In his book, The Kawasaki Story, Ian Falloon writes:
Continuing the retro theme of the Zephyr 1100 primarily for the Japanese market were the ZRX 1100 /ZR 1100 C) and ZRX 1100-II (ZR 1100 D) for 1997. These were deliberately styled to copy the Lawson Replica KZ 1000 R, but rather than being based on the aircooled Zephyr 1100 they werepowered by an engine developed from the liquid-cooled 16-valve GPZ 1100. Development saw cylinder head finning to give a classic look, a 10:1 compression ratio,and a reduction in power to 106 hp. There was now a five-speed gearbox and the frame featured a braced aluminium swingarm. The suspension too was retro, with conventional 43 mm forks and twin piggyback shock absorbers. There was a small handlebar fairing on the C (the D being naked) and the front 310 mm disks were gripped by six-piston Toxico calipers. With a dry weight of 223 kg (491.2 lb), the ZXR 1100 provided more sporting performance than the Zephyr and for 1999 received Lawson Replica colours and K-TRIC linking the throttle position with the ignition.

From The Kawasaki Story by Ian Falloon, Haynes, ISBN 1-85960-613-X