Wednesday, June 16, 2010 at 12:17PM Dan Paris The official Suzuki RMX450Z test: Trail bike or racer? Year s ago, back in the two-stroke era, Suzuki saw a lot of success off-road with their RM-250 based RMX. Over the years, like every other Japanese off-road bike, the RM evolved while the RMX stagnated and became watered down. Suzuki die-hards, and their own factory team, modified RMs for woods racing. The RMX was dropped. Suzuki four-stroked it into the zero-decade with the DR-Z 250 and 450. Both were good, solid trail bikes that were too fat and not really competitive without spending a fortune on modifications. Suzuki s serious off-road customers and their race team ignored them and continued modifying RM 125s and 250s.
This year s release of the all-new RMX450 raised a ton of questions. Would it be a fat, squooshy trail bike like a DRZ400? Would it be a mildly watered down motocrosser, more suited to GNCC racing than fun weekend trail rides? Besides that, where was it? Despite high demand for the new machine Suzuki dragged their feet bringing the RMX to Canada. We were stoked to finally get our hands on one and answer those questions once and for all. The RMX starts life as an RM-Z450. The fuel injected 450 is based on the motocross version, albeit with wimpier cams, a bunch of intake and exhaust neutering and the prerequisite electric starter. The transmission ratios are wider spaced then the RM-Z, but still reasonable for singletrack and moto use.
The frame is actually the 2009 RM-Z frame, which Suzuki R&D riders preferred off-road over the 2010 RM-Z frame for it s flex characteristics. The suspension components are the same as the RM-Z, only with slightly softer valving and spring rates. Compared to the typical Japanese enduro bike the RMX is a motocross bike with an 18 rear wheel. Compared to a MX bike the RMX is a softened up Cross-Country bike. You can see who the company was targeting right away; serious weekend warriors who like to mix up hardcore trail riding with some moto and XC time like us! Everything on the bike is tucked in nicely, it has a skid plate, radiator overflow tank, a back up kickstarter, a quick access airbox, minimal lighting and a kickstand. It s even got a digital trip meter with a low fuel light. About that low fuel light: The bike shares the same tiny aluminum fuel tank as the RM-Z.
The U.S press has whined about the RMX s small capacity and short range. Personally, with WEC enduro pits being no more than 40km apart, we think the slim ergos are well worth the trade-off in trail riding range. The aftermarket is working on bigger gas tanks for the cross-country and trail-riding crowd, but if you are an enduro racer you don t need to worry about it. We got around 50km to a tank of fuel, riding hard.
Anyway, all the enduro fluff added a big pile of weight to the RMX. It s about the same weight as other bloated enduro four-strokes, 272.3 pounds at the brochure. That s a whopping 25 pounds of pork more than the RM-Z motocrosser. The good thing is much of that fat can be carved off quite easily for racing. Even the battery and starter can be removed without affecting the operation of the engine or fuel injection system. The RMX kickstarts pretty easily too, so that isn t as dumb an idea as it sounds.
What s it like to ride? Well, it feels like a Suzuki. People either love or hate Suzuki s ergonomics. Let s just say our shorter riders loved the general feel of the bike. It also turns incredibly well, with a subsequent lack of high-speed stability. That s also a Suzuki trait, and one that we can happily live with.
The forks were awesome, generating no complaints whatsoever. Good stuff! The shock was a bit more confused, feeling like it needed stiffer overall valving. Our 160 pound intermediate ended up increasing the rebound damping 6 clicks and the compression 4 to get the back end to quit wallowing around.
Like most EFI bikes, dead engine electric starts are slow and take a few revolutions. It s much faster off the line just to kickstart it. In choked off stock form the bike is also slow. It won t wheelie in third without using the clutch. It won t rev. It flames out, is hard to start and runs really hot. The flywheel feels too light and the bike feels like it s geared too tall. The bike just feels dead, and wouldn t be a match for an RM-Z 250F. That drove us nuts! Our bike didn t have the throttle stop the U.S bikes have to meet EPA specs, but it did have the pencil sized exhaust tip and sealed up airbox. We brought it home, read all the other reviews saying the bike won t run right without that EPA stuff, and then we took that stuff out anyway.
Instant transformation! The bike was louder, about the same as the motocross version pretty much, which isn t exactly obnoxious but is still louder than we d like. Despite what we d read, our bike didn t run noticeably lean in our humid 30C weather with the exhaust and intake unplugged. There are aftermarket gizmos to add to the wiring harness to richen the EFI settings if you find the need. We didn t. In any case, we now had a real 450. A torquey, powerful yet very smooth 450. The gearing and flywheel weight felt just right, throttle response was crisp and power wheelies in any gear were possible, just like a 450 is supposed to do. It never stalled or got boiling hot after we uncorked it, and with the milder cams we actually preferred the smooth power delivery of the RMX to the motocross version.
We didn t have time to unbolt the other fat stuff that weighed it down, but the potential of the RMX to become a winning off-road race bike is huge. You can feel the weight of the highly placed battery, but the bike is pretty light on its feet for a 270-pound enduro bike. Stuff we didn t like? The airbox is quick access but it s a pain to get the filter itself in and out. We had to take off the seat and peek in with a flashlight to be confident it was seated properly. The bike is too gutless when corked up and too loud when it s uncorked. We d love to try it with an Akrapovic or FMF-Q silencer, guessing it would be a great compromise.
So what do we really think? Uncorked, the RMX became our favourite 450 of the year for its ability to do anything pretty well. It turns like crazy, feels flickable when you re playing on it and will run pretty hard on the MX track without being unruly in the woods. But if we were casual trail riders, used to typically fluffy Japanese trail bikes, the RMX wouldn t rate as highly. This is a weekend warrior machine, and that s good with us! So consider this our official beg to Suzuki Canada to let offroadmotorcycles.ca fiddle with an RMX for a few months so we can see just what it is really capable of! You can find full Suzuki RMX450-Z specs at: http://suzukicycles.com/product%20lines/cycles/products/rmx450z/2010/rmx450z.aspx Thanks to Suzuki Canada for providing our test bike and John Grant for de-spodify-ing us on film.