GEN3+ For Suzuki DR-Z400

XTNG GEN3+ Carb Dimensions

A: 48.80mm   
B: 58mm
C: 174mm
D: 96.50mm 
E: 65.30mm

Installation requirements:
Some OEM parts may need to be replaced to ensure perfect fitment of the GEN3+

•Front spigot OD: 48.50  mm – requires OEM intake boot, part number 13111-29F01
•Rear spigot OD: 58.50  mm – OEM air boot 13881-29FB0 recommended

If your bike came with the FCR39 (OEM air boot 13881-29F20, ID 54.50mm), it will not directly fit. However, you can heat the boot with a heat gun, slip it over the GEN3+ spigot, and allow it to cool and set — after that, reinstallation will be easy.



Through extensive real-world testing under extremely demanding mixed trail and off-road riding conditions, the GEN3+ 38 has also demonstrated excellent fuel efficiency and long-range capability on the DR-Z400 platform.

Test Configuration:
• Metering Rod Setting: 170 Clicks
• Fuel Assist Screw: 1 Turn Out
• Air Circuit: Open

Under this configuration, the DR-Z400 achieved the following fuel consumption results:

DR-Z400 Fuel Consumption
Fuel Consumption: 4.3 L / 100 km

Estimated Range per 10 L Fuel Tank:
≈ 233 km
≈ 145 miles
Fuel Economy:
≈ 88 km / gallon
≈ 54.7 MPG (US)

These results were obtained during real-world trail riding and technical off-road testing conditions, demonstrating the GEN3+’s ability to deliver both strong performance and outstanding fuel efficiency simultaneously.

XTNG GEN3+ is the latest evolution of our metering rod carburetor platform, combining the advantages of traditional metering rod systems with a fully optimized multi-circuit fuel control design. Built around a Variable Venturi structure and an internally pressurized venting system, GEN3+ delivers stronger low-end torque, faster throttle response, smoother power delivery, and more stable fuel atomization across the entire RPM range. Compared with traditional carburetors, it offers significantly improved altitude adaptability, fuel efficiency, and tuning convenience while still maintaining excellent top-end performance for aggressive riding conditions.

Internal Venting: Pressurized Fuel System

One of the most unique features of the GEN3+ is our self-developed Fuel Assist Circuit and Air Assist Circuit. This system not only fully simulates the pilot circuit behavior of a traditional carburetor, but also provides an additional cold-start fuel enrichment effect for easier and more stable cold starts. By independently controlling fuel and airflow in the low-throttle range, GEN3+ delivers extremely precise and linear fuel supply during idle, low throttle openings, and instant throttle transitions. Compared to traditional single-circuit metering rod systems, this design makes idle tuning much easier, improves low-end throttle response, and significantly reduces tuning difficulties caused by altitude, temperature, and humidity changes. Whether during cold starts, technical hard enduro sections, or constantly changing throttle conditions, GEN3+ provides smoother, more controllable, and torque-rich power delivery.

GEN3+ also supports both Single Circuit and Multi-Circuit operating modes, allowing riders to freely switch, combine, and fine-tune the fuel system according to engine characteristics, riding style, and performance goals. Single Circuit mode offers a direct and simplified tuning experience similar to traditional SmartCarb-style systems, while Multi-Circuit mode allows different throttle positions to have more independent and precise fuel control. This results in stronger low-end torque, smoother power transition, and improved high-RPM performance. The ability to freely combine these operating modes makes GEN3+ far more than a conventional carburetor — it becomes a highly adaptable variable fuel control platform.

GEN3+ features a 100% tool-free adjustment system, allowing riders to adjust metering rod height, fuel assist circuits, and bowl fuel release using only two fingers. In addition, optional features such as Power Jet, TPS compatibility, and the Torque Gain System allow the carburetor to be further optimized for different engines and riding styles. Whether riding hard enduro, motocross, woods trails, desert terrain, or high-altitude environments, GEN3+ is designed to deliver stable performance, strong torque output, crisp throttle feel, and reliable fuel control without constant rejetting.

For four-stroke engines, we recommend using premium high-octane gasoline (typically 91 octane or higher) to ensure stable ignition quality and consistent engine operation.

When using ethanol-blended fuels such as E10, E15, or gasoline blends similar to E27–E30 commonly found in Brazil, the carburetor will usually need to be tuned slightly richer to compensate for the characteristics of ethanol fuel. This helps achieve more stable power delivery and better overall engine performance.

2. What is included in the XTNG carburetor kit? Do I need to purchase anything else after receiving it?
A: The XTNG carburetor kit includes all of the essential components required for basic installation and operation, including:

• 1 × XTNG Carb
• 1 × Throttle Cable
• 1 × Fuel Hose
• 1 × High-Quality Fuel Filter
• 4 × Nylon Zip Ties
• 2 × XTNG Stickers
• 1 × Replacement Long Air Screw
• 1 × User Manual

This package is sufficient for basic installation and use on most applications.

If you would like to further improve performance and throttle feel, we recommend selecting our recommended throttle assembly at the time of ordering. For two-stroke applications, we also recommend upgrading the reed valve system.

On some motorcycles, especially certain Chinese-made models and some 1990s Japanese two-stroke models, the OEM reed petals are relatively stiff. This can negatively affect fine fueling control at low throttle openings, often forcing the user to raise the idle setting higher than ideal. As a result, throttle slide opening may exceed the preferred 2–2.5 mm range, which can increase fuel consumption and reduce overall riding range. Upgrading to high-quality reed petals can significantly improve low-RPM throttle response and tuning accuracy.

It is important to note that reed valves are a critical engine component. We strongly recommend purchasing them only through official channels or reputable major distributors. There are many low-quality and counterfeit products on the market, especially from low-grade Chinese sources. These products not only offer poor performance and durability, but may also crack, fail, or disintegrate, potentially causing serious engine damage.

3. Is installation difficult? Can an average user install it by themselves?
A: For most users, installation is not particularly difficult and can usually be completed without major issues. However, fitment conditions vary depending on the motorcycle, especially in terms of intake boot shape, available mounting space, and throttle cable length.

On some models, it may be necessary to slightly trim or relieve the intake boot opening so that the two upper-side intake ports on the carburetor inlet are fully exposed inside the manifold interface.

Each carburetor kit includes, free of charge, a new throttle cable approximately one inch longer than a standard cable. During installation, this cable must be routed through the gap on the left side of the triple clamp, then guided along the left side of the frame to the carburetor. It must not be routed with excessive bends, pinched under the fuel tank, or subjected to any other physical interference, otherwise sticking or drag may occur.

As long as the installation is performed correctly and the throttle cable routing is kept as smooth as possible, most users should be able to complete the installation successfully. However, if you do not have enough experience to ensure proper fitment and function, we recommend having the carburetor installed by a qualified technician or professional mechanic.

4. Can I use the OEM throttle cable with the XTNG carburetor?
A: Every carburetor is supplied with a brand-new throttle cable from the factory, and this cable is compatible with the vast majority of models.

When placing an order, please make sure to select the correct thread size for the throttle cable fitting, which is usually either M10 or M8. This can be confirmed by measuring the thread size of the original throttle cable fitting on your motorcycle.

If you prefer to continue using the OEM throttle cable, you must verify its functionality during installation. After connecting the carburetor, throttle cable, and throttle assembly—but before installing the carburetor on the bike—check whether the throttle slide fully closes when the throttle is released, and whether it can achieve 100% full opening at wide open throttle. If both of these functions work correctly, then the OEM throttle cable can be used properly with the carburetor.

Even in that case, we still recommend using the included new throttle cable whenever possible, because it is more precisely matched to the carburetor and generally provides a smoother, more reliable, and more consistent throttle feel.

5. Is the XTNG carburetor truly plug-and-play? Will it still need adjustment after installation?
A: We do our best to provide a baseline setup that is as close as possible to ride-ready, based on the specific model, application, and configuration. On an engine that is in good mechanical condition, the carburetor will usually run properly immediately after installation.

However, because factors such as engine health, modification level, fuel quality, and environmental conditions vary from one motorcycle to another, a small amount of fine-tuning may still be required to achieve the best possible performance.

6. Will it require frequent re-tuning after installation?
A: Under normal conditions, frequent re-tuning is not necessary. For everyday riding and typical environmental changes, the carburetor will generally remain stable and operate consistently.

Only when there are significant altitude changes, major temperature swings, changes in fuel type, or changes in the engine’s mechanical condition will a minor adjustment sometimes be needed.

7. How is an XTNG carburetor different from a conventional jet-type carburetor?
A: A conventional jet-type carburetor relies mainly on a fixed combination of components such as the main jet, pilot jet, needle, and clip position to match different operating conditions. Because these circuits usually overlap during transition, the resulting power delivery is often less linear, and the engine can feel as though it has noticeable steps or abrupt transitions in the throttle response.

At the same time, when environmental conditions change and re-tuning becomes necessary, a conventional carburetor usually has to be removed from the motorcycle, disassembled, fitted with different main or pilot metering components, or adjusted by changing the needle specification or clip position, and then reinstalled for testing. On many four-stroke motorcycles, limited space around the frame makes this process especially difficult, time-consuming, and labor-intensive. Before the next test ride, the rider still cannot know whether the latest adjustment is truly correct, so repeated removal and repeated test riding are often unavoidable. This not only consumes a great deal of time and effort, but can also lead to unnecessary wear on certain parts.

By comparison, a metering-rod carburetor such as XTNG controls fuel through a fundamentally different metering structure and external adjustment method. As a result, power delivery is more linear, transition is smoother, and the engine response is far less abrupt. At the same time, it offers better environmental adaptability, higher tuning efficiency, and a broader effective operating range. In many cases, the rider does not even need to get off the bike—adjustments can be made in just a few seconds simply by reaching down while seated on the motorcycle.

8. Why can a metering-rod carburetor like XTNG offer better environmental adaptability and performance than a conventional carburetor? What is the underlying principle?
A: To answer this properly, it is first necessary to understand that the operating efficiency of any healthy engine is primarily influenced by two key factors:

the first is the effective air volume entering the engine per unit of time, and the second is the atomization quality of the fuel, meaning how fine the fuel droplets are and how thoroughly and evenly they mix with the incoming air.

All carburetors fundamentally operate on the Venturi effect. As air flows at high speed through the venturi, local pressure drops and creates a vacuum signal that draws fuel from the float bowl into the airstream, where it is atomized by the high-velocity airflow. A conventional jet-type carburetor follows this same principle, but its fuel metering is mainly controlled by the main jet, pilot jet, tapered needle, and their related passages. Because these components and fuel paths do not provide an ideal linear metering geometry, the fuel often has to pass through a passage structure that changes from large to small and then back to large again. This reduces flow continuity and response speed, makes the system more sensitive to changes in venturi signal, and can negatively affect both fuel delivery stability and atomization quality. At the same time, the conventional tapered needle offers only limited ability to guide and disperse the fuel at the moment of discharge, so the resulting fuel droplets are usually larger and the atomization is often less complete.

By contrast, a metering-rod carburetor like XTNG uses a precision-matched metering rod and main fuel tube assembly as its primary fuel metering structure. As the metering rod moves vertically, the effective flow area formed between the rod and the main fuel discharge tube changes in a much more linear manner. Throughout the entire fuel delivery process, the flow path maintains a continuous characteristic of gradually contracting from a larger effective cross-sectional area to a smaller one, without the abrupt geometric transition commonly found in conventional carburetors, where the path effectively goes large-small-large. Because of this, when venturi vacuum acts on the fuel, the response is more direct, smoother, and more immediate.

At the same time, the flat face of the metering rod is oriented toward the engine side. When fuel exits the main fuel tube, it is discharged in a more concentrated direction toward the engine. This flat section of the rod is positioned precisely in the region of strong vacuum created by the high-speed airflow, which significantly strengthens the fuel pickup signal. This effect is a practical expression of Bernoulli’s principle. Under this physical condition, once the fuel enters the venturi, it is subjected to stronger and finer air shear, which breaks the fuel into much smaller droplets and improves atomization quality substantially. The end result is finer fuel particle size, better atomization, and more complete air-fuel mixing.

For these reasons, a metering-rod carburetor has two clear advantages over a conventional carburetor:

First, the fuel delivery process is more linear, more stable, and faster to respond.
Second, fuel atomization is finer and combustion is more complete.

These two core advantages are exactly why XTNG can maintain better mixture quality and more stable combustion efficiency even when external conditions such as altitude, temperature, and humidity change. This is what gives it stronger environmental adaptability, higher operating efficiency, and better overall power delivery. That is also the fundamental reason why an XTNG metering-rod carburetor can be so clearly distinguished from a traditional jet-type carburetor in real-world use.

9. Which of these carburetors delivers the best overall performance: XTNG NEW GEN2 / GEN3+, SmartCarb SC3, Lectron Billetron Pro / H-Series EVO, or the Keihin STIC metering block system?
A: All three belong to the category of metering-rod carburetors, but their design priorities are not the same.

First, looking at the XTNG NEW GEN2, its overall structural concept is closer to the Lectron Billetron Pro. Its core fuel metering strategy is likewise based on a metering rod system that controls the primary fuel delivery. However, compared with the Billetron Pro, the advantage of the XTNG NEW GEN2 is that it not only retains the inherent linear fuel delivery characteristics of the metering-rod system itself, but also incorporates our unique fuel assist circuit and air assist circuit.

This means that in the idle range, small throttle openings, and low-RPM load zone, the XTNG NEW GEN2 no longer relies solely on the metering rod profile to cover all operating conditions. Instead, it can optimize mixture quality in this range more directly and more precisely, much like the pilot system of a conventional carburetor. The end result is a clear advantage in idle stability, low-throttle response, low-end torque output, and overall tuning range.

By comparison, the XTNG GEN3+ can be understood as a hybrid system that combines the respective strengths of the SmartCarb SC3 and the Lectron Billetron Pro, whereas the NEW GEN2, in terms of design philosophy, is structurally closer to the Lectron Billetron Pro. In single-circuit mode, the operating logic and performance characteristics of the GEN3+ can be directly benchmarked against the SmartCarb SC3.From a structural standpoint, both the XTNG GEN3+ and the SmartCarb SC2/SC3 use a venturi design based on a known public-domain concept disclosed in patent CN200971812Y. This venturi adopts an “inverted teardrop” profile, formed by the smooth transitional blending of two circular sections with different diameters. The primary purpose of this design is to strengthen the fuel pickup signal at small throttle openings, thereby improving throttle response and power delivery at low RPM.Compared with the SC2, the main refinement introduced in the SC3 is a further increase in the distance between the centers of the two circular sections. As the throttle opens, this extends the effective working travel of the smaller-diameter section, which in theory prolongs and amplifies the fuel signal in the low-throttle range, thereby improving low-end torque output. However, in practical application, the performance gain in low-RPM torque achieved through this type of purely geometry-based optimization remains relatively limited.By contrast, when the GEN3+ operates in multi-circuit mode, its fuel assist circuit uses a continuously variable adjustment design, allowing the fuel volume delivered in the low-throttle range to be controlled directly and precisely. This active adjustment method no longer depends on passive optimization through venturi geometry alone. As a result, improvements in low-RPM torque are more direct, more effective, and accompanied by a wider adjustment range as well as stronger environmental adaptability.More importantly, the GEN3+ does not only feature an externally adjustable metering rod system. It also incorporates an internally vented pressurized fuel system, a multi-circuit structure, an air circuit selector, a fuel assist circuit, and an air assist circuit, allowing it to combine operational simplicity with highly refined fuel control.

There is also an important structural point that must be clearly stated: on the XTNG GEN3+, the actual venturi size is exactly the same as the nominal size. For example, the 38mm version has a true 38mm venturi bore. By comparison, the Lectron H-Series EVO 38 and Lectron Billetron Pro 38, in order to strengthen the fuel pickup signal and increase local air velocity at low RPM, use an actual venturi diameter of approximately 34mm. That type of design can provide some benefit at low throttle openings, but in terms of theoretical airflow capacity and real peak horsepower potential, it does not match a carburetor with a true 38mm venturi bore.

Both the GEN2 and GEN3+ series have also been fully developed and matched for four-stroke applications. Four-stroke engines demand extremely high fuel control accuracy, especially at idle, where the required air-fuel ratio stability and precision are especially strict. This directly tests whether the carburetor’s structural design is rational and whether its fuel-air mixture control is sufficiently refined.

In real-world operation, XTNG can provide a very stable idle on four-stroke engines, and after sustained high-RPM operation, the engine speed can return quickly and cleanly to normal idle speed. Because XTNG uses a fuel assist circuit that fully simulates the pilot-circuit function of a conventional carburetor, mixture control in the low-throttle range—from idle to approximately one-third throttle—is much more precise. This allows the carburetor to maintain strong performance while also delivering better fuel efficiency and longer riding range.

Compared with the SmartCarb SC3, XTNG shows stronger performance in idle stability, throttle response, and the speed and cleanliness of RPM drop-back to idle in four-stroke applications.

In recent years, a system known as the Keihin STIC Metering Block has gained attention among some high-performance two-stroke riders. Typically used with Keihin PWK carburetors, the core concept of the STIC system is to introduce additional emulsion ports and air-assist passages into the main fuel circuit, allowing air to pre-mix with the fuel before it enters the venturi. This improves fuel atomization and enhances combustion efficiency at high RPM.

Based on our own testing, the STIC system delivers very impressive peak horsepower and significantly stronger top-end performance. However, this aggressive high-RPM-focused design also changes the engine’s power character. The transition from low RPM to mid and high RPM becomes extremely sharp and aggressive, making precise throttle control more difficult in technical riding, hard enduro, and low-traction conditions. Power delivery often feels less linear and less controllable.

At the same time, the STIC system typically recommends larger carburetor sizes and richer jetting configurations to further maximize high-RPM performance. While this “large bore + aggressive emulsification” combination can produce excellent peak power, it also reduces low-RPM air velocity and vacuum signal strength, often resulting in weaker low-end torque, reduced low-throttle response, and a less natural power transition.

For riders focused primarily on maximum peak horsepower and aggressive high-RPM performance, the STIC system can be very effective. However, for riders who prioritize low-end torque, smooth power delivery, and precise technical riding control, a more progressive and balanced fuel metering system will usually provide a superior real-world riding experience.

Comprehensive Performance Test Comparison: XTNG GEN3+, SmartCarb, Billetron Pro, Keihin PWK, JD Jetting, and STIC!

If we look at the final result, the main strengths of XTNG can be summarized in three key points:

First, its ability to optimize the low-throttle and low-RPM range is significantly stronger than that of a typical single-circuit metering-rod carburetor.

Second, the user can choose between a SmartCarb-like simplified operating mode and a tuning capability that approaches or even exceeds Lectron-style multi-zone adjustability.
Third, even with its more complete feature set and greater expansion capability, XTNG still maintains excellent value for money.

In other words, the GEN3+ combines the advantages of all competing systems.

10. What is the difference between single-circuit and multi-circuit operation?
A: Our carburetors can be switched freely between single-circuit and multi-circuit operation. In single-circuit mode, the basic operating logic is essentially the same as that of carburetors such as the SmartCarb SC2 / SC3. This mode is well suited for users who want installation, operation, and baseline tuning to be as simple and straightforward as possible. Its advantages are a direct working structure, simple operation, and performance that is sufficient for general use.

However, the limitations of a single-circuit system are also obvious. Because fuel delivery across all operating conditions is handled mainly by a single metering strategy, the fuel requirements of different throttle positions and different load states cannot be addressed independently. As a result, when a user wants to optimize idle, low RPM, midrange, and high RPM more precisely, the available tuning window becomes clearly restricted. This is especially true on four-stroke engines, where a single-circuit structure often struggles to simultaneously provide stable idle, strong low-throttle response, and clean high-load output.

By contrast, a multi-circuit structure is more similar in concept to the Lectron Billetron Pro series. It allows the fuel requirements of different operating conditions to be handled separately, so that each throttle zone can have more independent and more precise control. This greatly reduces the typical compromise of improving low-end performance at the expense of top-end performance, or vice versa.

In addition, our carburetors also feature a unique air circuit selector, allowing the user to choose whether the air circuit is open or closed according to tuning needs. When the air circuit is opened, fuel atomization in the idle and low-throttle range can be improved significantly, making the mixture in that area more homogeneous and more stable. The direct result is more stable idle quality, along with stronger low-RPM torque output at small throttle openings.

For this reason, in most cases—whether for two-stroke or four-stroke engines—we recommend that users tune and optimize performance in multi-circuit mode, because it provides a wider tuning window, better adaptability, and more complete overall performance.

11. If my bike originally uses a TPS system and a solenoid-controlled Power Jet system, or if it runs a third-party ECU that supports TPS input, do I need to add TPS and transplant the solenoid system to the XTNG carburetor?
A: In original Japanese Keihin and Mikuni carburetor systems, the primary function of the TPS (Throttle Position Sensor) is to send a throttle-opening signal to the CDI or ECU for ignition control and load calculation. The solenoid valve, as an actuator, is normally controlled by the CDI or ECU based on a combination of parameters such as throttle position (TPS) and engine speed (RPM). In other words, the solenoid valve does not operate solely from TPS input; it is part of the complete electronic control strategy.

On some Honda models, the TPS signal does indeed participate in the solenoid control logic, but in essence the system is still managed by the CDI or ECU as a whole, rather than the TPS directly driving the solenoid valve.

Based on this principle, TPS is fundamentally a functional signal-input component. It does not directly increase carburetor performance or engine output. Therefore, whether TPS is needed depends on whether your motorcycle, CDI, or ECU actually relies on that signal. For example, on some models such as Beta, the oil pump system requires a TPS signal in order to function correctly. Likewise, if you want to transplant the OEM carburetor’s solenoid-controlled system in parallel, then TPS is also required. In those cases, TPS has real functional necessity.

From a practical riding standpoint, whether TPS is installed or not has extremely limited influence on the actual performance of a metering-rod carburetor. The difference is almost impossible to feel, and this remains true even when comparing OEM Keihin or Mikuni carburetors with and without TPS connected. Therefore, if your system does not depend on TPS input, there is no need to add unnecessary cost. If, however, you want to preserve complete original functionality or pursue every possible detail, you may choose to install the TPS system.

12. Do I need to install a Power Jet circuit or a torque-enhancement circuit on the GEN3+ carburetor?
A: On the XTNG GEN3+ series, we offer both the Power Jet circuit and the torque-enhancement circuit as optional configurations, but they are not mandatory. Whether they are needed depends entirely on your intended application and riding requirements.

The main function of the Power Jet circuit is to provide additional fuel under high-load or prolonged wide-open-throttle conditions, helping the engine run cooler and improving operating safety. In some specific applications, it can also provide a certain amount of performance optimization. Therefore, if your riding includes straight-line acceleration, long-distance desert riding, or extended wide-open-throttle operation in snow or other extreme conditions, it is worth considering. For normal trail riding, enduro use, or motocross applications, however, it is generally not necessary.

The torque-enhancement circuit can be understood as an auxiliary fuel circuit for the low-RPM range, similar in concept to a low-positioned Power Jet. It may be worth considering when using high-ethanol fuel, or when you want a wider tuning range and greater access to the engine’s performance limit.

That said, it is important to emphasize that even without these optional circuits, the GEN3+ already includes a fuel assist circuit and a pressurized fuel system, both of which can significantly improve low-end torque and throttle response, while still delivering excellent peak power at wide-open throttle. For that reason, most users can already achieve outstanding all-around performance with the standard configuration. Whether to install any additional circuit should be determined entirely by your actual needs and riding habits.

13. If I later find that the setup is not ideal, can I change the metering rod or receive technical support?
A: For the original purchaser, if testing and tuning show that the current metering rod cannot deliver the expected result, we do support metering rod replacement. The rod must remain in good condition, with no physical damage, unauthorized grinding or modification, and no obvious corrosion.

As long as those conditions are met, the user only needs to return the original metering rod to us, and we can replace it with another model or a rod with a different fuel curve according to the actual requirement.

In addition to metering rod replacement service, we also continue to provide follow-up tuning support and technical guidance. Users can contact us by email, and we will assist step by step based on the actual application, helping to optimize the setup until the desired performance is achieved.

14. For two-stroke users, what oil and premix ratio do you recommend?
A: We first recommend that users consult the owner’s manual for their specific motorcycle and follow the factory-specified oil type and premix ratio whenever possible.

In terms of oil selection, we recommend using products from well-known brands with stable and proven quality. For metering-rod carburetors such as XTNG, we generally recommend choosing an oil with a relatively lower flash point whenever possible, especially in cold, damp, or near-freezing conditions, where this becomes even more important.

The reason is that in low-temperature environments, condensation can sometimes form inside the carburetor. When this moisture mixes with an oil that has a higher flash point and higher viscosity, it can create an emulsification effect, which increases friction inside the throttle slide assembly and may cause the slide to move less freely.

To minimize this risk, we recommend that users prioritize high-quality oils from major brands with relatively low flash points, and strictly follow the premix ratio specified by both the oil manufacturer and the motorcycle manufacturer. If the motorcycle is equipped with an oil injection pump system, we likewise recommend choosing a high-quality low-flash-point oil that is specifically suitable for oil-injection applications.

15. Tariffs and Duty Information.
A: XTNG offers worldwide shipping service. Customs duty handling varies depending on the destination region:

For the United States and the European Union, when conditions allow, customs clearance and duty handling are usually managed by our logistics partners, and most customers do not need to pay additional import duties.

For other countries and regions, customs duties, VAT, or clearance fees may apply depending on local customs regulations, and these charges are usually the responsibility of the customer.

If needed, we can provide low-value declarations upon request to help reduce potential tax exposure, but the final outcome still depends on local customs regulations.

XTNG Satisfaction Guarantee

We don’t just deliver products—we stand behind real-world performance. Built on extensive real-world riding tests and continuous technical refinement, XTNG provides a clear and practical support system for every user.

Performance Guarantee

Under the condition that the engine is mechanically sound and the carburetor is properly installed, the XTNG carburetor delivers a significant upgrade in overall performance, providing smoother and more linear power delivery, highly stable idle characteristics, and more precise, efficient fuel control.

For enduro and technical trail riding, XTNG demonstrates clear advantages. Its exceptional low-RPM torque allows the engine to maintain strong drive even at extremely low engine speeds—down to below 1000 RPM. In demanding terrain such as tight woods or steep climbs, riders can confidently use higher gears, improving both control and riding efficiency. For this reason, many users describe their bikes equipped with XTNG as “a tractor in the woods.” In terms of low-end torque, it outperforms even a finely tuned PWK system.

At the same time, XTNG offers an exceptionally smooth and linear power transition, making throttle control more predictable and precise. In the mid-to-high RPM range, it continues to deliver impressive peak power, achieving a well-balanced combination of strong low-end torque and powerful top-end performance.

In four-stroke applications, XTNG consistently surpasses traditional high-performance carburetors such as the FCR in throttle response, idle stability, and peak horsepower output. Additionally, its efficient fuel metering provides noticeably extended range during long-distance riding.

Finally, we provide ongoing professional technical support to ensure that every user can fully unlock the performance potential of the XTNG carburetor and achieve optimal results in real-world riding conditions.

30-Day Return Guarantee

Within 30 days of delivery, eligible products may be returned under our policy. Unused products qualify for a full refund (excluding shipping), while installed but undamaged products may be returned subject to inspection. We want users to make decisions based on real-world experience—not unnecessary risk.

Lifetime Technical Support / Limited Lifetime Warranty