Yùn not sending to motorcontroller

I just finished a working project with a funduino (nano). In this code I use the USBSabertooth library, and everything works. When attaching my Yùn to the motorcontroller it won’t send any signals.
Even the smallest things won’t work:

#include <USBSabertooth.h>
USBSabertoothSerial C;
USBSabertooth ST(C, 128);
void setup() {
Serial.begin(9600);
pinMode(13, OUTPUT);
}
void loop() {
ST.motor(1,0);
ST.motor(2,0);
digitalWrite(13, LOW);
delay(1000);
ST.motor(1,1000);
ST.motor(2,1000);
digitalWrite(13, HIGH);
delay(1000);
}

This doesn’t send anything, while the funduino does. I don’t have a clue where to start looking, but it’s pretty frustrating that a real Arduino is being more difficult than a fake one.
Any advice is greatly appreciated.

How is the motor controller connected to the Yun?

Please post a link to the motor controller datasheet.

...R

Robin2: How is the motor controller connected to the Yun?

Please post a link to the motor controller datasheet.

...R

I'm using a Sabertooth 2x32, the Yùn (TX) is connected to S1 of the Sabertooth. The datasheet: http://www.robotshop.com/media/files/pdf/rb-dim-47-datasheet.pdf

I suspect the problem is that the Rx and Tx pins on the Yun are used to communicate with the Linux side.

Perhaps you could use SoftwareSerial to create a software port on two other pins.

...R