Suzuki invited the press to the Castillo Ranch in Los Alamos, California, this week to try their latest 450-motocross machine. Suzuki actually unveiled the bike at the Glen Helen national this year, so we knew it had the Showa air fork and a change to the frame; those things were visible to the eye. But we still didn’t know what was going on underneath that yellow plastic. Up in the serene hills of Jim Castillo’s motocross playground we found out.
New Stuff
The fork is the big change, and it is the same TAC unit being used by Kawasaki on their 450. However, it is slightly different in design, but identical in function, as the Honda Showa TAC. The new fork provides plenty of adjustability and a more positive feel to the riders and, when set up correctly, greatly improves front-end traction. Getting it set up right is the key and we are all going to have to go through a learning curve on these air units.
Another major change that was adapted from Suzuki’s global factory racing efforts is a change to the frame. The front cradle where the two sides come together is noticeably different, and looks like material has been removed. Suzuki confirmed this and said they wanted more flex there and less flex in the rear near the shock mount. The frame has been beefed up near the shock to reduce flex in that segment of the frame. There is all-new ECU mapping in this model. I know what you’re thinking: That’s about as exciting as bold new graphics. That’s what I think when I hear that. But this change actually made a significant improvement to throttle response. One of the first things I noticed was how much sharper and responsive the initial turn of the throttle is. The rear wheel now feels very connected to your right hand.
The rear axle diameter has been increased to tighten clearances in the swingarm and improve rigidity. The starting gear design has been changed, and Suzuki assures us the bike is now easier starting than ever before. Protective plastic like the rear disk guard, rear caliper guard, and engine case guards are now black. The graphics are both bold and new, so that’s exciting. There is also a start assist device on the RMZ that retards the timing for starts on concrete or very slippery conditions.
Lastly, the exhaust system has been revised to lower decibel levels and also improve power. The changes made to the exhaust work in conjunction with the new ECU mapping.
Where the Rubber Meets the Dirt
First things first: I don’t weigh enough to ride this bike, apparently. Go ahead and insert ‘You must be THIS tall to ride this ride’ joke here if you’d like. We attempted to set the sag, but before we could get to the recommended 105mm, the spring ran out of tension. We got to about 103mm and just went with it. Their target weight for this shock must be close to 200lbs.
Once we all had a good laugh at my expense, I hit the track and immediately noticed the responsiveness of the bike. The instant you crack the throttle the new RMZ jumps to life and accelerates. This is not a lazy engine. Through the rest of the RPM range, the Suzuki is meaty but manageable and offers up all the power you’ll need. On last year’s model, I always felt in-between gears down low and, as a result, added a tooth to the rear sprocket to find the sweet spot. With the mapping on the 2015 version, the stock gearing works perfectly.
Some of the other changes weren’t as noticeable. Suzuki claimed the updates to the starter gear configuration would make it unbelievably easy to start. It seemed about the same to me. The frame changes are tough to feel because the fork has such a different feel. After removing some psi from the inner chamber and adding some high speed rebound to the shock we got the bike balanced, but I still had a ways to go to make it a perfect handling machine. I know I like the fork because I’ve gotten it to work really well—it just takes some time.
As a package the Suzuki is a fantastic motorcycle. The turning is still first-rate, and that is a trait many other manufacturers are envious of. The engine is potent and the chassis is comfortable and nimble. Yellow magic? Indeed.
