Valve Springs
Valve springs are the part people forget during a top-end job. They lose tension with heat cycles, and a tired spring lets the valve float at high rpm — the engine goes flat up top, and in the worst case a valve kisses the piston. If the head is coming off for valves, a cam or a piston, this is the time to replace them.
Two routes are on this page. Single replacement springs from Psychic (and the SPI-boxed Psychic equivalents) are OEM-style intake and exhaust springs sold by part number for specific Japanese dirt bike and ATV engines — match them to your model and buy per valve. The Kibblewhite and Hot Cams items are complete kits: springs plus the matching retainers, seats and keepers, built to a stated valve lift such as .445", .630", .660" or .675". A kit is the right choice whenever you are installing a higher-lift camshaft, because the stock spring may bind before the cam reaches full lift. Pick the kit whose rated lift meets or exceeds your cam's lift, and note the spring style: a beehive spring runs with a lighter retainer, and titanium kits are the lightest for high-rpm race motors. Kibblewhite's full range of application-specific kits is in Spring Kits.
Whatever you choose, replace the valve seals at the same time, recheck clearances with fresh shims, and if the valves themselves are worn, intake valves and exhaust valves are one section over in Valve Train. Free shipping on orders $50+ (Lower 48).
