The wire reinforcement inside this tube erodes and breaks into the center of the bowden tube causing the clutch cable to catch, or even break, so you need to check this whenever you replace the cable.
Note: So what's the purpose of this "Bowden Tube" anyway; it seems to be much too long? Cable actuated or controlled systems are simple and reliable but transmit input control movement very directly to the clutch lever. The Bowden Tube gives the cable a "cushion" or allows a more linear forgiving movement between the input and reaction. In the application of the clutch control system, the use of the Bowden Tube lessens the tendency toward jerky clutch engagement. The new tube should bend around 1.5" in order for the cable to operate correctly.
.
Pacific Parts International PPI