If the universal joint separates, the motorcycle would stall. If the universal joint breaks, it may interfere with the swing arm and lock the rear wheel. Either condition could increase the risk of a crash.
Technical Summary: Honda (American Honda Motor Co.) is recalling certain model year 2010, 2012 and 2013 VFR1200F and VFR1200FD motorcycles. Manufacturing or assembly errors may result in the affected motorcycles having driveshaft universal joint bearings that may prematurely wear which can cause the universal joint to separate or break.