Last week, Suzuki invited the motocross press to visit the legendary Castillo Ranch MX facility, where it would be unveiling the 2006 Suzuki RM-Z450, so we packed up the TransWorld Motocross Ford F-150 and made the five-hour drive to central California, anxious with anticipation.
In its first year of release, the ’05 RM-Z450 turned a lot of heads. In the capable hands of Ricky Carmichael, it won every 250cc Motocross National and came away the hands-down winner of the National Championship. In magazine tests and shootouts, the RM-Z came away with mostly runner-up honors, finishing a very respectable second behind the Honda CRF450R.
NEW FOR 2006
For 2006, Suzuki stepped up its program with several major refinements to the popular yellow thumper. To help with better throttle response and low-end power, a new camshaft and cylinder head specs were incorporated, as well as new shifting forks for smoother transmission shifting action. Suspension-wise, both ends of the Showa component set were revised, with the most significant changes occurring out back. A new 2mm shorter shock is outfitted with a stiffer spring and mated to all-new shock linkage that boasts a more progressive rate. The swingarm is beefed up considerably in its fattest section, and the front of the frame now sports a two-piece head tube section, replacing last year¿s single-piece version. Rounding out the changes worth mentioning are a handlebar-mounted hot-start lever and the new blue graphics and seat cover.
ON THE TRACK
Last year, we found that installing a bigger 50-tooth rear sprocket was the way to go to help improve the RM-Z¿s low-end throttle response, but the changes made to the new motor offer significant improvements; so much so that we found that a smaller 48-tooth sprocket works well on faster courses. Throttle response is crisp and the jetting is spot-on, as delivered. The RM-Z never hesitates or bogs, even when the throttle is chopped suddenly. The big Suzuki is certainly more powerful than its predecessor, and it works best on the track when kept in the sweet spot of the powerband: revving it out in each gear produces more noise and not necessarily more power. On the semi-tight Castillo Ranch course, we found ourselves in second gear in the tight sections, and in third everywhere else. As it was last year, the RM-Z450 powerplant remains one of the easiest to ride and most fun in the class. Don¿t mistake easy-to-ride and fun for ¿slow¿ though, the bike is plenty fast and more than capable of big holeshots!
The biggest fuss at the pre-ride presentation was made about the bike¿s new rear suspension settings, and we can attest to the fact that the new shorter shock, stiffer shock spring and new shock linkage equal big gains in the handling department. Last year, the rear end of the Suzuki offered a harsh ride under acceleration in choppy conditions, and also had a tendency to swap unpredictably on super-hard landings (read: case outs). We were delighted to find that the new back end gobbles up the bumps much better than last year¿s did, and claws for forward traction while staying straight as an arrow. As a package, the Showa suspension is well balanced and the bike has a very predictable feel both on the ground and in the air.
One of the things last year¿s RM-Z450 did better than any other bike we¿ve tested was corner, and we were relieved to find that the new version is also a cornering master. No kidding here folks: the RM-Z 450 enjoys more front-end traction than we¿ve ever encountered on any other motorcycle, and this thing will turn under any bike out there. Off-cambers, flat slippery corners and ruts are a dream on the `Zook. Remarkably, the bike remains stable at speed. Though we don¿t attain the same top speeds as RC, we¿ve never had a problem with headshake or uncertainty on the RM-Z450. Furthermore, the bike raails wide, high lines with as much dexterity as it does the tight, slippery stuff.
We¿re sure that many riders will rejoice at the new handlebar-mounted hot start, but to be honest, we never even installed one on our ¿05 bike. Why? Because even when stalled in a crash, the RM-Z450 always starts up in one or two kicks, no matter how hot it is. The hot-start lever is more of a formality, as far as we¿re concerned.
We know what you¿re thinking: ¿Are these guys gonna criticize anything about this bike?¿ We sure are. We know that it¿s probably some sort of legal requirement, but the vulcanized throttle-side grip was manufactured in hell as far as we¿re concerned. The stock Suzuki grips are hard and uncomfortable, but worst of all the throttle side is practically impossible to remove without a bench grinder and 23 razor blades. The front end of the bike is also not helped at all by the Renthal Fat Bar, which provides a stiff and unforgiving ride. Suzuki would have been wiser to outfit the bike with standard 7/8¿ Renthals or even better yet, with the same Pro Taper handlebar that the race team uses. We swapped the stock bars out for a set of Pro Tapers and could immediately tell a difference in the comfort of the overall ride. Our last gripe lies with the stock Bridgestone M401 front tire. Though the larger 90/100-21 size is intended to offer a wider footprint and greater traction, the M401 is one of the most unpleasant tires we¿ve encountered and have yet to find a track condition in which it excels.
Overall, Suzuki has another winner on its hands with the RM-Z450, and the big yellow four-stroke is sure to be a threat come time for the TransWorld Motocross 2006 450cc Four-Stroke shootout. We love it!
Check out video of the new yellow big-bore thumper in action…click the Related link in the right-hand column.