Please check that you are using a standard model setup on your radio.
(That is, that the endpoints are the same for yaw as for the other channels)
Also, perhaps it will work better if you remap the yaw stick to another channel (in the settings of your radio) .
From what you are describing, it sounds like there's a chance you could get it working by adjusting sliders on the trim settings screen in Freerider.
Try to pull the scale slider (for the yaw channel) until you get more movement.
After that you can use the trim slider to get the center position correct.
You can email fpvfreerider@gmail.com for further support.
(Perhaps you can make a short video that shows what happens when you go through the calibration).