Synchronizing the Throttle Cables
Now you can synchronize the throttle cables. This is essential to the smooth running and vibration-free highway speed operation of your bike.
Both throttle cables should still be slackened with their locknuts loose. Carefully turn the throttle cable adjusters counterclockwise until most, but not all, of the slack is removed from the cables. Then finger-tighten the throttle cable lock nuts 'til they just barely seat. There must be some slack remaining in both cables.
Start the bike. Idle speed should be the same as you originally set it. Move the handlebars lock to to lock. Idle speed should not change. If idle speed or balance changes, you have too much tension on the cable(s) and must dial in some slack. If all checks out, you can now synchronize the throttle cables.
With the engine running, slowly roll the throttle on until the engine speed picks up to 2500 RPM. Hold it there and check the manometer fluid. If the fluid is moving, turn down (clockwise) the throttle cable adjuster on the low side of the fluid until it stops, then moves back toward equilibrium, while holding the RPMs at 2500.
As the fluid reaches the balance point, turn the throttle cable adjuster counterclockwise and stop the fluid movement as it reaches the balance point. Snug the cable adjuster lock nuts and recheck the balance by rolling on the throttle.
If the fluid does not move from the balance point as the revs come up, shut off the bike and tighten the lock nuts. Recheck and turn the handlebars side to side. If the fluid remains balanced, you now have perfectly synchronized carburetors.
Return and adjust the choke cables to the point where they just begin to move with the slightest bit of enrichener lever movement.
My thanks to Hugh Kenny, Airheads Beemer Club #6051, way up in Cheyenne, Wyoming. Hugh helped me get both my R65s calmed down and smoothed out. A Bing intervention, it was.
