Oil could leak on to the rear tire from an incorrectly torqued fitting.
On October 15, 2018, Yamaha issued a recall on all of its tiny, mighty SR400 singles built between April 1, 2014, and July 31, 2018. The recall concerns an oil line that was improperly tightened at the factory that could cause a potentially dangerous oil leak.
According to a document filed with the National Highway Traffic Safety Administration (NHTSA), the recall, "involves the inspection of the flare nut on engine oil hose #2. If the unit is new and/or no oil leakage is visible, dealers will be instructed to properly retorque the flare nut to the new specified tightening torque of 50 Newton-meters (about 37 foot-pounds). If during the inspection process oil leakage is found, dealers will be instructed to remove the flare nut and engine oil line #2 and replace with a new assembly and tighten to the new tightening torque of 50NM. Engine oil could leak, increasing the risk that oil could get on the rear tire".
Yamaha estimates that 1,902 motorcycles are affected by the recall, but the company is still working to determine the exact VIN range so that number is subject to change once the final technical bulletin is issued. Once everything is squared away on Yamaha's end—October 29, 2018, is the current expected date—the company will issue alerts to dealerships and will send letters to SR400 owners with the details of the recall.
Thankfully, this one is a simple fix. Owners will be asked to bring their bikes into their friendly neighborhood Yamaha dealer for a full inspection. If there's no oil leak, a tech will simply tighten the flare nut to the new and correct torque rating. If there is any oil leakage, the entire oil line will be replaced and tightened correctly free of charge.
If you're an SR400 owner and you want more info on the recall before the letters go out, you can call Yamaha customer service at 1-800-962-7926 or check out the NHTSA website at www.safecar.gov.