YAMAHAIT 490 1983 - 1984

　　The big news in the powerplant is the bump in displacement from 465 to 487cc, accomplished simply by increasing the cylinder bore two millimeters. This follows the large, seven-millimeter increase in stroke which boosted the IT's displacement from 425 to 465cc in 1981. Aside from the trendiness involved in increasing their open-classers' engine sizes, most manufacturers are nudging 500cc because more displacement is the most straightforward route to better power.