Kawasaki's Quiet Revolution: The Rise of the Z400 & Z750

Even while Kawasaki and others were making tearaway two-strokes, environmental pressures in the biggest two-wheeler market were increasing. Spearheaded by Californian regulations, the need for quieter running engines and lower exhaust emissions prompted a move to four-stroke power.

kawasaki z400 z750

Into this arena, Kawasaki introduced two bikes a few years apart but both effectively replaced Akashi icons – big shoes to fill…
The Z400-B was one of the very first Kawasaki motorcycles built in Kawasaki's new Nebraska assembly plant which opened the same year as the 400 was launched in 1974. A humble 398cc parallel twin with two balancer shafts to reduce engine vibration, the Z400 boasted twin carbs (that were prone to imbalance and leaking) plus a combination of front disc and rear drum brake.
Marketed in the USA as an entry-level bike to beat rising fuel costs, the Z400 lasted for ten years growing eventually to 440cc and a sixth "overdrive" gear. Prone to oil leaks, it could have remained obscure, but the Hipster boom effectively flushed it out of the shadows to become a cheap donor vehicle for customization.
The same could be said for the Z750-B, another parallel twin but with double overhead cams in contrast to the SOHC Z400. Launched in 1976 (the same year the Z1B morphed into the Z900-A4), the Z750-B was good at low to middle revs but suffered from intrusive vibration at upper levels.
Replacing the legendary two-stroke, three-cylinder H2 750 was a tough ask even if the final H2C was in the lowest state of tune of any 750 “triples” and, sadly, the Z750 never really caught on. The Z400, in turn, pushed the KH400 aside in 1976 with Kawasaki eventually replacing the 400 and 750 twins with four-cylinder machines in the years to come.
A lot more Z400's were sold than 750's so prices are lower but neither (even in good condition) are that expensive. And because they were both made in reasonable numbers, you can still get a bargain. If you are honing a Hipster machine or settling for standard, CMSNL has shelves loaded with Z spares so as they said in The Rocky Horror Show – “Let’s do the Time Warp Again”.