Fixing The 2011 Suzuki RM-Z450 – Dirt Rider Magazine

By: Editorial Staff

Monday, April 18, 2011

/></a> <p class="wp-caption-text"></p> </div> <p>After the shootouts were over, the guys at Dirt Rider were kind enough to let me grab the 2011 Suzuki RM-Z450 and do what most people dream of: Basically, further test the motorcycle and decide what I would like to fix up on the yellow bomber. I went out and rode different tracks in SoCal like Glen Helen, Racetown 395, Competitive Edge, Cahullia Creek and even my own private track out in the desert. I really wanted to get as comfortable as possible on sag settings, control position and clicker settings, so I spent some time tweaking those. After I’d done all that I could with the stock components to get to where I liked the bike the most, I decided to nail down some mods and see how much improvement I could achieve with this AMA SX/MX-winning machine.<strong>Engine</strong><br /> The RM-Z450 is not an exciting bike by any means. It comes on smooth, rolls into the midrange and pulls decently up top, but none of that makes you all warm and fuzzy inside. I wanted to find a little more throttle response, grunt off the bottom and better overrev pull up on top. I chose Yoshimura to handle the motor needs for this project. Factory Suzuki runs Yoshimura products, so I figured I couldn’t go wrong; the company obviously knows the bike very well.We chose three Yosh components to achieve the performance gains I was looking for out of the RM-Z. First order of business was a carbon RS-4D race muffler full system, then a PIM-2 device and finally a Yoshimura Data Box.Bolting on the new RS-4D Ti/carbon muffler system gave the bike an instant jump in horsepower and improved the throttle response as well as the second-to-third-gear pull that I was looking for. Top-end was even increased slightly and without much sound increase over the stock muffler. The PIM-2 device was then added. This simple fuel-injection unit comes with two preloaded maps (one for the slip-on exhaust and one for the full system) and simply plugs into your existing wiring harness. This altered the fuel mapping and boosted power throughout the bottom-midrange pull. We also had Yosh’s Data Box installed, which allowed me to adjust the fuel mapping even further right there at the track with a laptop using the Yoshimura software. The Data Box plugs right into the PIM-2 device, and I could easily fine-tune where I needed a little better air/fuel ratio. I could read what rpm needed more or less air/fuel to get the best possible air/fuel mixture. I also got a little better fuel mileage along with enhanced throttle response throughout the rpm range.Finally, a complete Hinson clutch assembly was bolted up to handle the increase in horsepower and also help improve clutch plate life. The Hinson clutch basket, inner hub and pressure plate offers an exact feel throughout a long moto without clutch fade.<strong>Suspension And Handling</strong><br /> With the stock suspension being a little too soft on hard landings and too harsh on small chop, it was a confusing setup for me. I had the fork dive too much in the corners but also deflect on small braking bumps. The shock also needed to have more damping at the end stroke for hard slap-down landings.I relayed all this information to the guys at RG3, and to my surprise I was completely happy with what they came up with on the very first try…and I am picky! I was prepared to send the suspension back a few times to get it to where I like it, but the RG3 techs have done their homework on the Suzuki. Their fork performed better in the small braking bumps but also held up in the stroke more consistently coming into the corners. I had great control entering turns and could start my corner or pivot sooner than before. The shock felt like it had improved bottoming resistance on hard, flat landings, and I could get more aggressive with my riding. The bike had a balance that it didn’t have before and gave me more confidence while attacking the track everywhere.<strong>Miscellaneous Mods</strong><br /> With that, I added a few trinkets to the Zook that I thought would look clean and still be functional. I put on a Renthal 996 Twinwall handlebar with a pair of half-waffle medium grips. I also added a Renthal 51-tooth sprocket and a Renthal Gold HD chain. A complete One Industries Delta graphic/seat kit offered that clean new look that makes the bike pop in photos. Next was a buttery-smooth clutch adjuster by Works Connection with red accents, which may or may not make me faster in whoops but definitely made the clutch pull feel very light and easier to adjust on the fly. Yoshimura also provided cool red engine plugs and chain blocks to add to the bike’s bling factor. Lastly, I put on a pair of Bridgestone 403/404 tires to help the Suzuki stick to the ground better in soft to intermediate conditions. <div><a href=/></a> <p class="wp-caption-text"></p> </div> <p><strong>Aftermath</strong><br /> I didn’t need a lot of mods to get the RM-Z450 to work great. To me, the finished product is how a bike should be: Exciting to ride and controllable enough not to wear you out in 15 minutes. The aftermarket companies I used made the RM-Z come alive, and with their help we custom tailored it to how I like to ride/race a dirt bike. All of these fixes make a difference in their own way. Above all, these companies achieved a sizable improvement in my confidence on the bike. And isn’t that what fixing an MXer is all about?<strong>Parts List</strong><strong>Yoshimura:</strong> <a href="" rel=”nofollow” onclick="javascript:window.open(www.yoshimura-rd.com
Yoshimura RS-4D carbon fiber muffler: $1,095
Yoshimura RS-4D carbon fiber muffler: $1,095
Yoshimura Data Box self-mapper with stainless steel bung: $429
Yoshimura oil plug kit: Call for pricing
Yoshimura chain adjuster blocks: Call for pricing
Renthal America: www.renthal.com
51T black Ultralight sprocket: $64.95
13T Ultralight grooved sprocket: $32.95
Works gold chain: $103.95
Half-waffle medium-compound grips: $12.95
RG3 Suspension: www.rg3suspension.com
Smartvalve kit: $199.95
Fork and shock revalve including oil: $479.40
Hinson Racing: www.hinsonracing.com
Complete clutch kit, including basket, inner hub, pressure plate, steel/fiber plates, HD clutch springs,
clutch cover: $1,089.99
Works Connection: www.worksconnection.com
Elite clutch perch: $149.95
One Industries: www.oneindustries.com
Technogrip seat cover: $59.95
Bridgestone: www.bridgestone-firestone.com
403/404 tires: See your local dealer
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