RM-Z250 Four-Stroke
Notable updates to the ’04 Suzuki two-stroke motocrossers are mostly in the chassis area. While both the 125 and 250 feature revised motors, the big news seems to be the redesigned rear shock linkage. Although without pictures of the new linkage design in our press kit it is difficult to be certain, from the description provided by Suzuki it seems that the setup may be similar to the “Unit Pro-Link” design used on Honda’s CBR600RR as well as their RC211V V-5 race machine. How this design will work in an off-road setting is yet to be seen, but Suzuki is definitely doing something different with their rear suspension this year. Other changes to the 2-strokes are aimed at more power and improved rideability, although it is interesting to note that both the 125 and the 250 feature a 10mm lower seat height than last year’s bikes. Both motors are also claimed to have “more crank inertia”, meaning a heavier rotating mass. This is claimed to be for better traction. Dry weights are claimed at 192 lbs for the 125 and 212 lbs for the 250.
The real news in Suzuki’s ’04 MX lineup is the RM-Z250 four-stroke MX’er (pictured). Shared with Kawasaki, this bike will compete in the showroom and on the racetrack with Yamaha’s ’04 YZ250F and Honda’s new CRF250R. The motor uses a dual overhead cam design featuring titanium valves on both the intake and exhaust sides. The motor’s 77mm bore and 53.6mm stroke exactly match the specs of Yamaha’s current YZ250F. Lubrication is via a “semi-dry-sump” system, with the transmission being used as the oil sump while the crankshaft spins in a separate chamber. The crankcase construction is described as “thin-wall”, and the valve cover as well as both side covers (clutch and ignition) are magnesium to save weight.
The frame is a traditional twin-spar type, featuring D-shaped upper spars to keep the bike slim. The four-stroke 250 uses Kayaba suspension front and rear, and shares its all-new rear linkage design with the RM125 and RM250 two-stroke models. Some specifications are not final, including claimed dry weight (an all-important spec in this class).
We should have ride reports on the Suzuki two-strokes in the near feature, with a ride report on the 250 four-stroke a few months away. Stay tuned.
