78 kz 1000 motorcycle and the engine number is different it Is z1e133000 is this a 900 or 1000 engine?

Look on the lower left front side of the cylinder as you're standing by the front tire. The cylinder is stamped with either a 900 or 1015 stamp.

900 is the 900 engine

1015 is the KZ1000 engine

Take care and good luck,

Buzz