In 1981 Honda introduced 'Pro-Link’ models, with rising-rate single-shock rear suspension, a 17" rear wheel and a 21" front wheel. Unusual for a four-stroke with its typical intake and exhaust valves, the 1981 and 1982 XR-500 utilized a six-petal reed valve set-up between the carburetor and the intake valves. This was intended to provide better low-end performance while still allowing a large carburetor to be used. The 1982 XR 500RC was very similar to the 1981 RB apart from decal and trim changes.