Tests

2013 Suzuki RM-Z450 - First Impression

August 2, 2012

Captions By Chris Green • Photos By Max Mandell

The visual changes here are minor, but that’s not what counts. The engine, chassis and suspension all saw some serious improvement over last year—and that’s what you should be paying attention to.

In my mind, the RM-Z450 has always been something of a gentle giant. The power is smooth, the handling is stable and the bike is not violently fast or difficult to ride. The 2013 Suzuki RM-Z450 falls in line with this personality type in that the overall package is more usable and less race-oriented. Don't get me wrong, you could absolutely line this stock machine up at a local motocross and ride away with a trophy. But compared to a bike like the 2013 Kawasaki KX450F, the Suzuki doesn't feel overly scary. The power comes on strong and gets to the ground well, though our test bike's piston felt 'heavy' like the engine needed another three or four hours of break-in. The RM-Z shifts well with noticeably good clutch engagement. I was fairly surprised when I heard that 'Zook was putting the Showa Separate Function Fork on this machine, but a couple of laps around a mellower version of Suzuki's jumpy Supercross test track showed that the front-to-back weight feel of the bike is in proper balance. The fork took hard hits fairly well but you can tell it's using the full stroke; with a heavier pilot on board this 2013 Suzuki RM-Z450 might be sprung too soft out of the box. Straight-line traction and acceleration felt decent, with my biggest gripe being that you have to be incredibly deliberate when getting the Suzuki to turn on flat terrain. Having even the smallest rut or berm to push against aids cornering tremendously, whereas changing direction on flat segments simply takes more rider input and effort. There are a number of small details on the 2013 Suzuki RM-Z450 that are pretty cool—I still geek out on the aluminum fuel tank—and all together this is a fairly well-rounded package.

2013 Suzuki RM-Z450 motocross machine:

The muffler’s internal parts have been redesigned and it is 40mm longer on the inside while the can remains the same length. The goal here was to gain controllable bottom- and mid-range torque without losing anything up top.

We first saw Showa’s Separate Function Fork (SFF) on the 2012 Kawasaki KX250F. Here is the second generation of the SFF unit on both the 2013 Suzuki RM-Z450 and RM-Z250. The right leg contains the spring and the left leg contains the cartridge assembly, which tackles damping. The diameter of the fork inner tube has jumped up from 47mm to 48mm for 2013, which Suzuki says optimizes stability and absorption performance. Going with the SFF fork also lightened up the Suzuki 450 by two percent.

Suzuki’s unique aluminum tank looks rad and always has us drooling over its factory ambiance. The fuel capacity is 1.6 gallons. And the width of the side shroud where it meets the seat was changed slightly to make for a more seamless transition when moving around on the bike.

The linkage mounting bolts were increased from 12mm to 14mm to increase the rear end rigidity and also prevent them from spinning. The changes here were minor on the 450, but the 250 was reworked a bit more. Check back to www.dirtrider.com next week when we get our RM-Z250 for more tech updates on Suzuki’s smaller four-stroke.

The changes to the engine-mounting bracket may not be noticeable, but the shape and mounting position of the engine bracket were altered to achieve a better rigidity balance.

The location of the connecting couplers has been moved from behind the front number plate (difficult to reach) to being slightly hidden behind the left side shroud. Changing the couplers is noticeable and we were much more inclined to pop the little plugs in and out throughout the day.

There were countless changes made inside this silver 450cc box so I’ll shoot them off quick. If you were to crack the cases on this bad boy you would find a new intake camshaft, lighter piston and DLC (diamond like coating) piston pin, new connecting rod, redesigned transmission, thinner crankcase read valve, new cam chain guide, stator coil, reshaped shift cam and a new oil strainer with a stronger magnet to catch unwanted debris. The RM-Z450’s new piston is 13 percent lighter thanks to a reshaped piston skirt, shorter piston pin boss and a lighter connecting rod. The cam’s intake timing was changed as was the cam’s working angle and lift amount (by 0.4mm) for a smoother characteristic. A ton of work went into the tranny to provide the rider with smoother shifting. The shape of the gears were changed on second through fifth by going from three dogs on the gear from four. Fewer dogs allow the gears to drop into place quicker and smoother. To wrap it up the cam chain guide has been changed to better resist abrasion making it a more reliable part.

The 2013 RM-Z450 received a ton of changes, most of which are unnoticeable while looking at the bike. The bodywork stayed the same but the front number plate is now yellow and the back fender black. This applies to both models making it a bit difficult to tell them apart. The only visual detail that gives these two yellow MXers away is the white side plate handle on the 450 and the black side plate handle on the 250.