Carburetor MXT RACING 17.5mm PHBN complete with manual choke compatible with Minarelli horizontal Aprilia SR 50 Yamaha Aerox CPI

The MXT RACING carburetor in 17.5 mm version is a round slide carburetor of type PHBN with a manual choke. It is designed for horizontal Minarelli engines and is particularly suitable as a replacement solution when a PHBN carburetor is already installed. The factory basic tuning forms the basis for a vehicle-specific fine tuning via the main jet.

Product features:

• Round slide carburetor in 17.5 mm version
• Carburetor type PHBN with manual choke
• Factory basic tuning
• Fine tuning via the main jet
• Suitable for direct replacement where a PHBN carburetor is present
• Connections for gasoline, oil, vacuum and overflows
• Designed for horizontal Minarelli engines
• OEM reference number for comparison: 3067

The design allows for the replacement of an existing PHBN carburetor without a change in concept, as the connections and design are calibrated for continued use of the existing peripherals. For stable engine operation, the correct main jet tuning is crucial, as it significantly determines the fuel quantity in the upper load range.

Technical details:

• Type: round slide carburetor
• Nominal diameter: 17.5 mm
• Carburetor type: PHBN
• Choke: manual
• Connections: gasoline, oil, vacuum, overflows
• Reference number: 3067

The technical specifications serve for the clear assignment within the PHBN design. For compatibility, the carburetor intake, intake manifold and the type of choke actuation are particularly relevant in addition to the nominal diameter.

Vehicle and model compatibility:

• Minarelli horizontal
• Aprilia SR 50
• Yamaha Aerox
• CPI

The actual suitability depends on the installed carburetor intake, the intake manifold as well as the cable and choke routing. Crucial is whether a suitable PHBN intake is present and that the connections fit the vehicle setup.

Installation and application notes:

• Replacement with existing PHBN carburetor without a change in design possible
• Check choke cable and cable routing before installation
• Correctly lay out connections for gasoline, oil, vacuum, and overflows
• After installation, adjust main jet to cylinder, air filter, and exhaust
• Check engine operation after tuning for clean idle and throttle response

The main jet influences the mixture preparation, especially in the upper load range. A clean tuning is necessary to ensure uniform engine operation, controlled temperatures, and a consistently stable operation.

Tuning note main jet - separate orientation:

The following information serves exclusively as a non-binding guideline for the pre-selection of M6 main jets. They do not replace individual tuning on the vehicle.

• 50 cc cylinder, air filter and exhaust original: M6 Set 1 with jet range 50 to 72
• 50 cc cylinder and air filter original: M6 Set 2 with jet range 70 to 92
• 50 cc cylinder with sport or racing air filter: M6 Set 3 with jet range 80 to 102
• 70 cc cylinder with original air filter: M6 Set 3 with jet range 80 to 102
• 70 cc cylinder with sport or racing air filter: M6 Set 4 with jet range 88 to 110

These ranges illustrate that the jet demand shifts with increasing air quantity and cylinder output. Deviations are possible depending on the cylinder condition, exhaust system, and intake system, and must be determined through test rides and spark plug reading checks.

Note on inspection before purchase:

• Before purchase, check whether a PHBN carburetor or a suitable PHBN intake is present on the vehicle. Additionally, the intake manifold, choke design, and required connections should be matched with the existing setup, as compatibility is not solely secured by model designations.

Brief information: Carburetor - Installation, Adjustment & Tuning

Installation: Mount carburetor under no tension, check intake manifold and gaskets for air leaks, adjust throttle cable to ensure smooth operation, ensure fuel supply (gasoline, oil, and vacuum).

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

Tuning:

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

Control: Check spark plug condition

• 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 private label 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 variomatic components, fairing parts, and batteries. The products impress with solid workmanship, accurate quality, and a strong price-performance ratio.

Ideal for riders looking for durable replacement parts and tuning parts for many vehicle models.