Despite finishing runner-up in this year’s 2012 450 Motocross Shootout, Suzuki’s RM-Z450 could be some riders preferred moto bike in part to its nimble handling paired with friendly and well metered engine performance. To further tailor it, we fitted a different handlebar, as well as replacing the well-worn chain, sprockets and tires.
With the exception of the handlebar bend the RM-Z’s ergonomics were well received by our testers. So we wasted no time swapping the OE-fitted Fatbar (672-01) for a Renthal Twinwall 1-1/8″ Oversized Handlebars. We opted for the 997 bend as it’s what we’ve traditionally been most comfortable with on other brands. Although the stock Suzuki grips are durable and have a nice feel we fitted a fresh pair of Renthal Half-Waffle MX Grips. These grips offer softer touch with added grip against gloves courtesy of the half-waffle texture.
Renthal offers a variety of different handlebars and grips based on rider preference. Pictured is the 997 bend.
Compared to stock the 997 bars are a little taller and don’t offer quite as much rearward sweep. Although they measured 6mm wider, to our surprise it felt a little narrower, which may be attributed to the reduced sweep. We also noticed that the grips transfer additional vibration from the engine which made our hands more tired faster compared to the stock set-up.
To date, we’ve accumulated 28 hours on our RM-Z including two trips to the Glamis sand dunes. Riding in the sand is notorious for stretching chains and dulling sprocket teeth. In fact, the stock chain had stretched so much that we had to remove a link just to make it fit. Plus it became so stiff that it no longer spun freely.
The fix was to fit a fresh Renthal 520 Off-Road Front Countershaft Sprocket, Renthal 520 Off-Road Rear Sprocket and Renthal 520 R1 Works Chain. Having been satisfied with the RM-Z’s final drive gearing (13/50) we elected to keep it the same but accidentally ordered a one-tooth larger sprocket (51).
Swapping out the parts is a snap as long as you have a basic set of hand tools, including an oversized wrench or ratchet (for the countershaft sprocket nut). Chain install gets really simple if you have a Motion Pro Chain Breaker, Press and Riveting Tool. The gearing change made the bike accelerate harder but narrowed the powerband slightly because you need to shift a bit more. If you ride at a smaller track then it actually works just fine but around longer tracks we prefer stock gearing. After a small initial break-in stretch the chain has maintained its length despite multiple rides. We’ll provide another durability update as we accumulate more ride time.
We accidently ordered a one tooth larger rear sprocket which increased acceleration but made the powerband not quite as versatile on a big outdoor track.
We’re big fans of the Suzuki’s stock rubber. Only problem is how fast they wear especially if you ride on hard packed terrain. Both tires were well overdue for replacement so we mounted up a Dunlop MX71 Geomax Hard Terrain Front Tire (80/100-21) and Dunlop MX51 Geomax Intermediate Rear Tire (120/80-19). We opted to run the hard terrain front as it works better on the vast majority of Southern California tracks. Out back we fitted a wider tire for more traction. Typically a wider back tire can make the bike steer slower but we didn’t notice a difference. What we did notice is how much grip the bike has at racetracks like Perris Raceway, Racetown 395 and Zaca Station.
Besides routine oil and filter changes as well as occasional air filter cleaning our RM-Z450 continues to perform flawlessly. Even with 28 hours the engine and chassis feel tight and we have plenty of brake pad left too, though we’ve noticed the propensity for the clutch to fade slightly during longer motos. The suspension feels like it could benefit from some fresh fluids and a spring rate change, too, which we’ll address in our next update.