Wiseco CSK035 Clutch Spring Kit for YZ/WR400F 1998-2000

The Wiseco CSK035 Clutch Spring Kit is a direct-replacement spring kit engineered for Yamaha YZ400F and WR400F models from 1998 to 2000. Designed to restore and improve clutch performance, this kit replaces worn or fatigued OEM clutch springs with higher-quality components built to withstand the demands of off-road and motocross competition.

Key Features:

• Premium Steel Construction: Each spring is manufactured from high-grade steel for superior strength and long service life
• Shot-Peened Finish: The shot-peening process increases surface hardness and resistance to fatigue, extending spring life under repeated stress
• Heat-Treated: Heat treatment ensures consistent spring rate and dimensional stability across a wide range of operating temperatures
• Stiffer-Than-Stock Rate: Upgraded spring rate delivers more positive clutch lockup, reducing clutch slip under hard acceleration
• Direct Replacement: Drop-in fitment designed to match OEM specifications for the Yamaha YZ400F and WR400F (1998–2000)

Wiseco clutch components are trusted at every level of dirt bike competition, from weekend trail riding to professional motocross racing. Replacing worn clutch springs with the CSK035 kit is a straightforward maintenance upgrade that restores crisp, reliable clutch engagement and helps prevent costly clutch slip or chatter.