Softening the FCR39 Throttle Return Spring

The FCR39 throttle return spring doesn't have extremely high tension, and is likely not an issue for typical dirt bike riding. However, when you are out on a big adventure ride spanning over a number of hours, it can lead to fatigue of the wrist and forearm.

A simple fix is to relocate the anchor point of the throttle return spring which will reduce the tension on the throttle and avoid unnecessary fatigue. This is a very quick and simple modification requiring no additional parts or specialized tools.

Photo 1 of Softening the FCR39 Throttle Return Spring
This image shows the factory anchor position of the throttle return spring on the throttle actuator.
Photo 2 of Softening the FCR39 Throttle Return Spring
The first step is to flick the spring off at anchor point then lift it into position so that the spring hook can be grabbed with a set of pliers. In this image I am using an engineers metal scriber to hold the spring ready for the pliers.
Photo 3 of Softening the FCR39 Throttle Return Spring
In this image I am using a set of pliers to twist the spring hook to a 90 degree angle.
Photo 4 of Softening the FCR39 Throttle Return Spring
With the spring hook now set to a 90 degree angle, it is now hooked over the shaft actuator as shown in this image.

The final result offers far less tension on the throttle, it makes it far more comfortable when riding long distances, yet it still provides enough tension to snap the throttle back to the off position when releasing your hand. 

Author of this article: RMOTO