NRC Motorsports Engine Cover - Right Idle Gear You could spend a lot more money for other engine covers, but why would you? NRC is the worlds largest manufacturer of heavy-duty sportbike engine covers Manufactured under stringent ISO 9002 quality control standards Cast granular alloy flow follows each particular covers contour, further adding to its strength through design and increased section thickness; stronger than wrought (billet) granular alloy and less expensive Heavy-duty engine cover replacements are mandatory for all U.S. road racing organizations