(Optional spring-stock tires)

2003-04 Our testing of the new SP600 showed that this quad was very well calibrated "out of the crate" in stock form. Our new Dalton plain/white primary spring has only slightly higher initial load, but slightly lower finish load than the stock primary spring. Use of the plain/white primary spring keeps the engine in a better part of its power curve all the way through the shift pattern. Better bottom/mid acceleration with 1 mph gain on top end resulted. For stock tire application.