2000 Yamaha YFM400FWA(M) Factory Service workshop Manual, Page 146Get this manual
CAMSHAFT, ROCKER ARMS AND VALVES
VALVE AND VALVE SPRING INSTALLATION 1.Apply: Molybdenum disulfide oil (onto the valve stem and valve stem seal) 2.Install: Valve spring seats Valve stem seals New Valves Valve springs (inner and outer) Valve spring retainers NOTE: Install the valve springs with the larger pitch facing upwardsb Smaller pitch