2021 Kawasaki ZX-10R review - refined and improved with help of six-times WSB champion Jonathan Rea

Revised chassis geometry sees the wheelbase lengthened from 1440mm to 1450mm thanks an 8mm longer swingarm (and 1mm lower pivot) and 2mm greater fork offset.

Trail is down from 107mm to 106.7mm and weight bias is shifted 0.2% to the front. Forks springs are softer (21.0N/mm from 21.5N/mm) and the shock spring stiffer (91 N/mm to 95 N/mm).

The outgoing ZX-10R liked to be loaded-up on the brakes to turn quickly, but the ’21 bike is nimbler with more feel from the front and support from the rear. Stability, braking power and Bridgestone RS11 Racing Street rubber are all superb.

Handlebars are flatter and 10mm further forward, the seat is more steeply angled, pegs are 5mm higher and screen 40mm taller.

All this adds up to a more race bike-like riding position, although the extra wind protection is useful on the road. I’m 6ft 1in and would drop the pegs back down 5mm if I owned one and preferred the old riding position.

My arms are now too straight, I can’t look up properly riding around town and have to crouch down to see out of the mirrors. On track the new ergonomics are an improvement, apart from the high pegs.

2021 Kawasaki ZX-10R ridden at the UK launch

First published 29 April, 2021 by Jon Urry

Despite Kawasaki claiming the new fairing adds 17% more downforce, unless you ride the new and old models back-to-back (or are a WSB rider) you probably won’t notice the difference.

What you will spot, however, is a result of alterations to the suspension and chassis. Kawasaki have increased the shock’s spring rate from 91N/mm to 95N/mm and reduced it on the forks from 21.5N/mm to 21N/mm, putting more weight over the front of the bike.

This gives it a better feeling from its front end when entering bends and on track you can really push its limits while the new wider bars assist with leverage. Once upright, the 8mm longer wheelbase and 2mm greater fork offset (or aero...) seems to make it slightly more stable under hard acceleration and while the Ninja still shakes its head a bit but now calms down more quickly, helped by the Öhlins electronically-controlled steering damper.

Kawasaki haven’t updated the Ninja’s brakes and when it comes to track riding, this is a bit of a shame. The RR model gets braided lines as standard and if you are a track fiend, these are needed. If, however, you generally ride more on the road, the rubber lines are perfectly acceptable.

When it comes to comfort levels, the Ninja’s riding position remains very track-focused but the bars are now wider splayed as Jonathan Rea likes a ‘motocross’ style of clip-on, which makes them a little easier on the wrists. It’s still a wrist-heavy track bike riding position and not comfortable or roomy but at least the screen is now 40mm taller, which is a genuine blessing...

We ran the Kawasaki ZX-10R as part of the MCN fleet in 2021 and Assistant Editor Ben Clarke found the riding position to be very extreme. He said:

"For track riding or even spirited A and B-road blasts the riding position's extremity makes sense but on longer trips and more sedate roads you begin to pray for the fuel light to come on so you can have a break.

"Even compared to track-focused bikes like the Ducati Panigale V4SP or BMW M1000RR, the Kawasaki feels cramped."

Now the ZX-10R’s inline four-cylinder engine meets Euro5 with power and torque remaining at 200bhp and 85ftlb.

Cylinder head porting, throttle valves and an air-cooled oil cooler are new, as is the exhaust, which sounds good for a standard system. The gearbox has lower first to third ratios, the rear sprocket is up two teeth (now 17/41) and there are now seven riding modes: Rain, Road, Sport and four custom settings.

The engine is peaky with soft power down low, but it’s but tuned for lap times and rear tyre life, so those who like power wheelies will be disappointed.

As far as rider aids go the ZX-10R has it all: KCMF (cornering ABS and traction control system), S-KTRC (traction control), KLCM (launch control), KIBS (ABS), KEBC (engine brake control), KQS (quickshifter), ESD (electronic steering damper) and KCC (cruise control) - a top shelf electronics package to rival the European competition, but with a Japanese price tag.

The cruise control makes long motorway rides less painful for wrists and the up/down quickshifter works well, even at low speed.

Traction control is good on the road but still lets the rear spin-up on track in the wet, even in Rain mode, before the electronics eventually chime in to keep everything in check. But ultimately the ZX-10R never steps out of line.

2021 Kawasaki ZX-10R ridden at the UK launch

First published 29 April, 2021 by Jon Urry

Although the majority of the motor remains unchanged for 2021, and power and torque figures are also unaltered, it is now Euro5-compliant and features a few small yet significant revisions.

Kawasaki have lowered the ratios of the first three gears as well as adding two teeth to the rear sprocket, taking it from 39 to 41 teeth. This has made the Ninja far more eager to accelerate and has certainly reduced, if not eliminated, its breathless feel at low revs.

Although it is still quite tall geared, once you get going (above 6000rpm) there is less waiting for the meat of power to arrive and the gearbox and up/down shifter are seamlessly slick.

There is a bit of a jerk when going from a closed throttle to an open one but this is a result of Euro5-fuelling and isn’t too intrusive. The power modes (Sport, Road, Rain and Rider) are now integrated with the ABS and TC systems and launch control, engine braking control, wheelie control and cruise control are standard fitment.

Ben Clarke has found the MCN fleet ZX-10R's engine a little slow to pick up at road speeds due to its revvy nature. He said:

"At low revs the ZX-10R is a pussy cat and if you short shift your way through the gears you can avoid the powerband alltogether - which can be handy filtering through traffic or making your way through a 30mph zone.

"To get the most out of the engine you have to rev it like a 600. Riding the ZX-10R to its redline with the throttle wide open is not for the faint of heart but even in first gear you are in danger of annoying the local constabulary."

"If you never intend to ride on a track, there are definitely better bikes out there to consider with more accessible power at real world speeds."

This generation of motor and chassis can be traced back to 2011 and a quick glance of our owners’ reviews section for that and the 2016 model show nothing but glowing reviews for reliability and durability.

The introduction new valve train and Euro5 tweaks is unlikely to change that and anyway, how many road riders will ever stress a 200bhp engine?

The 2021 MCN fleet Kawasaki ZX-10R never put a wheel wrong and, despite being run through a UK winter, went back to the manufacturer looking brand new.

Find out what it was like to live with the Kawasaki ZX-10R our long-term test round-up video:

The ZX-10R remains good value when you consider what you are getting in terms of technology, speed and genuine track pedigree. It’s the only one of the litre inline four Japanese sportsbikes that can genuinely boast race success on a world level.

The road bikes to beat mostly come from Europe, though, in the form of the BMW S1000RR (£17,990) and Ducati Panigale V4S (£30,565). And despite not having the racing success of the Kawasaki, the Honda CBR1000RR-R SP (£23,699) can't be ruled out as a road-going superbike either.

Riding the Kawasaki back-to-back with the BMW and the Ducati, the discomfort of the ZX-10R is brought to the fore. It does have its strengths, though.

It has more character than the S1000RR, which supremely capable but doesn't stir the soul in quite the same way as the Kwak.

And although the Ducati most certainly wins on the desirability front, it feels stiff and awkward at low speed with a hot engine and a grabby clutch. I know which I'd rather use to navigate Aldi car park or a wet garage forecourt."

Watch: The best superbikes of 2020

Restyled with improved aerodynamics at the top of the list and good looks second the ZX-10R’s new upper fairing creates 7% less drag and built-in MotoGP-inspired winglets increase downforce by 17%, to help keep the front wheel down under hard acceleration at track speeds.

The central ram air intake path has been revised and the old bike’s halogen headlights are replaced with neat new, tiny-eyed LEDs.

It now matches its superbike rivals for bells and whistles, including a full armoury of electronic rider aids, quality suspension, brakes, new cruise control and a fresh new Bluetooth-enabled multi-function colour dash and switchgear, which immediately gives the ZX-10R the more modern feel of its superbike rivals.

Ben Clarke has been riding the MCN fleet Kawasaki ZX-10R for 2021 and has found the simplicity of the bike's electronics easy to get on with. He said:

"The riding modes work really well and I actually use them, something that isn't always a given on bikes I've ridden before.

"The throttle is very sharp in Sport mode, especially from closed but you soon get used to it. I also find that the engine braking control works really well to make the bike more comfortable on the road. I'd prefer it if they were selectable on the move, though.

"You have two options; Off or Light. I use Light on the road which smooths out any surging effect you can get holding a constant speed. Then I switch it off for track riding when I want the engine braking to help me turn the bike in harder.

"The Bluetooth doesn't offer much as there's no navigation or media system like you get with a BMW, for example, which is a shame."