You will need to double check but the sprocket should fit these models...
Part # = 41202-KZ4-J20
Part Description = SPROCKET (51T) - (replaces 41201-KZ4-711, 41201-KZ4-861, 41202-KZ3-B00)
Model Count = 58
CR125R-1 2001 125 CR125R Off Road
CR125R-2 2002 125 CR125R Off Road
CR125R-3 2003 125 CR125R Off Road
CR125R-5 2005 125 CR125R Off Road
CR125R-6 2006 125 CR125R Off Road
CR125R-7 2007 125 CR125R Off Road
CR125R-D 1983 125 CR125R Off Road
CR125R-E 1984 125 CR125R Off Road
CR125R-F 1985 125 CR125R Off Road
CR125R-G 1986 125 CR125R Off Road
CR125R-H 1987 125 CR125R Off Road
CR125R-J 1988 125 CR125R Off Road
CR125R-K 1989 125 CR125R Off Road
CR125R-L 1990 125 CR125R Off Road
CR125R-M 1991 125 CR125R Off Road
CR125R-N 1992 125 CR125R Off Road
CR125R-P 1993 125 CR125R Off Road
CR125R-R 1994 125 CR125R Off Road
CR125R-S 1995 125 CR125R Off Road
CR125R-T 1996 125 CR125R Off Road
CR125R-W 1998 125 CR125R Off Road
CR125R-X 1999 125 CR125R Off Road
CR125R-Y 2000 125 CR125R Off Road
CR250R-1 2001 250 CR250R Off Road
CR250R-4 2004 250 CR250R Off Road
CR250R-E 1984 250 CR250R Off Road
CR250R-F 1985 250 CR250R Off Road
CR250R-G 1986 250 CR250R Off Road
CR250R-H 1987 250 CR250R Off Road
CR250R-J 1988 250 CR250R Off Road
CR250R-K 1989 250 CR250R Off Road
CR250R-L 1990 250 CR250R Off Road
CR250R-M 1991 250 CR250R Off Road
CR250R-N 1992 250 CR250R Off Road
CR250R-P 1993 250 CR250R Off Road
CR250R-R 1994 250 CR250R Off Road
CR250R-S 1995 250 CR250R Off Road
CR250R-T 1996 250 CR250R Off Road
CR250R-V 1997 250 CR250R Off Road
CR250R-W 1998 250 CR250R Off Road
CR250R-X 1999 250 CR250R Off Road
CR250R-Y 2000 250 CR250R Off Road
CR500R-E 1984 500 CR500R Off Road
CR500R-F 1985 500 CR500R Off Road
CR500R-G 1986 500 CR500R Off Road
CR500R-H 1987 500 CR500R Off Road
CR500R-J 1988 500 CR500R Off Road
CR500R-K 1989 500 CR500R Off Road
CR500R-L 1990 500 CR500R Off Road
CR500R-M 1991 500 CR500R Off Road
CR500R-N 1992 500 CR500R Off Road
CR500R-P 1993 500 CR500R Off Road
CR500R-R 1994 500 CR500R Off Road
CR500R-S 1995 500 CR500R Off Road
CRF250R-4 2004 250 CRF250R Off Road
CRF250R-5 2005 250 CRF250R Off Road
CRF450R-2 2002 450 CRF450R Off Road
CRF450R-3 2003 450 CRF450R Off Road