461S0400 M4 Spring Washer Stainless Steel JIS
Made in Japan.
d=ID 4.1mm +0.4
D=OD 7.6mm -0.5
Thickness 0.9mm
Max Thickness 2.1mm 
Kawasaki part number is for reference only, 
this is a Genuine JIS washer from our supplier in Japan.
Ideal replacement to the original
Equivalent to Kawasaki Part 461S0400