Bolt from the blue
By TMX Archives on 17th Dec 09
THE all-new fuel-injected RM-Z250 has arrived with new chassis and stylish new bodywork. But its beauty is not only skin deep.
Over the past couple of years Suzuki has seen a resurgence in its on-track performances, with Ryan Dungey winning everything in the USA including the 2009 AMA West Coast Supercross Lites championship as well as the AMA outdoor series. He also won the Motocross des Nations riding the RM-Z450.
On this side of the pond the FIM MX2 World Motocross Championship witnessed its own star emerging as a potential, if not definite future world champion in the form of 15 year-old sensation Kenny Roczen of Germany, riding for the Teka Europe Suzuki squad, who in only his second ever GP rode to a magnificent second place in the second moto at the GP of Cataluña, en route to securing fifth place overall in the MX2 world championship. Not bad considering he missed the first four rounds of the season due to being under-aged at 14! He was also a two-time race winner and even won his home GP at Teutschenthal, which incredibly was only his fifth ever grand prix. In all, he stood on the podium no fewer than nine times, with two race wins, six second places and one third.
And so it would perhaps come as no surprise then that as far as their race programme Suzuki has once again come to the forefront reminiscent of days gone by - more notably the late 1970s - early '80s - when it was hard to see a championship being won by anything other than a Suzuki, and with the kind of success experienced in 2009, results that really have been long overdue, the technicians are perhaps as keen as ever to pass on their technological know how in developing a production bike more race-ready than ever before.
Resting on their laurels is not something Suzuki have ever done nor about to start doing, and with the evolution in motorcycle technology rapidly changing Suzuki have shown that they are not about to be left behind either as the new fuel injected RM-Z250 demonstrates. But it takes more than that to convince you to part with your hard earned cash, but trust us; this thing really is the bee's knees.
Let's not beat about the bush here, the new RM-Z250 has got to be the best looking bike in its class, with its aggressive styling and new graphics. Even the front number plate gets the treatment with a couple of air intake scoops to help divert extra air to the radiators for that all important cooling, and although it has a brand new chassis the overall riding position has not been compromised in any way and the overall ergonomic package is spot on.
The new batteryless fuel injection system is powered by a double lightweight magneto generator and incorporates a 44mm throttle body with progressive throttle linkage, 16-bit computer and unique capacitor-assisted starting system, which in essence means it should be easier to start.
Engine modifications and new cylinder head and a slightly taller crown on the piston means improved compression ratio, ensuring a much more punchy motor, and modifications to the crankcase sees less oil being carried meaning less drag on the engine. Gear ratios have been improved along with the shift mechanism and modifications have been made to the suspension and swing arm in order to improve stability.
The aluminium cylinder is coated with Suzuki Composite Electro-chemical Material (SCEM) to improve heat transfer and durability, and to improve the cooling efficiency the radiator hose has been re-routed. So far so good then.
AS soon as you pull on to the track you get a hint of what this bike has to offer, the instant response off the bottom leaves you wanting to open the throttle further to see where it might take you, and in the deep sandy conditions of Desertmartin after days of rain prior to the test, that was pretty impressive indeed.
It didn't stop there either, and as you changed up through the gearbox the motor responded in the most emphatic way. The 2009 was already a good bike but was possibly just shaded by the strength of the Kawasaki motor, but riding the new Suzuki in such testing conditions, you can feel that the development of this bike is going in the right direction, and this of course is a direct result of testing in race conditions in the toughest competitions in the world.
With the new chassis, whilst the changes may only be slight - those being thicker walls in the lower frame tubes and slightly shallower side rails - the overall feeling is one that leaves you having to think long and hard about whether or not there is anything to find fault with; it just has this air of familiarity about it, of comfort, where you really are made to feel very much a part of this motorcycle.
Some of it has to do with the new fuel injection system seeing the old plastic fuel tank being swapped for a smaller and possibly slightly narrower aluminium version (to house the EFi system) which sees a reduction in capacity shrink from seven litres to six and a half. It also helps that the firm, narrow seat and nicely shaped tapered Renthal handlebars offer the optimum in ergonomics and overall riding position.
In the turns the RM-Z250 was just sublime, and you could pretty much do what you wanted with it; it didn't matter whether you were turning across a flat turn or trying to change direction over the rutted terrain, the front end was just so positive, and this was one of the few areas where this bike needed to improve over the 2009 model, which it easily has.
And in the ruts or the berms it was difficult to find fault with, and once it was in the turn you could just lean in, push the bike down with minimum effort, apply the power and before you know it, you're already out on to the straight and powering off into the distance. And it's here where you notice how well that the motor picks up, a combination of a new swing arm, new gearing seeing the sprockets go from 12/48 to 13/49 meaning a slightly longer wheelbase, and the improvements to the rear suspension also go a long way to improving overall traction and stability.
There were not too many bumps around Desertmartin to test the front and rear suspension combination, but on another test recently on a hilly circuit with bumps on downhills, you could feel that the overall balance was just spot on; sometimes you get a bike with a good rear shock and soft forks and vice versa, but the RM-Z250 was just perfectly balanced, and as a result the overall ride ability is everything you want it to be, and more. However, for those who are much more serious about their riding/racing then for an extra few quid you can buy into what is essentially your own tuning kit. Read on.
For those who like to tinker with engine settings in order to get the most out of your motor, Yoshimura have created the 'MX TUNER' which is a neat box of tricks designed with the rider in mind and enables you to change the 'jetting' with ease.
The obvious advantage with it is that in order to make the most of your engine's performance in the way that you used to have to by changing your jetting, you do not need to dismantle your carburettor to access your jets - because there are none. Instead you can alter the fuel volume and ignition timing to suit certain circuits and atmospheric conditions, quite literally, at the flick of a switch. In all there are three mapping settings; standard, slightly leaner, slightly richer.
The magic box connects to a plug (coupler) at the back of the right radiator cover, via a grey coupler (richer) or a white coupler (leaner), and with the flick of couple of switches and the twisting of a couple of dials on the MX Tuner, you can advance the ignition and go richer and leaner as you prefer. All the riders on the test tried various settings to suit them but the impressive thing about it all was the ease and the speed in which this can all be done.
Other similar systems require a laptop, but this system is much simpler and there's no danger of whacking in an insurance claim for a new computer due to sand getting into the system. I opted for an advance in the timing which worked off the bottom but made it too lean mid-top, but was able to rectify this by going richer to bring it back and improve the overall spread of power at the flick of a switch (conditions were cold, and going richer was the way to go).
On my 1996 Yamaha GP bike we were using map technology via a laptop and back then it was in its infancy and available to less than a handful of teams, so I am not that surprised to see how this system has evolved and how Yoshimura have been able to take this particular area to another level in terms of its availability to the average punter. Of course the GP Teams will still be using laptop technology for a more refined setting, but in terms of us being able to try to gain that little bit extra this is an important step in tuning development as well as for the future of EFi.
What's new? 2010 Suzuki RMZ-250F
Battery-less fuel injection systemRe-designed cylinder head
Revised cam timing
Updated intake ports
New stronger con rod
New silencer
Re-designed chassis
New swingarm
Revised suspension settings
Improved cooling
New stylish body work
New 'MX Tuner' by Yoshimura
SPECIFICATIONS - 2010 model Suzuki RM-Z250
ENGINE
Type: Single cylinder, liquid-cooled, DOHC four-stroke
Bore x Stroke: 77.0 mm x 53.6 mm
Capacity: 249 cc
Compression ratio: 13.5 : 1
Lubrication: Suzuki Advanced Sump System
Fuel system: Battery-less fuel injection
Starter system: Primary kick
Transmission: 5-speed constant mesh
Final Drive: Chain
Clutch: Wet multi disc
CHASSIS
Type: Twin-spar aluminium frame
SUSPENSION
Front: Upside-down Showa 47mm telescopic forks, with pneumatic/ coil spring, oil damped
Travel: 310 mm
Rear: Swingarm with link type suspension system & Showa piggy-back-reservoir shock
Travel: 310 mm
BRAKES
Front: Disc
Rear: Disc
TYRES
Front: 80/100-21
Rear: 100/90-19
DIMENSIONS
Overall length: 2,170 mm
Overall width: 830 mm
Overall height: 1,270 mm
Wheelbase: 1,475 mm
Seat height: 955 mm
Kerb mass: 105 kg
Fuel capacity: 6.2 litres
FOR A FULL TEST, SEE T+MX NEWS, FRIDAY, DECEMBER 18, 2009
Specification:
