Without a bolt, the engine will have reduced power which may result in a stall, increasing the risk of a crash.
Technical Summary: Honda is recalling certain model year 2013 CB500 (FA, F, XA, X) and CBR500 (RA, R) motorcycles. The rocker arm shaft retaining bolts may have been manufactured incorrectly resulting in the bolts loosening during engine operation. A loose bolt will initially result in a slow leak of engine oil, but if not addressed, the bolt can come out of the cylinder head entirely.