After several years of what has looked like an identical bike, Suzuki has given its big-bore motocross machine a thorough update. Visibly new, the 2018 RM-Z450 looks smaller overall, slimmer, with all-new more angular plastics and looks very cool indeed. In fact, I think it has got to be in the running for best-looking 450 of the year.
The new bike looks slimmer and smaller… because it is. The frame is completely new, moving the steering head back 10mm and narrows the side spars by a similar amount. The swingarm and suspension units at both ends are new, plus the engine has a host of updates.
Easy to ride fast is the key attribute of the new Suzuki engine. The power comes on smoothly with not a hint of stalling at low revs. Then it snowballs in to a strong, torquey midrange that is fast, yet tractable and manageable, before finally delivering an improved and decent top-end/over rev.
I think it’s fair to say this isn’t the fastest feeling 450 engine in a straight line… but as we all know it’s the lap times that really matter, as well as getting power to the ground – in this regard I rate the Suzuki very highly because of its ease of use.
The HAC (Holeshot Assist Control) system has been updated for an even quicker launch from the gate. Suzuki has focused on fuel and air intake improvements to achieve excellent ridability.
The fuel pump now runs at a higher psi and the underside fuel injector shoots fuel upwards, directly at the butterfly, aiding atomisation, while the cylinder head port shape is enhanced to improve tumble flow by 25 percent.
All this is aimed at improving fuel atomisation, breaking up the fuel droplets, disbursing them more thoroughly with the air, therefore leading to superior combustion. I like the engine power delivery and believe the RM-Z450 can hold its head high across a wide variety of conditions.
For many years the RM-Z’s chassis has been a favourite with riders that like to go around corners. RM-Zs have an inherent ability to hit the inside line with a planted accuracy, which fills the rider with confidence. Ruts, flat turns and any sudden loss of front wheel traction have been happily coped with on the Suzuki, and probably made it the least stressful to deal with out of all the big Japanese brands.
Fortunately the new chassis is more of the same but with an enhanced feel of lightness, a more nimble feel and a less rigid, more forgiving nature. Good job Suzuki.
Suspension is also big news on the RM-Z. The Air forks are gone, replaced by twin-chamber wire-spring Showa units that closely resemble high-end, aftermarket Showa A-kit product. At the rear Suzuki is the first manufacturer to equip a motocross bike with a Showa BFRC (Balance Free Rear Cushion) shock.
These shocks work quite differently compared with a traditional piston/shim stack set-up. On the BFRC shock the main piston is simply a plunger with no holes in it that forces oil down, then back up to the top of the shock through a twin main tube, where all the damping is controlled by the large adjustable piston/shim control valves.
This design is said to be more responsive to small bumps and with less internal friction it creates much less heat… and we all know about how shocks get hot and fade. Where I tested the Suzuki I have to say the suspension action was exceptionally plush at both ends.
The forks are fantastically supple in the initial part of the stroke and from thereon after nicely progressive. They work beautifully on little choppy bumps, awesome in whoops and take the big hits too – all in a very forgiving manner. The shock is also very plush, but on the soft side for my vast/svelte 100kg of ex-farmer body.
It has a very free feel to the stroke, particularly on rebound and definitely feels more settled when on the gas. I have to admit to liking the ‘free’ feel as it makes for a super-forgiving ride, and yet when on the power it still manages to feel very controlled.
Some riders may prefer a more solid feel from the rear but I think a little time getting used to the feel is all that’s required. Having said that, I didn’t ride the bike too much on really hard-packed terrain, so cannot be completely sure.
What I can say is that some very quick riders (Brad Groombridge and Liam Draper), rode the RM-Z with us at Taupo and were impressed by the new Suzuki. Whether this new shock design becomes a genuine step forward remains to be seen, but so far it feels like a more compliant design. It should also allow suspension tuners to do valving changes trackside much faster, as the shock itself won’t need to be fully disassembled.
The ergonomics are certainly improved by the new plastics, which also make the bike lighter and look vastly more modern. I liked the overall fit and feel of the ’18 RM-Z and found it easy to move around on with none of my gear catching on anything.
The alloy tank has been replaced by a lighter plastic one and the seat is lighter as well. The bar clamps are positioned 7mm further forward and grip excellent new-for-’18 Renthal Fatbars.
Suzuki, thankfully has finally seen fit to update the very average front brake. The old undersized disc is gone, and a new 270mm one is fitted in its place. For the rear a new slick looking master cylinder is installed. So the braking has taken a huge step forward… but frankly I’m still not overwhelmed by the power of the front – but at least it’s now average in class rather than behind.
Bridgestone Battlecross X30 tyres are fitted and while not the best tyres for our sandy test conditions, they are a decent all-rounder.
So, where are we? Well, the new Suzuki RM-Z450 is a much better machine this year, one which retains all the outstanding features of the old bike and adds to them. It still has excellent steering, a great chassis, a very racer friendly engine and very compliant suspension.
Also it looks great and thoroughly modern. But… and it’s a big but… with no electric start there is a reason to look elsewhere. However, that aside, the fact remains that the latest iteration of the RM-Z450 is a great bike and I would happily own one.
Second Opinion with Renee Johnston
It’s been a long time coming but I have to refer to the old adage ‘If it ain’t broke don’t fix it’. I would have been quite satisfied with some new (or old) spring forks and a facelift, but Suzuki has given us a lot more than that.
The previous generation RM-Z has remained largely unchanged since ’08 but, although looking dated and slightly under powered, the chassis remains unbeaten in my opinion.
Thankfully Suzuki has retained many of the chassis characteristics; the new bike turns on a dime. The new ergonomics are a massive upgrade, nice firm seat, slim between your legs and I felt the bar bend was lower than last year which is really comfortable.
Something I really noticed is the improvement in the braking department, the bigger front rotor and re-designed rear master cylinder work much better than the previous versions.
The engine is very linear and smooth, there’s plenty of torque and if you want to hold a gear a little longer, there’s a bit more over-rev allowing you to do this.
Onto the part I was most curious about… the suspension. The new Showa spring fork is surprisingly plush. I had been expecting stiff and rigid given the size of the 49mm fork tubes, but this was not the case. The front end was very forgiving yet there were no bottoming issues.
In flat turns the front stays planted and inspires confidence and the bike follows ruts easily. The rear end – my only qualm with the new bike. The shock is a bit harsh on small chop, and I couldn’t get the bike to squat and drive under acceleration.
This shock is all-new so may take some figuring out, it made the bike nervous in a couple of sections. The upside is it may have been contributing to the nice feeling in the fork.
All-in-all though, I think this is a big move in the right direction from Suzuki and a great platform for riders of all abilities.
2018 Suzuki RM-Z450 Strengths and Weaknesses
Plus – Excellent steering; engine usability; supple suspension.
Minus – No electric start; shock has a ‘different’ feel.
2018 Suzuki RM-Z450 Specification
Engine – 449.5cc, liquid-cooled, DOHC, four-stroke single
Compression ratio – 12.5:1
Bore x stroke – 96 x 62.1mm
Starting system – Kickstart
Fuel system – Fuel-injection
Clutch – Wet, multi-plate, cable operated
Transmission – Five-speed, chain drive
Frame – Aluminium twin spar
Swingarm – Aluminium
Rake/trail – 27.8°/120mm
Front suspension – Showa 49mm coil spring fork, preload, rebound and compression adjustable
Rear suspension – Showa linkage type BFRC (Balance Free Rear Cushion) monoshock, preload, rebound and hi/lo speed compression adjustable
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