Suzuki practically based RM’s 2009 revision on the fact that it gets fuel injection, a first in motocross racing, and together with that it improved the entire bike in their attempt of becoming a track leader and the most feared opponent ever to be faced by the competition. Let’s see if they succeeded.
Now if the bike was to be fuel injected engineers plans didn’t include any early technology weaknesses so they turned their heads towards GSX-R road racers and inspired their new creation on the fuel injection system found there. A complete success, the new implementation uses a specially created Keihin throttle body and offers greater low-to-mid range grunt. Feeding the engine is done through an internal pump which doesn’t require a battery.
But once the fuel has reached its resting place intervenes yet another factor which makes the engine offer better response down low, through the mid-range, and all the way to the top end: the new design of the combustion chamber. Also, the intake and exhaust valve angle guides have been narrowed and squish areas increased in order to achieve better air and fuel mixing and implicit a bigger bang in the cylinder.
Intake efficiency was taken to a whole new level due to the new intake port angle and cam timing, while the exhaust port and cam timing exploit better the engine’s bangs and gain even more performance.
Very ingeniously, the front fender has a sloped-down shape with the purpose of guiding the air current to the air ducts and offer better cooling. At the rear end, the fender comes with air intakes on each side, a deciding factor for intake effectiveness.
The next, best and natural choice was to mate the redesigned engine to a 5-speed transmission that will get the best out of it. That was also made possible through the link type shifting mechanism.
For 2009, Suzuki decided to go for the semi-dry-sump lubrication system featuring separate oil chambers for the tranny and crankshaft using the tranny as the oil sump. This leaves room for lowering the crankshaft, reducing the engine height and has the rider more in control with a lower center of gravity.
In what concerns the chassis, most pieces are made of aluminum and Suzuki focused on delivering a quick-handling and yet properly-accommodating machine.
They started with the frame which was built from an aluminum alloy making the piece light and yet rigid, perfect for closed-course competitions. The great balance achieved between these two features of the frame also gave it the needed sharpness in what concerns the way it performs.
Showa delivered the suspensions. A fully adjustable cartridge-style front fork does a perfect job in keeping the weight down and absorbing the shock of the bumps. At the rear end there is the same formula only that this time it applies on shock absorber which keeps things in control through tight corners and in bumpy situations. Also, much to do with the rider’s safety feel through corners has the aluminum-alloy swingarm.
Brake rotors were designed to cool easily and not from the water in the mud as they deflect that very easily thanks to their new racy shape.
Also dealing with mud are the footpegs which offer maximum clearance between the mounting bracket and footrest. Well positioned in place, the rider can now concentrate on winning rather than on not falling down the bike.
In 2005 Suzuki introduced the big four-stroke RM model, one that would show a whole different face of competitions, totally different of the two-stroke idea. The bike came with a totally new 449cc liquid-cooled, single-cylinder, four-stroke, DOHC, four-valve engine and a frame that was made out of aluminum instead of steel. A Keihin FCR40MX was the feeding unit for the new powerplant and it has done the job properly in the first years of manufacturing until in 2007 Suzuki announced that fuel injection will come to motocross.
For 2006, the Suzuki engine was slightly retuned for more power output in the low-and-mid rpm range and the intake port was redesigned. Carburetor was reset and the ignition map improved. The extra power allowed slightly taller gearing, smoothing power delivery and redesigned shift forks improve shifting feel. Suzuki also repositioned the hot start lever for ease of operating.
There was the need for more control during tight cornering and over bumps so the steering head was modified and the swingarm had 5 mm taller arms.
2008 brought fuel injection to motocross and all the goodies you’ve read in the intro and the bike sells on as a 2009 model year, being more advanced than any other Suzuki motocrosser before it.
2009 Honda CRF450R
Wherever he’ll be heading, the biggest RM will have to share the success with Honda’s late arrived 2009 CRF450R. Not only the red blast is new as next year’s model, but it relies on the Programmed Fuel Injection (PGM-FI) with 50mm throttle body to induct the fuel into the burning chamber of the liquid-cooled, 449cc, four-stroke motor. This makes the CRF even more powerful than previous model years and a close-ratio five-speed transmission is here to provide a gear for every riding situation. Like every MX bike of this manufacturer, the CRF450R comes with Honda Progressive Steering Damper and one-off racing frame, suspensions and brakes.
2009 Yamaha YZ450F
Yamaha has also introduced the 2009 motocross lineup, with the YZ450F on top of it. Strongly revised and with a background full of successes, this is definitely among the strongest opponents the RM-Z450 will have to face. Even though it isn’t fuel-injected, the 449cc liquid-cooled, four-stroke, DOHC engine has the advantage of featuring five titanium valves and that is enough to make the Suzuki raise a few question marks.
2009 Kawasaki KX450F
Kawasaki enters the competition with a totally redesigned engine that has the same characteristics as the Yamaha one, only that it has four valves. What makes it even more threatening for the subject of today’s review is the fact that its motor is also fuel injected and features Keihin throttle body. It seems that the Suzuki-Kawasaki union has yet a strong word on the motocross track as even though any collaboration between the two makers has stopped the plans have remained and, as you can see, results keep on showing.