Carburetor MXT RACING 21 mm Type PHBG red with 5 mm Main Jet Oil Connection Vacuum Connection

The MXT-RACING carburetor Type PHBG with a 21 mm passage is used for mixture preparation in two-stroke engines and is frequently used in modifications and tuning. The configuration for a 5 mm main jet corresponds to the typical PHBG jetting. A service port on the float chamber facilitates the replacement of the main jet without having to completely disassemble the carburetor for each adjustment.

Product Features:

• Slide carburetor Type PHBG with 21 mm passage
• Designed for 5 mm Main Jet
• Oil connection present
• Vacuum connection present
• Starter operation by cable
• Float chamber made of metal
• Service port on the float chamber for quick main jet replacement
• Color variant red

The equipment is designed for variable installation and clean tuning via the main jet, as the service port can facilitate jet replacement in the installed state. Oil and vacuum connections support integration into setups with separate lubrication or vacuum-controlled fuel supply, provided the vehicle is designed accordingly. The manual starter operated by cable is relevant for the cold start phase and must match the existing operation on the vehicle.

Technical Details:

• Carburetor type: PHBG
• Design: Slide carburetor
• Passage: 21 mm
• Intake manifold connection width: 25 mm
• Air filter connection width: 32 mm
• Air filter connection width with adapter ring: 38 mm
• Main jet: 5 mm version
• Choke: Starter manual by cable
• Connections: Oil connection Vacuum connection Overflows
• Float chamber: Metal
• Color: red

The connection dimensions are crucial for the mechanical fit on the intake manifold and at the air filter connection, while oil and vacuum connections define the technical integration into the respective supply system. The 5 mm main jet determines the jet type used and forms the basis for tuning to the engine and air filter configuration. With the appropriate geometry and a correctly tuned main jet, the mixture preparation can be specifically adapted to modifications.

Vehicle and Model Compatibility:

• Universal use only with a suitable connection geometry and suitable intake system
• Can be used on various two-stroke vehicles, provided the 25 mm intake manifold connection and air filter connection 32 mm or 38 mm with adapter ring fit
• No general assignment to specific models possible, as modifications and different series versions can affect the fit

Assembly and Application Notes:

• Before assembly, the connections for petrol, oil and vacuum on the vehicle must be checked. Starter cable and actuation play must be adjusted before commissioning. The main jet must be tuned to the respective engine and air filter configuration. After installation, idle, throttle response and spark plug image must be checked to avoid malfunctions due to incorrect connection or unsuitable jetting.

A correct connection is functionally relevant, as vacuum and oil connections must be actively used or securely closed depending on the setup to avoid disturbances in the fuel system or air leaks. The main jet tuning influences the mixture preparation under load and is therefore crucial for engine performance and thermal load. Checking the throttle response and spark plug image supports the practical evaluation of whether the jetting matches the configuration.

Note for checking before purchase:

• Before purchasing, the intake manifold connection 25 mm, air filter connection 32 mm or 38 mm with adapter ring, starter operation by cable, as well as oil and vacuum connection on the vehicle must be checked. The carburetor is not vehicle-specific, therefore adjustments may be necessary depending on the setup.

Brief info: Carburetor - Installation, Adjustment & Tuning

Installation: Install the carburetor without stress, check the intake manifold and gaskets for air leaks, adjust the throttle cable smoothly, ensure the fuel supply (petrol, oil and vacuum).

Basic setting: Mixture screw usually open 1.5 - 2.5 turns, adjust the idle screw for a stable idle, always tune the engine when warm.

Tuning:

• Main jet = full throttle / high load
• Needle position = partial load & acceleration
• Pilot jet = idle & starting (usually does not need to be changed)

Check: Check spark plug image

• white = too lean
• black = too rich
• brown = optimal

Important: After changes to the air filter, exhaust or cylinder, a new carburetor tuning is absolutely necessary.

About the manufacturer MXT

MXT is the powerful in-house brand of Heavy Tuned and stands for high-quality replacement and tuning parts for motorcycles, scooters and mopeds.

As a reliable alternative to OEM parts, MXT offers a wide range of cylinder kits, carburetors and crankshafts to variator components, fairing parts and batteries. The products convince with solid workmanship, accurate quality and a strong price-performance ratio.

Ideal for drivers looking for durable spare parts and tuning parts for many vehicle models.