Yamaha Motor Corp., U.S.A. is issuing safety recall letters to registered owners of 2015-model YZF-R1 models notifying them of defects in the bike’s six-speed transmission and telling them how to get the defects rectified.

According to a letter sent to a Yamaha YZF-R1 owner and shared with Roadracingworld.com, “In affected motorcycles, both second gear wheel and pinion gears in the transmission may break as a result of extremely high stress and/or improper shifting. This is due to inadequate component strength and stress concentration at the gear teeth bottom land. In addition, the third and fourth gears may be deformed or break as a result of excessive stress caused by hard usage. This is due to inadequate component strength. If gears fail, the transmission could lock up, causing loss of control that could results in a crash with injury or death.”

The letter advises owners to contact an authorized Yamaha dealer to have the transmission replaced with a transmission of a different design, at no charge. The work may take 16 labor hours, states the letter, but the actual time a dealer keeps the motorcycle may be longer than that due to their individual service schedule.

The letter states that “you should not ride your affected motorcycle…until this modification is performed,” but the letter does not offer owners any advice or assistance on how to transport their motorcycle to a dealer.

Owners who have had this problem repaired prior to the recall notice may be eligible for reimbursement.

For more information about the recall, owners should call Yamaha Customer Relations at (800) 962-7926.

The letter also states that “If, after contacting Yamaha Customer Relations, you are still not satisfied that we have done our best to remedy the situation without charge and within a reasonable time, you may submit a written complaint to the Administrator, National Highway Traffic Safety Administration, 1200 New Jersey Avenue, SE., Washington, DC 20590; or call the Auto Safety Hotline at 1-888-327-4236 or go to http://www.safercar.gov. Refer to campaign 15V802.”

A search at www.safercar.gov for this recall by the vehicle make and model, Yamaha YZF-R1, and by the campaign number, 15V802, did not produce a recall notice related to this transmission issue. But a search of the NHTSA website did find several complaints made by YZF-R1 owners about the transmission.

A call from Roadracingworld.com to Yamaha Motor Corp., U.S.A. was not returned prior to post time.