1. Remove The Flybar – The first step is to remove the flybar. Snap off the linkage that connects the flybar to the upper rotors, and pull the flybar out of the plastic linkage that holds it.
2. Remove the Old Weights – Using a pair of wire cutters or needle-nose pliers, remove the cylindrical weights found on the ends of the flybar. Make the cut right near the end of the flybar.
3. Add Lighter Weights – Some small beads, like those found in craft stores can be used to make new weights for the flybar. find small beads that weigh about 0.2 grams. Thread two beads onto each end of the flybar, and secure them with CA glue and heat shrink tubing. This picture shows the new flybar weights.
4. Re-Install the Modified Flybar – Put the flybar back on the helicopter.

And that’s all that there is to it! The lighter weights on the flybar reduce the RC helicopters stability slightly, but also make it more responsive to control inputs. You can also try adding a bit of weight to the nose to make the helicopter go faster.

Credit for this idea goes to the author of this rcgroups thread.