2000 Yamaha YFM400FWA(M) Factory Service workshop Manual, Page 367Get this manual
FAULTY CLUTCH PERFORMANCEOVERHEATING OVER COOLINGFAULTY BRAKE POOR SPEED PERFORMANCE V-belt Oil or grease on the V-belt Primary pulley weight Faulty operation Worn primary pulley weight Primary fixed sheave Worn primary fixed sheave
TRBL SHTG
Primary sliding sheave Worn primary sliding sheave Secondary fixed sheave Worn secondary fixed sheave Secondary sliding sheave Worn secondary sliding sheave
OVERHEATING
OVERHEATING Ignition system Improper spark plug gap Improper spark plug heat range Faulty CDI unit Fuel system Improper carburetor main jet (improper setting) Improper fuel level Clogged air filter element Compression system Heavy carbon build-up Engine oil Improper oil level Improper oil viscosity Inferior oil quality Brake Brake drag Cooling system Low coolant level Clogged or damaged radiator Damaged or faulty water pump Thermostat stays closed