed cannot
be set with the bypass screws, return to step 5 and incrementally increase or
decrease the stop screw voltage from the .370 - .400 setting then repeat
subsequent steps. Raising the stop screw voltage will increase idle RPM and
decreasing it will lower idle RPM.
10. Inspect your work and test ride, perhaps re-performing synch using ONLY the
bypass screws and right throttle cable to "fine tune."
Summary:
The TPS was set for zero volts at zero throttle plate opening (+.004 volts to
assure not going "low"). Then the left throttle body TPS was set using the stop
screw to .370 - .400 volts followed by an accurate synch of the right throttle body.
Results:
This is a simple procedure and it has worked on countless "Oilhead" BMWs. You
will notice good throttle response, best possible fuel consumption, little if any
surging and good top end. Properly performed, emissions are unaffected if not
improved.
Advanced Ignition Timing - Rob Lentini
Most manufacturers set the ignition timing for the typical vehicle with poor fuel
quality in mind. Modest performance gains may be achieved by REASONABLE
increases in initial advance. Just like my K75S, the R1100 is no exception.
Assuming you are NOT experiencing ANY pinging or detonation, you can easily
advance the ignition timing by about 3 degrees. Here's how to do it:
- Remove the small rubber timing hole cover on the clutch bellhousing (just inside
the right throttle body).
- Remove the black cover on the front of the engine. This covers the alternator
drive pulleys/belt.
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