I have a 2014 with antilock brakes. I had the same problem. The rear brake lever went all the way down. Bleeding the rear brake took care of it for 1,000 miles then it happened again after ridding for three hours. I also used high temp material to insulate the master cylinder and lines close to the exhaust. The problem did not go away. I also purchased a more expensive bleeder. I used it numerous times and also did the manual bleed. All seems to work on my last ride of three hours. Further, the manual says air may be in the antilock system so a purge may be required. I've not tried it yet but I heard through our R3 owners experts that the Android TuneECU program will allow you to purge the system without taking the bike to the stealers. I think, I've gotton all the air out of my system. But, time will tell. Good luck! Oh, my wife says I'm full of air. I hope she doesn't try to bleed me....