By Pat Foster and Donn Maeda

Back in April we journeyed to the All Japan National MX Championship series opener at Kyushu Sportsland in Kumamoto, Japan, and saw what was ultimately a great preview of the 2018 Suzuki RM-Z450. Piloted by former All Japan National Champion Yohei Kojima, the factory Suzuki RM-Z450WS featured the same all-new bodywork and chassis that found its way onto the production machine that will arrive on Suzuki dealership floors in September. Today in Catawba, North Carolina, at the JGR MX team track, we got to spin our first laps aboard the exciting new 2018 Suzuki RM-Z450.

WHAT'S NEW

The new chassis is lighter and thinner. New bodywork is slim and easy to maneuver on.

The most obvious change made to the 2018 Suzuki RM-Z450 is the all-new chassis and bodywork. The new frame and swingarm were redesigned with the target of maintaining Suzuki's traditionally excellent handling and cornering characteristics. The chassis itself is thinner and features new cast an extruded aluminum frame parts, as well as new hexagonal tubing in the subframe for lighter weight and a better flex characteristic. All told, the new main frame weighs 1.32 pounds less, and the new swingarm – which has thinner construction – saves an additional quarter pound. The aluminum fuel tank of the previous model has been replaced with a plastic unit that saves weight, and the new frame is wrapped in all-new bodywork that has a refreshing new look and sleek profile.

A new Showa spring fork graces the front end of the RM-Z450. Action is far superior to that of the old Showa TAC air fork.

Showa suspension components grace the RM-Z450 and both ends are cause for excitement. The terrible Showa TAC air fork of previous model years has been replaced with a pair of all-new 49 mm Showa spring forks, and out back the RM-Z450 becomes the first production bike to be equipped with Showa's Balance Free Rear Cushion (BFRC) that has been seen on factory race bikes for a few seasons. The BFRC shock uses a separate, external damping circuit that improves the responsiveness of damping force to deliver superior traction in bumps.

The powerplant has undergone several small refinements that make some pleasant improvements.

Externally, the engine doesn't look different than previous versions, but the powerplant enjoys several key refinements for better performance. With the new chassis comes a new airbox, airbox boot and air filter. The filter opening is 30% larger and the airboot has a straighter, more-direct routing to the new 44 mm Mikuni throttle body, which has a downward facing injector needle that is powered by a higher-pressure fuel pump.  A lighter cylinder head with new intake ports, revised intake camshaft timing, a box bridge piston and new crankshaft, round out the major engine changes. Several of the transmission gears have been widened for greater durability. The S-HAC electronic starting aid has been reprogrammed to offer superior performance in both modes: hardpack/concrete, or tacky dirt.

Aesthetically, the new bike is stunning. From our first day on the bike, we can report that it is better than the '17 bike in every way.

Finishing touches on the machine include an oversized 270 mm front brake rotor, a new sleek rear brake master cylinder, a Renthal Fatbar, and Bridgestone X30 tires. The new blue-and-yellow color palette is complemented by hits of carbon fiber-look graphics on the radiator shrouds and side panels. The front and rear fenders are both narrow and futuristic looking.

ON THE TRACK

Suzuki flew select members of the press to the JGR MX track in North Carolina to spin our very first laps on the all-new machine. The track was ripped deep and watered well, so the course rutted up everywhere and although they were tamed down for this event, the jumps were big!The first thing

The first thing that you notice when sitting on the '18 RM-Z450 is how narrow it is. The old bike was not a porker by any means, but the new bike feels very thin between your legs and the new bodywork is smooth and easy to slide fore and aft on. Conversely, it is not so thin that it is hard to grip with your knees and boots…it's just right, just like Baby Bear's porridge. The seat is flat and is just firm enough to hold you up without feeling like a sofa like older Suzuki saddles did. To go along with the slim new feel is the typical light-feel on the track. Lets not kid ourselves – the Suzuki is still one of the heaviest bikes on the stand – but on the track and in the air it feels light, nimble, and quick handing.

Cornering is the RM-Z450's forte. Nothing can carve inside a yellow (and blue) bike.

The slim tank/radiator shroud area makes it easy to get way forward on the bike in corners, which is part of the reason that the RM-Z corners so incredibly well. Of course, an even greater front-wheel weight bias for '18 doesn't hurt; the RM-Z450 has seemingly unlimited amounts of front-end traction in the corners and the bike does it all when it comes to directional changes. Lay over in a deep rut? Yep! Sweep the fast outside line? No problem! Change direction mid-corner? Of course! Suzuki has prided itself on producing a great-cornering machine for over a decade now, and things haven't changed a bit. The bike remains pretty stable at speed in spite of its exceptional cornering traits, and the bike was all-around trustworthy in all areas of the track. The one complaint we had about the bike's overall performance today was that both ends of the suspension felt soft and would exhibit a wallowy feel in the deep, sticky, whoops on the track today. We heard that stiffer spring rates front and rear were liked by the R&D test riders, but it was too late to change the production spec.

The Suzuki flies predictably and lands comfortably. On the track, it feels much lighter than it really is.

But what about the engine? The RM-Z450 has never been the horsepower king in the 450 class and it will not be in '18, either. But that's not a bad thing! The Suzuki produces copious amounts of good, usable power throughout the rpm range, and only top-level riders might wish for more. Off the showroom floor, the bike has great roll-on power right off idle, a great hit in the middle, and plenty of top-end overrev. We did find ourselves clutching the bike in a few sections of the track in search of quicker pickup, but that was also because the track had beaucoup traction and sticky dirt throughout the day. On tracks with slippery sections or drier soil, the RM-Z will hook up well and be easy to ride with its linear – yet beefy – powerband.

FIRST IMPRESSION

It's hard to judge a book with only one day in the saddle, but that is the nature of an out-of-town bike intro at an infamiliar track. That said, however, the 2018 Suzuki RM-Z450 is very impressive and with our limited time spent aboard the blue and yellow machine, it is readily apparent that it is a big improvement over the bike it is replacing. Stay tuned for more testing feedback in the coming weeks.

The muffler is massive, but it is a key component in the Suzuki's friendly and fast powerband.

Specifications Engine 449cc, 4-stroke, liquid-cooled, single cylinder, DOHC Bore Stroke 96.0 x 62.1 mm (3.78 x 2.4 in) Compression Ratio 12.5:1 Fuel System Fuel Injection, 44 mm throttle body Starter Primary kick-start with automatic decompressor Lubrication Semi-dry sump

DRIVE TRAIN

Transmission 5-speed constant mesh Clutch Wet multi-plate Final Drive Chain, DID 520DMA2K, 114 links

CHASSIS

Suspension Front Inverted telescopic, coil spring, oil damped, adjustable damping force Suspension Rear BFRC – link type, coil spring, oil damped, adjustable spring preload & damping force Brakes Front Disc brake, single rotor Brakes Rear Disc brake, single rotor Tires Front 80/100-21 M/C 51M, tube type Tires Rear 110/90-19 M/C 62M, tube type Fuel Tank Capacity 6.3 L (1.6 US gallons) Color Championship Yellow with black/blue accents

ELECTRICAL

Ignition Electronic Ignition (CDI) Spark Plug NGK DIMR8C10

DIMENSIONS

Overall Length 2175 mm (85.6 in.) Overall Width 835 mm (32.9 in.) Overall Height 1260 mm (49.6 in.) Wheelbase 1480 mm (58.3 in.) Ground Clearance 330 mm (13.0 in.) Seat Height 960 mm (37.8 in.)

Curb Weight 112 kg (247 lbs.)