Owners of 2003 and 2004 RX-1 models might experience a rattling or vibrating noise at certain engine RPM levels. These models were fitted with three metal exhaust shields that are not found on the 2005 models. There are two on the lower front and one at the lower rear of the exhaust system. According to Yamaha, these shields may vibrate at certain engine RPM levels and cause a rattling or buzzing sound. All three of these shields can be permanently taken off by removing the attachment rivets that hold them in place. 2005 RX-1s have the shields removed, for this reason, along with a slight weight reduction.