What do you do when you win three championships back-to-back in two of the most competitive series in the world – American AMA Supercross and Motocross? Well, if you’re Suzuki, you continue pouring development into the bike that won them in a bid to keep the ball rolling.

That’s exactly the case with the RM-Z450 motocross bike, which wrapped up the 2009 AMA Motocross Championship with Australia’s Chad Reed before going on to capture both the 2010 AMA Supercross and Motocross titles with rookie standout Ryan Dungey.

A private test at the Frankston track in Victoria proved the ultimate playground for putting the RM-Z450 through its paces, with a slight early morning drizzle moistening the freshly graded track into a moto heaven of sorts for MotoOnline.com.au to put it through its paces.

POWER
Suzuki is using all of its factory race knowledge to improve the RM-Z package for 2011, the bike that features a 449cc, four-stroke, single-cylinder, liquid cooled, DOHC, four-valve engine.

The Japanese factory introduced Electronic Fuel Injection to its 450 in 2007, now offering two optional couplers that come with the unit for carburetion revisions.

Also revised in the engine department for 2011 is the compression ratio, which has been raised from 12.2:1 to 12.5:1, while the intake and exhaust cam timing has been changed to improve engine response.

Suzuki's RM-Z450 has enjoyed great success in recent years and has various refinements for 2011.

Adding to that are revised ECU settings, also to improve the power output for a more linear acceleration and improved over-rev.

The exhaust note is now quieter than ever as it meets the AMA race regulation of 94db.

On track, perhaps the greatest thing about the Suzuki Open class contender is its refined EFI system, not sapping any power at all and genuinely offering an arm-pulling powerband that will impress even the most experienced of pros.

While the power’s smooth, it’s definitely not compromised, giving you that true feeling of excitement that a 450 class motocrosser should provide.

The five-speed gearbox works seamlessly and the clutch action is easy enough that you can operate it throughout a moto even as you begin to tire. The on-the-fly adjuster knob is an added bonus, not that you’ll need to use it often.

Another bonus is the fact that it starts easy enough even without electric start, so one kick and nine times out of 10 it’ll fire into life.

These all amount to a top shelf contender for Suzuki, boasting one of the strongest Motocross engines in the 450 field.

HANDLING
Changes in the chassis department are revised spring rates at both ends of the Showa suspension, slightly more forgiving to go hand-in-hand with the rigid, twin-spar aluminium frame.

Other small revisions to the model include a convenient new fuel line cap for regular maintenance and updated graphics have also been adopted.

Chassis-wise, the suspension setting is still a little stiff for my 70-odd kilogram frame, however if you’re hitting the scales at around 80kg then chance are it’ll be ready to race.

Despite its stiffness, it certainly isn’t harsh, and Suzuki has got the geometry just right when it comes to steering quickly while still retaining stability – two very important ingredients when it comes to dirt bike riding.

Rail a berm or hold the gas on down long straights with rolling whoops and you’ll appreciate the handling package that the RM-Z boasts, which would probably convert nicely to more harder-packed terrains also.

Another strong point to assist in the Suzuki’s handling and comfort is its ergonomics package. They’re slim but still have plenty of places you can grip your legs to, essentially allowing riders to place their body position exactly where they require without too much bulk or weight affecting things.

The aluminium gas tank not only looks cool, but it adds to both performance and comfort on the bike.

The Renthal Fatbars come standard and they’re a good bend, even if they are slightly more suited to taller riders. Just like the RM-Z250, other ergonomic strengths include reasonably wide footpegs and the gripper seat cover.

CONCLUSION
At $11,590 the Suzuki RM-Z450 is packing a lot of excitement in its punch, proving a highly capable race bike if you’re keen to line-up on the start gates – just ask Dungey – or even a hugely enjoyable toy for a weekend wrap. The choice is yours!

A strong engine, combined with a race-proven chassis, makes for a leader in Open class Motocross bikes.

FAST FACTS
Moto Rating:
8/10 – The bike’s got one of the gruntiest motors in the 450 pack, with a refined fuel injection system and a great chassis to match.

Suited To:
Intermediate to Advanced – The power of the RM-Z is something that advanced riders will love, plus they can make the most of the supreme handling. If you’re a larger intermediate rider, you’ll appreciate the ponies in tap.

Bang For Buck:
For $11,590 you’re getting a proven championship winner, and re-sale would be pretty good at this point in time too. Suzuki is on a role right now and continues to develop the RM-Z range, making them worth every cent.

Plus Points:
+ Power on tap
+ Slim ergos
+ Proven champion

Minus Points:
– Suspension is stiff for lighter riders
– Large grips