Hot Engine And Drivetrain Procedures; Throttle Body Sync - BMW R850 Maintenance Manual

Hot Engine and Drivetrain Procedures

Throttle Body Sync

Tools
Twin Max or carb stix
screwdriver, flat blade
needle nose pliers
wrench, 10mm
house fans
Note: If you are doing this procedure for the first time, you should seat the brass
bypass screws and record the number of turns for each. Return the screws to
where you found them. Also make a note of the number of threads at some
reference point on the right throttle body cable adjuster. All this is so you can get
back to the same starting point if you mess up.
1. Engine hot at the normal operating temperature of 5 bars on the RID.
2. Bike on the centerstand, transmission in neutral.
Note: If you are experienced with this procedure, it only takes a couple of
minutes – including several double checks. If you have never done a throttle
body (TB) sync or your TB's are really out of sync, it could take much longer and
you should place 1 or 2 house fans blowing on your engine to help keep it from
overheating.
Note: You may need to slacken the throttle body cables. See
3. Turn on the Twin Max to warm up it up to help prevent drifting from the zero
calibration setting.
4. Remove the vacuum hoses from the bottom of each throttle body (TB).
5. Attach the Twin Max hoses to each TB, left hose to the left TB, right hose to
the right TB.
6. Calibrate the Twin Max by setting the sensitivity to max and then zero the
needle.
Idle Speed Adjustment and Balance
7. Start the engine.
8. Turn the Twin Max sensitivity down if the needle is fluctuating too much, but
get it back to or close to maximum sensitivity as you do the final adjustments.
9. Adjust the large brass bypass screw on each TB to get an idle speed of
~1100rpm - turn both out, counterclockwise, to increase the idle speed
(i.e. normal operating temperature)
21
Parts
none
pages 53 - 59.