As you may remember from our previous coverage, things are not looking so good for Zero Motorcycles with several recalls in the past year, including faulty brake caliper mounting bolts that was issued in August, and a faulty firmware recall that caused certain models to shut down while running.
Now, after an incident with an expert rider in Australia in late February, Zero has discovered that when certain motors are pushed to their limits, the motors rotor may contact the stator, causing the engine to lock up thereby causing the rear wheel to lock up.
According to the Zero Motorcycles incident report, the mishap in Australia did not result in injury or an accident, though it became apparent that this condition was most likely to occur during sustained maximum rpm.
Zero was able to reproduce the failure on an engine dyno when a factory motor was tested at sustained maximum rpm and temperature.
As of March 10, neither Zero nor the manufacturer of the motors were able to determine what the root cause of the motor lockup was, but after their investigation concluded that certain models built before February 24th, 2014 could be affected.
As part of the remedy, Zero will be performing a stationary screening test of the motors while they are still in the motorcycle, and replacing faulty units with pre-screened ones at no cost to the owner
Although Zero is not aware of any accidents or injuries to date, they are advising dealers and owners who continue to ride their motorcycles before being screened to keep the rpm’s below 5,000.
Affected units include:
- 2014 model year Zero SR model motorcycles built 12/30, 2013 through 02/20, 2014
- 2014 model year Zero S model motorcycles built 12/26, 2013 through 02/ 18, 2014
- 2014 model year Zero DS model motorcycles built 01/24, 2014 through 02/04, 2014
- 2014 model year Zero FX model motorcycles built 01/14, 2014 through 01/27, 2014
If you own one of the following models, the recall is expected to being sometime in April and you may contact Zero at 1-888-786-9316 (1-888-RUN-ZERO), or 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.