Production gap
12 years
Last Zephyr 1100 was 2006. Z900RS launched 2018. For 12 years Kawasaki had no air-cooled-style retro four in their lineup. They watched Triumph and Yamaha take that market and eventually came back with a modern liquid-cooled bike dressed as a Zephyr.
Engine change
Air → Liquid
Every Zephyr was air-cooled. The Z900RS is liquid-cooled (with cosmetic fins to look air-cooled). The bike is an evolved Z900 streetfighter underneath, which is why it makes 111bhp from 948cc — modern engine, vintage costume.
Power gain
+18bhp
93bhp Zephyr 1100 → 111bhp Z900RS. Modest gain considering the modern liquid-cooled engine — Kawasaki tuned the Z900RS for character, not headline power, despite it sharing engine architecture with the much hotter Z900.
Weight loss
−29kg
244kg dry Zephyr 1100 → 215kg wet Z900RS. Like-for-like the modern bike is roughly 20kg lighter despite emissions kit and ABS.
Real cost change
+$0.1k
$7,695 in 1996 ≈ $15,390 today. The 2026 Z900RS is $15,524 — basically flat in real terms. Kawasaki priced the heritage premium reasonably.
What it looks like
1972 Z1
The Z900RS is styled as a 1972 Kawasaki Z1 — the original 'Z' superbike that established Kawasaki's reputation. Round tank, separate headlight, twin clocks, finned engine cover. Heritage costume on a 21st-century bike.
Cheapest way in
$4.1k
A clean Zephyr 750 from the 90s. Real air-cooled inline four, real twin shocks, real heritage. Cheaper than the Z900RS and has a proper Z lineage instead of a costume one.
