Kawasaki ZRX1100 Bike

Kawasaki ZRX1100 Bike Overview

We call them super-nakeds now, but in the 1990s, an unfaired, conventional motorbike like the ZRX1100 was, pretty much, just called a bike. But since Kawasaki had given the ZRX a big, beefy lump of an engine, it earned itself the term ‘muscle bike’, aping the ‘muscle car’ class of American automobiles with giant engines and loads of power.

The engine is a revised variation on the ZZ-R1100 unit – meaning it powered the fastest road bike on the planet from 1990-1997. Kawasaki lopped off a chunk of peak power, and beefed up the midrange for the ZRX though, fitting smaller carbs, softer cams and lower compression ratio, as well as dropping the ZZ-R’s sixth gear.

The result was a strong, smooth 100bhp lump that made relaxed, fast progress a breeze. Hanging on at triple-figure speeds was the only problem, eased a little by the small headlight fairing. Problems are rare, but there’s a weakness in the oil supply to the number three main bearing, which can show up after high miles or extreme tuning work. The starter chain tensioner also wears, and can cause serious damage to the clutch. 

Many owners bolt on parts from the ZZ-R1100 engine, to restore some of the missing peak power and the sixth gear. OE ZZ-R cams and valve springs fit in, while aftermarket big-bore pistons, con-rods and larger carburettors can boost power by more than 50 per cent.

The original chassis had some quality touches, especially the braced tubular swingarm with eccentric chain adjusters and piggyback twin shocks. Six-piston front brake calipers do a good job when new, but they do need careful servicing to keep them at their peak. Many owners replace them with Nissin four-piston calipers, which actually work better most of the time. The stock shocks and forks will be tired by now, and quality replacements from Öhlins or WP can make a massive difference to the handling.

The ZRX’s styling harked back to an earlier breed of muscle bike – the 1980s air-cooled Z1000R, and the Eddie Lawson replica version in particular. The green/white/blue paint scheme was a copy of Eddie’s, and the small fairing, beefy tank and duck-tail seat unit all echoed that legendary superbike race machine.

The ZRX1100 was in production for four years from 1997-2001, before being replaced by an upgraded version, the ZRX1200. Now, most of the 1100s around are getting on a bit, and they don’t have the modern refinements we expect – ABS, traction or the like. But as a no-fuss, big-hearted naked roadster, with classic good looks and solid performance, it’s well worth a look.

Take a closer look at the ZXR1100 now…