The tail kicks / blows out to the right when I suddenly increase the collective.

Such kick and blow outs are typically the result of low gyro gain, slow tail servo, excessive collective or tail mechanics that are unable to provide enough thrust to compensate for main rotor toque.

Try increasing the gyro gain as high as you can reach without and tail wag seen at any time during flight. A slow tail servo, stiff push-rod or faulty tail grip bearing may prevent you from reaching the optimal gain value for your helicopter. The Futaba S9650 servo has been a popular choice in past as it was the only available small size digital servo. However its intended use is for 1/12 scale cars and thus it is not an ideal match for modern high performance gyros. It is possible to increase the speed of this servo by replacing the gear train with S9257 gears.

If the helicopter has been fitted with a significantly more powerful motor than the helicopter manufacturer's recommendation and the collective range gas been increased it is possible that the tail may not be able to provide enough thrust to compensate. If enough clearance is available between the main and tail rotor, try fitting longer tail blades.

Finally, it should be noted that some ESCs with build in governor create an irregular/delayed response resulting to such tail kick on sudden collective changes. Disable the governor function and observe if the problem persists.