I had that bike new in 77................it was called a KZ400 Special.......it was a barebones bike advertised at $999.95
No tach, no chrome fenders. 2-into 1. There was an engine design flaw and they leaked oil at the head on the left side. Re-engineered next as a 440 with an external oil line to fix the problem. you could ride for ever with just a quick rag wipe and an eventual top off on oil. Bike was quick fo a 400. Rated Top speed of 102mph Ive done 110 mnph. Light frame very tossable. Nice torque could pull a slight 2nd gear wheelie if you tried. Was faster than my buddies Honda CB400F and anothers Yamaha RD400. The Yamaha ran out of steam in 3rd but ripped ahead until then. It was a 2 stroke. The biggest drawback was it came in only one color..it was a pinkish red..... more pink than red