I decided to put stainless steel braided brake lines on the GPz. I've done this on lots of bikes with great results. But it's definitely a job for a professional, don't mess with your brake lines unless you really know what you are doing.
In the past I have always used Galfer lines, but I'd heard good things about Spiegler and decided to try them.
Well... it ended up being a really hard project. The lines went on fine and bleeding was the normal big project. An important last step is to squeeze the brake lever very hard for several minutes and then to check the fittings for leaks: and my banjos were leaking! I double checked the torque specs and then tried a whole bunch of things to solve the leak, including over torquing the aluminum banjo bolts that Spiegler had provided. I searched the Internet and called Spiegler twice to confer. Nothing worked. Fluid leaked at the banjo bolt crush washers at several of the connections.
I was concerned about the aluminum banjo bolts. They where really cool, but you can stretch them and break them. I thought maybe they were stretching and not putting enough pressure on the washers. So I called Spiegler and ordered stainless steel banjo bolts and a bunch of new washers.
When the new bolts and washers arrived, it was a revelation... the new washers were different! I immediately called Spiegler back, and they confirmed the difference; they had gotten a bad batch of washers and I must have gotten them with my original shipment.
This picture shows the bad and good washer, and the obviously different profile.
The thin washer is more easily crushed.I could even feel the difference when tightening the banjo bolts with the good washers. When I tightened the banjo bolts with the bad washers my torque wrench quickly "clicked" but with the good washers I could feel the washer getting squished before I reached full torque.
And of course, with the good washers there were no leaks and the job was easily completed. Too bad I first wasted many hours with the bad washers.