2000 Yamaha YFM400FWA(M) Factory Service workshop Manual, Page 172Get this manual
PRIMARY AND SECONDARY SHEAVES
PRIMARY AND SECONDARY SHEAVES INSTALLATION 1.Install: Secondary sheave assembly V-belt Primary sheave assembly NOTE: Tightening the bolts will push the secondary sliding sheave away, causing the gap between the secondary fixed and sliding sheaves to widenInstall the V-belt so that its arrow faces the direction show in the illustration