Kibblewhite heavy duty valve spring for modified XR75 engines.  Uses stock valve components.  Fits: Honda XL75 1977-1979 Honda XR75 1973-1978 Honda XL80S 1980-1985 Honda XR80 1979-1984 Honda XR80R 1985-2003Honda XL100S 1979-1985 Honda XR100 1981-1984 Honda XR100R 1985-2003 Honda CRF80F 2004-2013 Honda CRF100F 2004-2013.