The Suzuki RM Z250 is a nimble dirt bike equipped with a 249cc engine and a five-speed transmission.
Aimed at entry-level riders it combines a sleek race-ready appearance, advanced rider technology and a manageable amount of power.
In this article we’ll take a closer look at the RM Z250’s most common problems…
Rigid Suspension and Chassis
One of the main issues with the Suzuki RM Z250 is its overtly sprung suspension and rigid chassis.
While a hard suspension is an effective quality for a dirt bike to have in theory, the execution on the RM Z250 leaves much to be desired.
- The stock Showa suspension’s tuning is acceptable on a prepped dirt track for a short time, but in true off-road scenarios, it can be too rigid.
- The suspension is unforgivingly sprung in its own right, bouncing the rider out of the seat when rolling over rough terrain and landing from a jump.
- Combined with the durable yet rigid frame, the springy suspension makes for a stiff and uncomfortable ride.
Some riders solve this common RM Z250 problem by upgrading their suspension to an aftermarket package that’s either softer or more adjustable.
Others feel cheated that they have to put money into a brand new modern dirt bike when most of the competition comes stock with superior suspension.
Still, the price point on the Suzuki is lower than most other 250 dirt bikes on the market with similar durability and power, a fact that some riders say evens out the cost of an upgraded suspension.
Faulty Throttle Position Sensor
If the throttle position sensor on your Suzuki RM Z250 fails, your engine won’t start. Suzuki equips the modern RM Z250 with a red light that blinks a specific amount of time to alert the rider of the specific failure.
In the case of a faulty throttle position sensor, the red light will blink once, then pause, then blink four times.
That said, the baffling thing about some of the Suzuki Throttle Position Sensor (TPS) failure scenarios was that it would fail randomly and blink to alert the rider that the TPS was the culprit, but eventually, it would start working again.
While moisture, grime, and physical damage can impact any safety sensor (on any make and year model moto), the throttle position sensor on the RM Z250 was a repeat issue especially common on the 2011 – 2017 year models.
- One of the pins on the TPS was frail enough to break off during excessive engine vibration.
- Once snapped off, the pin would break off in the sensor connector.
- Because the pin was lodged in the connector, the connection would sometimes be functional, depending on if contact was being made between the connector and the sensor.
- During excessive engine vibrations or riding over rough roads, the connection would break, the pin would rattle out, and the bike would stall out.
The solution is to replace the faulty throttle position sensor.
Most consumer reports claim that Suzuki is aware of this common failure and almost always accepts responsibility, replacing the TPS unit for free.
Failing Electronic Fuel Injector Causes No Spark
One problem consumers report about the Suzuki RM Z250 is a failure with the Electronic Fuel Injector or EFI. Once this component fails, the bike will stall, and the ECU will fail to spark the ignition process.
The electronic fuel injector is the component responsible for injecting fuel into the airstream when told to do so by the Electronic Computer Unit that governs the whole engine operation of your RM Z250.
- The ECU uses a series of sensors to form a data map of the air and fuel systems.
- If there’s a problem with one of the sensors, the information it’s receiving is wrong, and it will inject fuel or air at the wrong time.
- Therefore, if there’s sensor interference, the ECU will kill the engine rather than attempt to govern its operations without all the information.
- This safety feature prevents collision, injury, and engine damage.
That said, since their ECU shuts the EFI off at the first sign of interference with any of the sensors, faulty EFI can be hard to detect.
If all the sensors are working, but moisture or dirt simply interferes with one of the sensor signals, you should be able to reset the whole system by unhooking your battery terminals and reconnecting them.
If that doesn’t work, experienced home mechanics have been able to isolate their RM Z250s electrical failure by using the service manual to trace their power output from the stator to the various EFI system sensors and components until they find the dead spot in the current.
That said, electrical work on even a simple dirt bike can be technical on a modern, EFI-equipped moto.
We suggest you have a Suzuki technician diagnose the other EFI failure using their CPU unit, as it could save money and hours of electrical troubleshooting.
Valves Wear Out Quickly
If a Suzuki Rm Z250’s valves are out of adjustment, your engine will experience running issues and starting problems due to negative impact on air:fuel flow. Worn valves fall out of adjustment quickly, and the valves on the RM Z250 wear out quickly.
- Simply put, valves are mechanisms in your cylinders that control the flow of air and fuel into the cylinder’s combustion chamber, where combustion takes place to maintain the engine power.
- Valves need to be adjusted as part of routine maintenance, or they will fall out of time or sit improperly.
- Valve adjustment is a technical job requiring special tools and a working mechanical knowledge of the RM Z250’s engine.
- Both skipping out on a valve adjustment or performing an improper adjustment can lead to an RM Z250 that won’t kick start.
That said, there are numerous consumer reports claiming the valves were going out of adjustment despite the fact that the dirt bike was taken to Suzuki’s dealership technicians for valve adjustment services per the recommended intervals.
Eventually, the valves are discovered to be worn out earlier than expected, therefore throwing themselves out of adjustment during regular operation.,
- Some riders install titanium valves rather than replacing their worn valves with more of the same stock parts.
- Titanium valves are more resilient, staying in adjustment and lasting for much longer than the valves that come in stock on the RM Z250.
- Some reports claim the valves wear early due to a faulty camshaft decompressor, but we were unable to confirm this theory.,
Fuel Lines Collapsed
Collapsed fuel lines are one of the most difficult problems to detect on a Suzuki RM Z250. This is because the problem manifests symptoms of a clogged fuel filter or a faulty fuel pump.
Riders report replacing these two items before finally deducing that the fuel lines themselves are the reason fuel flow is constricted.
Still, fuel pump failure isn’t unheard of on the RM Z250 either, meaning it’s important to eliminate it as potential before moving on to fuel line replacement.
- Remove your RM Z1250’s fuel tank.
- Hook the pump connector up to a 12V battery.
- If you hear the pump running and see the flow of fuel, your pump isn’t the problem.
Next, you’ll want to examine your fuel filter for clogs, as a simple dirt clog in the filter is often enough to inhibit fuel flow on a dirt bike.
A clogged fuel filter will cause the air: fuel to run lean and will emulate the symptoms of a pinched fuel line.
If the filter checks out, your bike may have fallen victim to the collapsed fuel pump problem.
- The fuel pump assembly includes a three-inch fuel line.
- On some models, the integrity of the fuel line was less than it should’ve been.
- If the fuel line isn’t constructed up to the standard spec, it will soften up when submerged in fuel.
- After enough time, the softened hose will collapse completely, hindering the flow of fuel.
Suzuki seems to have a good reputation for warranty accountability and will often replace the hose for free.
Still, some riders opt to install a stainless steel spring under the line to provide extra support to avoid collapse.
That said, we suggest you inquire with a Suzuki technician if you suspect obstruction to your fuel flow before installing extra parts for support.
Pros and Cons
- Rugged and Reliable Overall
- Excellent Cornering and handling
- Effective Stopping Power
- Durable Chassis
- Straightforward Dirt Bike Concept
- Looks Tough and Stylish.
- Fun to Ride
- Feels Heavy While Riding Slow
- The suspension is uncomfortable and too hard.
- Rigid Frame/Chassis
- Power and Performance can be Underwhelming.
- Lack of Features
- Valve Adjustments make the RM Z250 High Maintenance
What Do the Reviews Say?
“Suzuki’s motocross bikes are praised for their cornering capabilities, and the newest RM-Z250 is no different. Brown said that it corners easily while remaining stable on the straights. “Even with unusually stiff suspension, the bike will still rail every inside out on the track. During testing, the KYB Air-Oil Separate (AOS) coil-spring fork and KYB shock proved to be very stiff. The fork’s stiffer spring rate worked well on jumps, flat landings, and under heavy loads, but that was not the case for smaller chops during corner entry. Improving the suspension performance required lots of adjustments. The front is adjustable for compression and rebounds damping while the rear is adjustable for spring preload high-/low-speed compression damping and high-/low-speed rebound damping.”
“Despite it having stiff suspension and not producing the most horsepower, the RM-Z250′s suspension, brakes, and wheels are very high quality, and it still has plenty of power, especially for returning riders or those moving up from a 125cc two-stroke.”
“…the bike’s ergonomics were mostly on point, the only minor criticism being the bike felt a little tall yet compact. The seat is very flat, and the bike is narrow between the rider’s legs. The Renthal Fatbar 821-bend handlebar does not have much rise, especially compared to others in the class that is equipped with Renthal’s 839-bend unit.”
“In order to find out what the 249cc liquid-cooled four-stroke was made of, we ran it on our in-house dyno to learn that it produces 36.3 hp at 11,500 pm and 18.6 pound-feet of torque at 9,100 rpm. This performance test was followed by on-track testing by contributor Allan Brown. Brown wrote that while the RM-Z is not the strongest on the dyno, it is still a well-running engine, and part of the reason for its not having better results on the dyno is that the power is focused in the midrange as opposed to the top-end like its competitors. The five-speed transmission first through third gear is fairly close, with a larger gap between third and fourth.”
What’s the Resale Value of a Suzuki RM Z250?
What are Some Alternatives to the Suzuki RM Z250?
|Suzuki RM Z250||$7,899||45|
|KTM 250 SX-F||$8,999||45|
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2021 Suzuki RM-Z250 Buyer’s Guide: Specs, Photos, Price | Cycle World