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PHBG 21mm Racing Carburetor for 2-Stroke 70cc 90cc Big Bore
PHBG 21mm Racing Carburetor for 2-Stroke 70cc 90cc Big Bore
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Product Overview
Build stronger top-end power with this PHBG 21mm racing carburetor, designed for 70cc–90cc 2-stroke big bore moped, scooter, and racing-style engine setups.
Compared with the 19mm version, the 21mm bore provides more airflow for higher-revving engines and modified cylinders. It is a better choice for riders running a big bore kit, sport exhaust, upgraded intake, or other performance modifications where the engine needs additional fuel and air at higher RPM.
This carburetor is suitable for many RS50, RX50, MX50, SX50-style, MBK 50, and similar 2-stroke platforms with compatible intake and cable setup. Proper jetting and tuning are required for best performance.
Product Compatibility
| Category | Fitment |
|---|---|
| Engine Type | 2-Stroke / 2T engines |
| Engine Range | 70cc–90cc performance and big bore builds |
| Target Vehicles | Mopeds, scooters, mini bikes, small racing platforms |
| Example Platforms | RS50, RX50, MX50, SX50-style, MBK 50 and similar models |
| Best Use | Big bore builds, racing setup, stronger top-end power |
Specifications
| Specification | Details |
|---|---|
| Product Type | PHBG-Style Racing Carburetor |
| Bore Size | 21mm / 0.82" |
| Engine Type | 2-Stroke |
| Recommended Engine Range | 70cc–90cc |
| Material | High-strength alloy |
| Application | Moped / Scooter / Mini Bike / 2T Big Bore Build |
| Condition | New |
Key Features
- 21mm High-Flow Bore – Better suited for 70cc–90cc big bore and racing setups.
- Designed for Top-End Power – Supports higher airflow demand at upper RPM.
- PHBG-Style Adjustment – Allows tuning of idle, needle position, and jetting.
- Improved Air-Fuel Delivery – Helps support smoother acceleration on modified engines.
- Performance Build Ready – Ideal for tuned 2-stroke mopeds, scooters, and mini racing platforms.
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Fitment FAQ
Will this part fit my specific model and year?
This PHBG 21mm carburetor may fit many 70cc–90cc 2-stroke performance builds, including RS50, RX50, MX50, SX50-style, MBK 50, and similar moped or scooter platforms. Fitment is not based on model name alone. Please confirm your intake manifold size, throttle cable, choke style, air filter connection, and available installation space before ordering.
Do I need to match the OEM part number?
No, not necessarily. This is an aftermarket racing carburetor for modified 2-stroke engines, not a direct OEM replacement carburetor. Instead of relying only on an OEM part number, compare the carburetor bore size, mounting side, air filter side, throttle cable connection, choke type, and fuel line layout.
What models or situations does this part not fit?
This 21mm carburetor is not recommended for stock 50cc engines or lightly modified setups that cannot support the added airflow. It may also not fit 4-stroke engines, incompatible intake manifolds, different cable or choke systems, or bikes with limited carburetor clearance. For smaller 50cc–70cc sport setups, the 19mm version may be easier to tune.
What should I check before ordering?
Before ordering, please check your engine displacement, big bore kit size, current carburetor size, intake manifold diameter, air filter connection, throttle cable end, choke type, fuel line position, and installation space. Because this is a performance carburetor, jetting and air-fuel tuning are usually required after installation.