Mine used to be black heater hose that exited through the air intake horn on the starter cover (round air filter style) and went back along the left side of the frame and was zip-tied to the left side of the swing-arm.
When I changed to the drilled hole in the airbox, I wanted the braided plastic, but could not find any the right combination of inside/outside diameters...
So I went with the non-reinforced (substandard) and it will get replaced sometime soon.

click on it!