This is the same manual that your local dealer uses to diagnose & service your 4 wheeler !! Factory Service Manual 350+ PAGES OF VERY USEFUL INFORMATION FOR MAINTAINING AND REPAIRING YOUR YAMAHA YFZ 450.This does not cover the newest 450r and 450x machinesHERE IS WHAT THE MANUAL COVERS General Information Maintenance Engine Removal and Installation Engine Fuel System Engine Lubrication and Cooling Engine Combustion System Transmission System Front Wheel and Steering System Rear Wheel System Fenders and Exhaust Pipe Electrical System Troubleshooting