Originally Posted by Racecrafter

OK, for all of you "DownGraders" and "keyboard cowboys" who like to pick on the uninformed...

The XZ 28 is not called a v-spec. OK? We cleared that up.

The XZ shares the same bearings as the VZB 21 "v-spec" and has the 21J carburetor before it was introduced on the Speed tuned VZB 21.

All other aspects of this engine are different.

The XZ28 is "Over Square" in that its bore is bigger than its stroke (1.2mm) where the VZB21 is barely over square by half of that (.6mm)

The XZ28 is a 5 port engine where the VZB21 is a 3 port.

The con rod on the XZ is wider and longer than the VZB.

The case design is also different. (But now found on the OS built Ninja JX .21line of engines)

Anything else?