do NOT put double washers anywhere but right next to the master cylinder!!
I'm telling you, i have been there.. done that. Doubling up washers at the head of the banjo bolt moves the hole of the bolt and the channel of the brake line fitting out of alignment. You can push fluid through the restricted hole with lever pressure, but it WILL NOT return fast enough due to the smaller opening that you created by having washers in the wrong spot.
YOU WILL WARP ROTORS . I/we (i partly blame my mechanic) warped a set of $660 brembo 320mm rotors, another brembo rotor, AND a set of stock OEM yamaha rotors before we realized what had happened.
Yes, the stock banjo bolt is too long for a brembo mc, but put the EXTRA washers near the master cyl.
I see where you're going with it and I did realize putting two washers would move the channel of the banjo up a little, but didn't think it would affect anything as long as fluid would go through. Everything works as advertised, but would rather have no issues in the long run. I've only put around a couple hundred miles (if that) and 3 sessions of a trackday with the washers doubled up.
If you look at the picture the image0r posted, the center of the banjo is where majority of the length is when compared to the banjos, so it would have to be doubled up in between the banjos and on the M/C side. In order to make it work it would require 5 washers total. In this case, even if the extra threads on the end of the banjo were to be shaved off, the banjo channels wouldn't be sitting in the proper position.
Thanks for sharing your experience. I have stock rotors now, so it would be a good excuse to buy some aftermarkets ones if they did warp
I'll heed your warning and will get a proper banjo bolt down the road, but it just makes me wonder how others have doubled up or shaved the extra threads with no issues.