The Motor Company says on certain Tri-Glide Ultra Classic motorcycles manufactured from July 14, 2014, through Oct. 15, 2015, the rear master cylinder may have been assembled with an incorrect piston.Harley says this piston may not provide the proper support and may allow a tear in the primary cup. If the primary cup develops a tear it will decrease the brake performance, increasing the risk of a vehicle crash, Harley says.Harley-Davidson will notify owners, and dealers will replace the rear master cylinder, free of charge. The recall began December 16, 2014. Owners may contact Harley-Davidson customer service at 414-343-4056. Harley-Davidson’s number for this recall is 0162.Owners may also contact the National Highway Traffic Safety Administration Vehicle Safety Hotline at 1-888-327-4236 (TTY 1-800-424-9153), or go to www.safercar.gov.