looks like its a 77 kz900-A5. You can look it up by the vin number yourself at zedder.com. Go under bike info then scroll down to desired cc range and start reading the engine vin number ranges.
1980 kz1000B4 LTD- 1327cc 9-1 comp
Ported J model head
Psp-3x cams
RS 36s
Welded MK11 crank
Back-cut MK11 trans
MTC 2 stage lock up
Stretched 4-6 over running Hayabusa rear rim with 190 rear tire
Complete frame brace kit installed
And Much Much more- SOLD
