Kawasaki has recalled nearly 4,200 Ninja ZX-10R motorcycles in the U.S. because oil can leak onto the rear tire and cause a crash. The National Highway Traffic Safety Administration says in documents on its website that the recall affects bikes from the 2011 and 2012 model years. They were made from Sept. 1, 2010 to Feb. 15, 2012. The documents say oil can leak from the crankcase and pool. Continued use could cause the oil to spill onto the rear tire. Kawasaki says the problem hasn’t caused any crashes or injuries. The company says that dealers will seal the crankcase to stop the leak.