2019 SUZUKI RM-Z250: THE ’19s VIDEO SERIES

The 2019 Suzuki RM-Z250 was the last 250 MX bike in the Dirt Bike Magazine test fleet. We already knew what to expect because we did a brief riding impression of the bike in Japan a few months ago. Once the production test bike arrived, it was pushed directly  into our 2019 shootout and thus had less track time than the other 250 motocrossers. Now we’ve had the bike for some time and have put more miles on it. As part of our video series “The ’19s,” here’s a little more information on the bike that Suzuki will be sending into the moto wars of 2019.

Suzuki’s 2019 RM-Z250 has all-new style and more pep in its step.
Suzuki’s 2019 RM-Z250 has all-new style and more pep in its step.

Suzuki treated the 2019 RM-Z250 to many of the same designs and updates that the RM-Z450 got for 2018 but with key differences. The most interesting of these is the move to dual injectors, similar to the system used for the Kawasaki KX250. A secondary injector is placed between the air filter and the throttle body, and it kicks in at high rpm. There is also a 30-percent-larger air filter intake aperture, a straighter outlet to the throttle body, a redesigned cylinder-head intake, and exhaust port with increased fuel pressure designed to improve fuel/air atomization.
The entire exhaust system has been redesigned 99mm longer and features an internal tapered head pipe too. The fourth generation of Suzuki’s multi-level holeshot assistance system (called S-HAC) debuted on the 2019 model and retains the use of color-coded couplers to adjust the power delivery. Sorry to say, it did not get electric start.

The 2019 RM-Z250 received the same overall styling updates as the 2018 RM-Z450. The plastic is now interchangeable.
The 2019 RM-Z250 received the same overall styling updates as the 2018 RM-Z450. The plastic is now interchangeable.

In the chassis department the frame is all new for the 2019 RM-Z250, but very similar to that of the new 450. Compared to the older 250 frame, it’s narrower, lighter and more rigid. The new design also repositions the motor with more of a forward rotation. Unlike the 450, the RM-Z250 uses KYB suspension. The fork has dual-coil springs, and the rear shock has four different ways of adjusting the damping, plus new linkage. The front brake rotor is larger. The rims are now D.I.D Dirt Stars, and the tires are Dunlop MX33s.
Our riding session was limited to four hours between rainstorms, but it was enough to get a feel of the new bike. Frankly, we were a little apprehensive when we learned that the bike shared so much with the current RM-Z450.

The front disc diameter has been increased from 250mm to 270mm, and the brake pad material has been changed to improve stopping power.
The front disc diameter has been increased from 250mm to 270mm, and the brake pad material has been changed to improve stopping power.
The frame and swingarm are all new. The aluminum frame spars have changed to a hollow square section that does away with the internal rib, decreasing weight while increasing torsional rigidity.
The frame and swingarm are all new. The aluminum frame spars have changed to a hollow square section that does away with the internal rib, decreasing weight while increasing torsional rigidity.
The RM-Z250’s fuel-injection system now features two injectors. The newly configured cylinder head’s intake and exhaust ports are designed to improve combustion efficiency.
The RM-Z250’s fuel-injection system now features two injectors. The newly configured cylinder head’s intake and exhaust ports are designed to improve combustion efficiency.
The exhaust pipe was lengthened by 99mm, with the internal diameter tapering from 35mm at the cylinder head to 45mm at the muffler.
The exhaust pipe was lengthened by 99mm, with the internal diameter tapering from 35mm at the cylinder head to 45mm at the muffler.

That bike has a strong fan base, but it still took a beating in our 2019 450 MX shootout. Most riders feel it’s unbalanced with a distinctly rear-high riding attitude. Any attempts to deal with that attitude seem to compromise the bike’s traditionally strong cornering ability.
We were pleased to learn that the new chassis is actually much better suited to the RM-Z250. In fact, most of the 450’s weaknesses were either lessened or nonexistent on the 250. It still corners exceptionally well, and the KYB spring fork setup is a huge improvement over last year’s air units, especially on small consecutive bumps. The rear shock has good, predictable action and has four different clicker adjustment options. This can be confusing to keep track of at times, though. The bike had a rear-end-high feel at 105mm of sag, so we increased it to 110mm and added a few clicks of rebound damping to slow the action down. After these adjustments, the bike seemed surprisingly well-suited to Mark. That might be a cause for concern for the typical 250 rider, who is around 20 pounds lighter than Mark. With a little math, we figured out that the spring rates on the machine we tested were almost identical to that of Suzuki’s 2018 RM-Z450.

For 2019 the RM-Z250 retains the use of Kayaba suspension components with a dual-coil-spring KYB fork up front and redesigned rear linkage.
For 2019 the RM-Z250 retains the use of Kayaba suspension components with a dual-coil-spring KYB fork up front and redesigned rear linkage.

In the motor department, we feel confident that the RM-Z is stronger than the 2018 model. That bike, however, was significantly down on peak power compared to the rest of the class. The new RM-Z250 has decent low end but still falls off on top where most of the current 250s have improved dramatically in recent years. We noticed a big difference in performance when changing couplers. The lean (white) coupler improved overall performance, making the machine easier to keep in the sweet spot of the power curve. Using the standard (black) and rich (grey) couplers, we noticed a slight blubber off the bottom. We aren’t sure if this has something to do with the weather or sandy, muddy track conditions we dealt with. The bike was also oddly hard to start both cold and hot. Of all the bikes in the current 250F class, the Suzuki is most similar to the 2019 Kawasaki KX250.

The upper engine-mount brackets are now aluminum instead of steel, and the 2019 RM-Z250 has four brackets on both sides of the engine. This not only drops weight but is also designed to increase overall rigidity.
The upper engine-mount brackets are now aluminum instead of steel, and the 2019 RM-Z250 has four brackets on both sides of the engine. This not only drops weight but is also designed to increase overall rigidity.

 

The engine position was pivoted upward at the rear engine mount by 8.5mm measured at the crankshaft center.
The engine position was pivoted upward at the rear engine mount by 8.5mm measured at the crankshaft center.

Our impression of the new 2019 Suzuki RM-Z250 is by no means complete. For one thing, the bike we rode was a pilot production model and might not be representative of the final production units that will appear in dealerships. For another, we were riding on an unfamiliar track and our time was limited. Our next experience with the 2019 Suzuki RM-Z250 will take place sometime in late November  when a few production models will be flown to the U.S. for magazine testing. Keep check www.dirtbikemagazine.com to see a more complete review.

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