Just found this,
Kawasaki KX400A 1975.
# 400 cc
# 2-Stroke, 1 Cylinder
# Piston Valve
# 5-Speed Return Shift
# Maximum Horsepower:
# 42 HP @7,000 rpm
# Spark Plug: NGK B9EV
# Tire Size
# Front: 3.00-21 4PR
# Rear: 4.60-18 4PR
# Color
# Fuel Tank: Lime Green, Candy Lime
# Front Fender: White or Black
# Engine No.: K5E903001-