2018 Suzuki RM-Z450

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Vital MX: This is a big year for Suzuki, after a solid ten years we finally have a new RM-Z450 to drool over. Earlier this month we actually visited Suzuki's R&D center in Japan to learn more about the new machine and chat with some of the crew involved with developing the bike. During this time, we actually found out how many parts on the works bike we rode the day before were production, with the biggest one being the whole chassis. If you want to read our thoughts on that bike to get some insight on how the new RM-Z will handle, click here - Tested: 2018 Suzuki RM-Z450 WS (Works Special) and you can check out the video just a bit farther down.

So what's new? Let's start off with the obvious; the chassis and body work. Although Suzuki actually went through three frames across the previous generation bike, this is the first one that's really looked "different", of course the new subframe and bodywork makes this standout even more. The new frame is thinner along the main spars, as we learned from riding the works bike, and the inside of the hollow frame spars no longer have a cross-member. Meaning there's a bit more flex and comfort where Suzuki wanted and also added to how the front end responds to obstacles and increased feeling, allowing the front to "follow the ground" better.

Also adding to improved front end feel is the swap from Showa's SFF TAC forks to the new 49mm twin-chamber spring fork, which debuted last year on the CRF450R. As we already found on that bike, these forks are very...very close to A-kit and are some of the most trick dampers you'll find on a production motorcycle. Although, this change does net Suzuki an added three pounds to the RM-Z. But, due to some weight loss in the frame, swingarm, subframe, fuel tank and other areas; the 2018 model is within one-tenth of a pound of the outgoing version with a reported wet weight (fuel of full and ready to ride) of 247 pounds. In the end, the bike has increased its front end weight bias slightly over the previous model, mostly due to the three pounds from the spring forks up front.

In the rear is something no other brand has taken on, as Suzuki debuts the first production version of Showa's BFRC shock (Balance Free Rear-Cushion) for a motocross application. We've talked about these shocks for a while on Vital, mostly in Pit Bits, as teams have been experimenting with them in works trim for nearly four years now. What makes them different? In simple terms, the main job of compression and rebound has been moved from the piston and shims on the shock shaft, to the very large adjuster seen at the top of the shock (the area we typically call the compression adjuster). The shock piston on the shaft has been replaced by one with no holes, so it now acts as a plunger that pushes oil into the dual pistons and shims located up top in the adjuster housing. With the oil replenishing to the bottom of the shock in a system that's similar to a twin-tube design. Overall, these shocks are supposed to be more responsive and active feeling, meaning improved traction as the tire moves more along the ground. Once again, the works bike we tested had a version of this shock, so jump over there for a bit more info on the feeling of the unit.

As for the engine, there are some changes but also carry overs from the previous model. This isn't an all new piece, as everything from the piston/cylinder area down is carried over from 2017. The updates all relate from the piston up as the engine has received a new piston, higher lift camshafts, new cylinder head, throttle body, and intake tract shape/design. Starting with the way air and fuel get into the engine, Suzuki has offset their airfilter and airboot slightly in the subframe to give it a straighter shot around the shock and into the throttle body. This means the air has to curve less as it goes into the throttle body, with better velocity and less turbulence.

As for the throttle body, the new RM-Z450 is the first of the Japanese manufacturers to adopt the under-side fuel injector design to a production bike, as they've almost all used it on their factory race bikes the past few years. So what does this do? It improves fuel sheering and atomization for a better mix into the incoming air. Allowing for a better "mix" and improved combustion once it reaches the inside the chamber. They do this by spraying the fuel upwards into the butterfly valve as it opens in the throttle body. The incoming fuel literally hits the edge of the butterfly valve, causing the droplets to breakup and disperse more efficiently along the air tract.

Once we're past the throttle body comes the new cylinder head port. The intake side has been tweaked to slightly change the intake angle and improve the flow of the fuel/air mix into the valve opening and the combustion chamber. As with the changed intake tract, it's all about minimizing turbulence/disruption and improving how it gets into the engine. Inside we have a new piston but it holds the same compression ratio as before. Also, the RM-Z has gained higher lift cams and then finally the exhaust ports have been improved before things flow out to a new exhaust system. Overall Suzuki's goal was to increase mid-to-top horsepower, mostly due to improved air/fuel flow and atomization, while also gaining a bit of torque off the bottom. They also showed on a short dyno graph and improved mid RPM range torque spread, as it doesn't drop off as quickly as the 2017 engine.

Last up on the notable list of changes is electronics. Suzuki chatted with us about their power management control, which is similar to the system used by Kawasaki in their 450 and the GET electronics. Before there is any serious confusion, this isn't a traction control system like the ones found on cars or street bikes, as those are wheel sensor based. As we've spoken about in previous articles, that style system doesn't bode well for motocross, as our front and rear tires are never really traveling the same speed, meaning that style system would be too intrusive for our bikes and the way we ride. What this system on the Suzuki does is measure throttle position, versus RPMs and gear selection. If the system senses a large spike of RPMs below a certain throttle position (so the system doesn't kick in when wide open or near wide open, in the air or in the whoops for example) it will begin to change the engine mapping to cut a small percentage of power, such as a couple percentage, until the RPMs stabilize and then roll back to the standard mapping. Beyond this, the new RM-Z450 also features updated two mode launch control. For a very clean explanation on how these two modes work, here's the exert from the Suzuki press release found farther down.

• A-Mode: For hard surfaces or slippery conditions at the starting gate. In this mode, S-HAC alters ignition timing at the moment of launch and the ride over the gate to reduce wheel slip to deliver a smooth take off. It also advances ignition timing during this sequence for stronger acceleration. After 1.2 seconds or when you reach third gear, the system shuts off and returns to normal ignition timing.
• Benefit of A-Mode: For novice riders, and/or hard and slippery traction conditions, use A-Mode for a more controlled launch.
• B-Mode: When conditions at the starting gate have better traction, and a more aggressive launch is desired. S-HAC will advance the ignition timing to allow increased throttle response and stronger acceleration off the line. The ignition timing alternation is in a similar sequence as A-Mode, but with increased overall timing. One of three conditions will return the ignition to normal operation (whichever happens first): After 4.5 seconds has passed since throttle opening, or when you shift to 4th gear, or when the throttle is closed.
• Benefit of B-Mode: For skilled riders, and/or good starting conditions, use B-Mode for a more aggressive launch.
• Base Mode: Standard power launch, no action required on the S-HAC switch.

So what can we take away from all this? Well, based on our experience on the works bike (video right below) the new chassis is better balanced in the handling department. Keeping Suzuki's traditional tight turning prowess, but adding a bit of stability and long, flowing corner strengths. Weight has been added with user requested forks (springs!) but they've managed to shave off enough to keep things even with the 2017 model. Gone is the aluminum fuel tank, but it's claimed weight puts it right about where the 2018 Honda CRF450R and Yamaha YZ450Fs will be. Beyond that, the new suspension components should add increased rider comfort, with the new shock being a piece that should really suit the "average-joe" with its intended performance. Now the engine is the question mark as the bike we rode had modifications beyond the 2018 stock engine, but the data shown to us points towards improvements in vital areas. In the end, it's not the most drastic overhaul of a bike, maybe even a little cautious...but they targeted each place the previous model was lacking and improved them without going overboard on design changes. Something that really drew people to the previous model was the lack of transition or learning period it takes to ride a current RM-Z450 and from our first experience aboard the WS model, that same thing can be said about the 2018 version.

For the exact parts and specs changes, plus a bunch of cool cut-away shots, check out the official press release from Suzuki below.

Suzuki Press Release Below:

Key New Advancements

• Increased Engine Performance
• Improved Throttle Response with Higher Peak Power
• Evolved Traction Management System Helps the Bike Hook Up Updated Suzuki Holeshot Assist Control (S-HAC) Gets You Out Front
• Advanced Cornering Performance
• New Frame and Swingarm are Lighter with Excellent Strength
• Re ned Chassis Dimensions Blend Nimble Handling with Stability Improved Coil-spring Fork Provides Great Performance and Easy Tuning New Showa BFRC Rear Shock Delivers Remarkable Damping Response Bridgestone X30 Tires bring Outstanding Grip
• Improved Braking Performance
• Larger Front Brake Increases Stopping Power and Feel
• New, Compact Rear Master Cylinder is out of the Way of Mud and Boots
• Functional Styling
• Aggressive New Styling Blends Function with Suzuki Character
• Narrow Cockpit Lets Rider Move with Ease for Maximum Racing Performance

Overview

Developed using Suzuki’s RUN, TURN, and STOP philosophy that creates a Winning Balance between engine and chassis performance, the 2018 RM-Z450 has stronger brakes for better stopping power, a wider spread of engine muscle with higher peak power, and a frame that is stronger and lighter resulting in a nimble chassis that elevates the standard for cornering performance.

Engine Features

New 449cc liquid-cooled 4-stroke, 4-valve DOHC engine is the latest incarnation of Suzuki’s proven and reliable, fuel-injected powerplant.

The engine has higher peak horsepower with more torque at lower engine speeds for improved throttle response through the entire rev-range.

The cylinder head intake port shape is changed to tumble flow the fuel/air mixture by 25% to help increase power output.

A 30% larger air cleaner opening is combined with a more direct air cleaner outlet tube path to the throttle body to increase air flow.

Advanced fuel-injection system makes for extra-smooth power delivery, high fuel efficiency, and superb reliability.

The RM-Z450 has a new, Suzuki-unique throttle body design with a relocated fuel injector fed by a new, higher-pressure fuel pump directly sprays fuel at the butterfly valve to improve atomization of the fuel/air charge.

The new throttle body design eliminates complex control linkage so the rider feels a more direct connection to the engine.

The intake camshaft profile is changed, including more valve lift that the prior model, increasing power at all engine speeds.

The compact aluminum cylinder is finished with Suzuki Composite Electro chemical Material (SCEM) coating for durability, light weight and efficient heat transfer.

The piston’s casting is ungraded to include strengthening ribs near the wrist pin bosses to match component reliability to the higher horsepower.

Engine starting is simple and efficient due to a long kickstarter lever, refined internal gears, larger air cleaner and breather system, plus an automatic decompression system that works precisely and efficiently (eliminating the need for a heavy and costly electric start system).

The high-flow exhaust system complies with AMA sound regulations.

New engine protectors help guard the coolant pump (on the right) and the stator cover (on the left) from debris and stones.

Advanced Electronics Features

The 2018 RM-Z450 features an evolved and faster traction management system. The Electronic Control Module (ECM) continually measures throttle opening, engine speed and gear position and then adjusts the ignition timing and fuel injector duration to fine-tune the engine output to deliver the best traction for the riding conditions.

The RM-Z450’s traction management system is different from a street-bike traction control system as it does not measure rear tire spin. Because the needs of a motocrosser are different than a street bike, this system offers constant adjustment that maximizes traction at all times.

The Suzuki Holeshot Assist Control (S-HAC) is a selectable launch system derived from the factory race bike to help riders’ takeoff from the starting gate for an early lead. There are three modes riders can choose for the best option per their skill level and starting conditions. There are three stages to the A- and B-Modes of the S-HAC system. This helps riders at the moment of launch, when crossing the gate, and through acceleration up to the full-speed. The S-HAC settings for A-Mode on the 2018 RM-Z450 are updated to aid the rider’s throttle control during launches.

• A-Mode: For hard surfaces or slippery conditions at the starting gate. In this mode, S-HAC alters ignition timing at the moment of launch and the ride over the gate to reduce wheel slip to deliver a smooth take off. It also advances ignition timing during this sequence for stronger acceleration. After 1.2 seconds or when you reach third gear, the system shuts off and returns to normal ignition timing.
• Benefit of A-Mode: For novice riders, and/or hard and slippery traction conditions, use A-Mode for a more controlled launch.
• B-Mode: When conditions at the starting gate have better traction, and a more aggressive launch is desired. S-HAC will advance the ignition timing to allow increased throttle response and stronger acceleration off the line. The ignition timing alternation is in a similar sequence as A-Mode, but with increased overall timing. One of three conditions will return the ignition to normal operation (whichever happens first): After 4.5 seconds has passed since throttle opening, or when you shift to 4th gear, or when the throttle is closed.
• Benefit of B-Mode: For skilled riders, and/or good starting conditions, use B-Mode for a more aggressive launch.
• Base Mode: Standard power launch, no action required on the S-HAC switch.

Designed for motocross-use, the lightweight, battery-less, electronic fuel injection system is key to the engine delivering efficient power.

Easy-to-use Fuel Couplers are included to simplify EFI tuning

For quick fuel adjustments to suit riding conditions, two couplers are provided. One is for rich and another for lean fuel setting compared to stock setting. Riders can change fuel settings in seconds by simply connecting either coupler to the wire harness.

Transmission & Drive Features

Redefined 5-speed transmission enables precise gear shift operation. The transmission feel has been improved with a precisely machined shift cam for accurate gear selection. Specialized machining processes also increase the precision of the matching gears.

The multi-plate, wet-clutch uses rack & pinion clutch release mechanism for precise feel of the engagement and disengagement points while riding.

The new, lighter-weight chain guide is shaped to accurately route the drive chain smoothly.

Chassis Features

The 2018 RM-Z450 features a new frame and swingarm design that continues the Suzuki’s reputation as the best handling motocrossers available.

The new aluminum-alloy twin-spar frame combines cast and extruded sections to achieve superior front-and-rear weight distribution while balancing strength and weight.

The new frame is 700 grams (1.32 lbs.) lighter to improve cornering performance and shock absorption while delivering stable handling.

The new swingarm is assembled with thinner materials for 100 grams (0.25 lbs.) lower weight while cornering performance and handling stability is improved.

The wheelbase is shorter and the frame head pipe is relocated to produce quick and nimble handling characteristics.

New hexagonal aluminum rails are used on the sub-frame for lighter weight, a slimmer appearance and easier air-filter service.

The sub-frame rails are moved inward to slim the bodywork, but are also raised to provide additional space for the larger air cleaner and the advanced BFRC shock absorber.

Not only is the sub-frame thinner, but the all of the body work is slim to enable the RM-Z450 rider to move freely in the cockpit, especially during spirited riding.

Inspired by the advanced suspension from the GSX-R1000R Superbike, the RM-Z450 has a new SHOWA Balance Free Rear Cushion (BFRC) shock absorber.

The BFRC uses a separate, external damping circuit that improves the responsiveness of damping force to deliver excellent traction and better absorption over bumps.

The fully adjustable BFRC controls damping so well during minute suspension movements that ride comfort is increased at lower speeds while stability is enhanced at higher speeds.

New generation, improved SHOWA coil spring front fork has larger inner tubes and rod pipes for strength and durability. Front suspension tuning and maintenance is balanced and easy; a great bene t during frequent riding.

Springs in each fork leg combine with larger, adjustable damping cylinders to deliver better response to the terrain and provide a strong feeling of control to the rider.

The strong, RENTHAL aluminum tapered handlebar have a straighter bend that prior models to help aid the rider during aggressive maneuvering.

A new, lighter upper fork bracket is used to complement the new front suspension and handlebars.

To improve stopping performance and feel, a larger 270mm wave-style front brake rotor is used.

A new design rear brake master cylinder hugs the frame beam to reduce dirt contamination and the chance of the rider’s boot touching it during riding.

To support the additional engine, braking and handling performance of the 2018 RM-Z450, the tires are updated to the race-track developed Bridgestone Battlecross X30 tires.

The wheels feature black-anodized rims with a new cross-section design that maintains strength while reducing un-sprung weight.

Suzuki MXGP-inspired styling has a sharper front fender and radiator shrouds blending into side covers and an upswept tail to promote the impression of speed while reducing weight and easing service.

The functional styling and the motorcycle’s trim chassis permits a variety of rider positions that facilitate control and comfort.

A new plastic fuel tank weighs half-a-pound less than the prior model’s aluminum tank. Fuel capacity is raised to 1.7 US gallons.

The seat base, inner fenders and side covers were developed to reduce moisture and dirt from getting to the air cleaner. This helps prevent debris from contaminating the air fiter element.

The new seat is slimmer, with revised foam density to aid the rider’s control of the motorcycle. The seat weighs half-a-pound less than the prior model and has a large, blue gripper panel that runs nose-to-tail on the cover.

The Suzuki Championship Yellow bodywork is enhanced with distinctive blue and black striping and modern logo graphics.

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