With a Haynes Manual, you can do it yourself, from simple maintenance to full repairs. Every Manual is based on a complete stripdown. Our authors and technicians work out the best methods to do a job and present this with the home mechanic in mind. Our Manuals have clear instructions and hundreds of photographs that show each step. Whether you're a beginner or a competent mechanic, you can save money with Haynes., Each Manual includes:, Clear and easy to follow page layout, Full procedures written from hands-on experience, Easy-to-follow photos, Faultfinding information, How to make special tools, Colour wiring diagrams (where available).Specific Models Covered:Yamaha 4-stroke Motocross Bikes 1998-2008; Models –; WR250F 249cc 2001-2008; WR400F 399cc 1998-2000; WR426F 426cc 2000-2002; WR450F 449cc 2003-2008; YZ250F 249cc 2001-2008; YZ400F 399cc 1998-2000; YZ426F 426cc 2000-2002; YZ450F 449cc 2003-2008; Engine – Petrol: 4-stroke 249cc, 399cc, 426cc, 449cc.