FIG. 1 is a side perspective view of a motorcycle with the motorcycle rocker box and cylinder head, the broken lines showing environment for illustrative purposes only and forming no part of the claimed design;

FIG. 2 is an enlarged side perspective view of the motorcycle rocker box and cylinder head, showing my new design;

FIG. 3 is a top plan view of the invention illustrated in FIG. 2;

FIG. 4 is a front elevation view of the invention shown in FIG. 2;

FIG. 5 is a right elevation view of the invention illustrated in FIG. 2;

FIG. 6 is a bottom plan view of the invention illustrated in FIG. 2;

FIG. 7 is a rear elevation view of the invention illustrated in FIG. 2;

FIG. 8 is a left elevation view of the invention illustrated in FIG. 2;

FIG. 9 is a side perspective view of a motorcycle with a second embodiment of the motorcycle rocker box and cylinder head, the broken lines showing environment for illustrative purposes only and forming no part of the claimed design.;

FIG. 10 is an enlarged side perspective view of the motorcycle rocker box and cylinder head of FIG. 9 , showing my new design;

FIG. 11 is a top plan view of the invention illustrated in FIG. 10;

FIG. 12 is a front elevation view of the invention shown in FIG. 10;

FIG. 13 is a right elevation view of the invention illustrated in FIG. 10;

FIG. 14 is a bottom plan view of the invention illustrated in FIG. 10;

FIG. 15 is a rear elevation view of the invention illustrated in FIG. 10; and,

FIG. 16 is a left elevation view of the invention illustrated in FIG. 10.