I made a tail pipe extension for my 1150GS with Jesse bags.
I know there are a lot of threads out there on this, but I decided to do it myself after being annoyed by this:
I got 1 3/4" ID exhaust pipe and used some throttle return springs and nuts that I had.
I removed the silencer end, using 8mm socket.
Then cut the pipe so it fits under my left turn light.
Measured the springs so I know where to weld the nuts to hold the springs.
Welded the nuts using a cheap harbor freight welder I've owned for several years. Does the job, but not weld (please don't judge my welds--I know they suck, but they hold).
Here it is fitted
With my pannier back on. Need to cut the end for fit.
Used an angle grinder to sharpen the edge, so in a pinch it can be used as a weapon
Went for a ride, doesn't rattle or leak. Hopefully it will keep all (if not most) of the hot exhaust gasses off my pannier.