Honda is recalling 2015-2016 CBR300R and CB300F models because their crankshafts may have been improperly machined, potentially causing engines to stall. The recall affects 11,424 motorcycles in the U.S.
According to documents released by the National Highway Traffic Safety Administration, the faulty crankshafts may create an increased load on the connecting rod bearings on affected motorcycles. Combined with high pressure and engine speeds, the added load may cause the plating on the bearing rod retainer to wear. A worn retainer may begin to corrode in the presence of blow-by gasses. Should the connecting rod bearing retainer fail, the engine may stall be unable to restart.
Issues first popped up in January 2015, when Honda’s Thai factory received a report of a connecting rod bearing retainer failing in Thailand. A second report occurred later that month and on April 29 Honda received a third report with five occurrences, all in Thailand. Thai Honda Manufacturing (THM) began an investigation in May but was unable to determine a cause. On May 12, Honda received a fourth report involving two incidents in the U.S., both accompanied by complaints of abnormal engine noises.
After receiving a fifth report on May 25 (again from Thailand), THM sought out help from Honda’s quality department in Japan to review warranty claims. THM began inspecting new crankshaft assemblies and found the crank pin diameter on some parts were out of specification. THM implemented a tooling change to improve the consistency of the crankshaft manufacturing process.
From October 2015 to March 2016, Honda R&D in Japan tested the bearing retainer surface plating. In the following months, Honda received five more reports including three incidents in the U.S. On June 30, Honda initiated recall procedures. As of July 8, Honda has received 48 warranty claims and 41 field reports related to this issue. No injuries were reported.
Honda dealers will inspect recalled units and replace their crankshaft assemblies. The repair should take just under six hours to complete.