Yamaha Motor USA is recalling 4,262 units of its Yamaha XC155 (SMAX) scooters from the 2015-2020 model years, as their primary sheave nut may loosen, fall off, and stall the engine.
The issue is most easily identified by an abnormal engine noise caused when the primary sheave makes contact with the case cover while riding. If the vehicle is continued to be operated in this condition, the primary sheave nut may fall off.
This was determined pursuant to quality control review by Yamaha – the testing and a review of domestic and foreign models that are substantially similar parts design.
To remedy the issue, Yamaha will notify affect SMAX owners, and Yamaha dealers will install a primary retaining nut and washer, free of charge.
The new primary sheave retaining nut and washer are now silver in color, whereas the old style was black.
The new washer dimensions have also changed: ID 12mm, OD 27mm, and thickness 2.3mm. The previous dimensions were ID 12.5mm, OD 28mm, and thickness 3mm. Additionally the torque on the primary sheave nut has been increased to 53 Nm.
Concerned Yamaha SMAX owners may contact Yamaha customer service at 1-800-962-7926. Yamaha’s number for this recall is 990145. Of note, SMAX owners are advised not to ride their scooter until the remedy has been preformed.
The recall is expected to begin April 28, 2021. As always, the NHTSA is also available at 1-888-327-4236 and safercar.gov