Zero Motorcycles is recalling 2014 DS, FX, S and SR models because of a manufacturing defect that could cause the motors to seize.

According to documents released by the National Highway Traffic Safety Administration, the motor’s rotor may come in contact with the stator at sustained maximum rpms. Should the spinning rotor come contact the stationary stator, the motor may seize, potentially causing the rear wheel to lock up and increasing the risk of a crash.

The problem was first reported in Australia on Feb. 25 with a 2014 Zero SR ridden aggressively on the track by an experienced rider. The incident did not result in an accident or injury to the rider. Zero immediately started an investigation the same day, reproducing the failure on a motor in an extreme durability test on a dynamometer, running the motor for a sustained time at maximum rpm and temperature.

In the ensuing days, Zero halted internal shipments and tested more motors. On March 10, Zero engineers concluded its investigation without determining the root cause for the failures. The company determined motors built before Feb. 25 may suffer from the problem and initiated recall procedures.

Zero dealers will conduct tests on recalled motors. Should a motor fail the test, Zero will replace the motor with one that had previously been tested and passed. Zero is also telling dealers and riders to keep their motors running at speeds less than 5000 rpm until they have been inspected. Zero says the 5000 rpm limit translates to the approximate claimed top speeds of the FX (71 mph), DS (82 mph), S (79 mph) and SR (85 mph).

The recall affects 94 units in the U.S. including:

  • 2014 Zero DS models produced between Jan 24, 2014 and Feb. 20, 2014
  • 2014 Zero FX models produced between Jan 14, 2014 and Jan. 27, 2014
  • 2014 Zero S models produced between Dec. 26, 2013 and Feb. 18, 2014
  • 2014 Zero SR models produced between Dec. 30, 2013 and Feb. 20, 2014

[Source: NHTSA]