The levers may have been cast improperly, making them weak and prone to breaking.
The National Highway Traffic Safety Administration recently issued a recall for Yamaha's tiny sportbike, the new-generation R3, for a potentially weak brake lever. Here are the details surrounding the issue uncovered.
This recall affects 198 units of the 2019 Yamaha R3 manufactured between February 6 and March 6, 2019. On these bikes, the metal front brake levers may have been cast with porosities. Porosities are air bubbles where there should be solid metal. This makes the metal weaker and more prone to breaking under force. In other words, these levers could break under hard braking, precisely when you need them the most. This represents a safety hazard that should be addressed rapidly.
Defective levers can be identified by lot numbers "K3 9A 16" and "K4 9A 16" stamped into them. If your R3 has this lever, Yamaha will replace it free of charge. Owners of the affected models will be contacted by mail. Dealers will be notified and begin processing the recall between May 16 and 17.
If your motorcycle falls somewhere within the VIN range of MH3RH18Y0KK002243 and MH3RH18YXKK002427, have your dealer check it out regardless, just to be sure. You can also contact the Yamaha customer service at 1-800-962-7926 to have your VIN verified or reach out to the NHTSA at 1-888-327-4236. Campaign number assigned to this recall is 19V341000.
Fortunately, this recall has an easy fix: simply replacing the defective brake lever. Even if you have upgraded your brake levers to aftermarket units, it's a good idea to have your original levers checked out. A future owner of your bike may not know about the recall and put the stock lever back on, which could be bad news on the street or the track.