1. Product Overview
Thank you for choosing the NIBBI PEZ Carburetor. This manual provides essential information for the correct installation, operation, maintenance, and troubleshooting of your new carburetor.
1.1 Key Features
- Outstanding Combustion Efficiency: Advanced technology for thorough fuel combustion, improving fuel efficiency and reducing emissions.
- Precision Air-Fuel Ratio Control: Integrated sensor technology for stable engine operation and enhanced power output.
- Strong Adaptability: Designed for diverse climates and environments globally.
- Durable and Resilient Design: High-quality materials and craftsmanship for long-term reliable performance.
- User-Friendly and Easy Adjustment: Simple to adjust and maintain, even for non-professionals.
- High Compatibility: Excellent compatibility with various automobile types, older or newer models.
- Ultra-Low Failure Rate: Remarkable stability under harsh conditions.
- Precision Manufacturing Process: Rigorous quality control meeting high manufacturing standards.
- Lightweight Design: Advanced lightweight materials improve fuel efficiency and handling.
1.2 Fitment Information
- PEZ 28mm: Can directly replace PZ30 carburetors. Mounting holes and dimensions are identical.
- PEZ 30mm: Can directly replace PZ33 carburetors. Mounting holes and dimensions are identical.
2. Safety Information
Please read all safety instructions carefully before installation and operation.
- High-Precision Product: This is a high-precision processed product. If any work is required on it, ensure it is done in a clean environment.
- Manufacturer Responsibility: Damage to the carburetor during adjustment or disassembly is not covered by the manufacturer's responsibility.
- Environmental Factors: Carburetor function is affected by air pressure, temperature, humidity, and altitude.
- Professional Advice: This carburetor requires knowledge and understanding for its setup. If you lack either, contact a professional for advice.
- No Open Flames: Ensure to stay clear of open flames or sparks to avoid unplanned fires during installation or adjustment.
- Secure Installation: Make sure all screws are tightened properly before starting the engine.
3. Package Contents
Please check the package contents against the list below:
- 1 x NIBBI PEZ Carburetor (28mm or 30mm model)
- 4 x Spare Carburetor Jets
- 2 x NIBBI Stickers
- 1 x Instruction Manual (this document, also available as PDF)
If any items are missing or damaged, please contact your seller.
4. Specifications
4.1 General Specifications
- Item Type: Carburetor
- Material: Aluminum Alloy
- Item Weight: 0.6 kg
- External Testing Certification: CE
4.2 Dimensional Specifications
| Model | Outer Diameter (A) | Inner Diameter (B) | Width (C) | Intake Diameter (D) | Height (E) |
|---|---|---|---|---|---|
| 28mm | 48 mm | 28 mm | 84 mm | 44 mm | 154 mm |
| 30mm | 51 mm | 30 mm | 84 mm | 46 mm | 154 mm |
4.3 Original Jet Settings
| Model | Pilot Jet | Main Jet |
|---|---|---|
| 28mm | #40 | #108 |
| 30mm | #38 | #112 |
4.4 Optional Jet Specifications
The carburetor comes with additional jets for tuning. Refer to the table below for available sizes:
| Jet Type | Available Sizes (28mm) | Available Sizes (30mm) |
|---|---|---|
| Pilot Jet | #30, #32, #35, #36, #38, #40, #42, #45, #48 | #30, #32, #35, #36, #38, #40, #42, #45, #48 |
| Main Jet | #95, #100, #102, #105, #108, #110, #112, #113, #115, #118, #120, #122, #125, #128, #130, #132, #135, #138, #140, #145, #148, #150 | #95, #100, #102, #105, #108, #110, #112, #113, #115, #118, #120, #122, #125, #128, #130, #132, #135, #138, #140, #145, #148, #150 |
5. Setup & Installation
Proper installation is crucial for optimal performance and safety. If you are unsure, seek professional assistance.
5.1 Pre-Installation Checks
- Ensure the engine is cool before starting any work.
- Gather all necessary tools.
- Confirm you have all package contents.
5.2 Installation Steps
- Remove Old Carburetor: Disconnect the fuel line, throttle cable, and any vacuum lines. Unbolt the old carburetor from the manifold and air filter.
- Inspect Manifold: Check the intake manifold for cracks or damage. Ensure the gasket surface is clean.
- Install New Carburetor: Attach the NIBBI PEZ Carburetor to the intake manifold using a new gasket if necessary. Ensure a tight, leak-free seal.
- Connect Air Filter: Securely attach the air filter to the carburetor's air intake.
- Connect Throttle Cable: Route and connect the throttle cable to the carburetor's throttle slide mechanism. Ensure smooth operation without binding.
- Connect Fuel Line: Attach the fuel line to the carburetor's fuel inlet. Ensure the fuel filter (if present) is clean.
- Connect Accelerator/Choke Cable: If applicable, connect the choke cable to the starter system lever on the carburetor.
- Final Tightening: Double-check all bolts, clamps, and connections to ensure they are secure.
5.3 User Installation Tips
- Some users have noted that the left side wall of the carburetor might be thick, requiring careful trimming with an angle grinder for easier nut fitting.
- If the mounting stud appears too long for your application, it can be carefully shortened to a more convenient length.
6. Operation & Tuning
The NIBBI PEZ Carburetor features adjustable components for fine-tuning engine performance. Understanding these components is key to optimal operation.
6.1 Key Adjustable Components
- Idle Speed Screw: Adjusts the engine's idle RPM. Rotating clockwise increases idle speed; counter-clockwise decreases it.
- Air Fuel Mixture Screw: Controls the air-fuel ratio at idle and off-idle. Rotating clockwise reduces air (richer mixture); counter-clockwise increases air (leaner mixture).
- Starter System (Choke): A choke valve designed to restrict airflow, enriching the mixture for cold starts.
- Jet Needle: Controls fuel delivery in the mid-range throttle opening. It has multiple clip positions; moving the clip down (raising the needle) richens the mixture, and moving it up (lowering the needle) leans it.
- Main Jet: Controls fuel delivery at wide-open throttle. A larger number indicates a richer mixture.
- Pilot Jet: Controls fuel delivery at idle and very low throttle openings. A larger number indicates a richer mixture.
6.2 Basic Tuning Common Sense
- Jet Needle: There are five options per needle. The higher the number, the richer the mixture.
- Air Screw: Clockwise rotation leans the mixture; counter-clockwise rotation richens it.
- Main Jet: The bigger the main jet, the richer the fuel.
- Pilot Jet: The bigger the slow jet, the richer the fuel.
- Throttle Valve: The throttle valve opening is inversely proportional to fuel concentration. If the throttle valve is small and the fuel is rich, otherwise the fuel is lean.
6.3 Tuning Notes
- Basic Jetting: Start with the air screw fully in, then turn it out 1.5 turns. If the engine runs too rich or too lean, adjust with the air screw. If this cannot be done within a few turns, change the slow jet.
- Rich Mixture (Closed to Half Throttle): If the mixture is too rich and cannot be rectified with the air adjustment screw, use a smaller slow jet.
- Lean vs. Rich: Running too rich will reduce performance. Running too lean will eventually damage engine components (piston, cylinder, head). Always start on the rich side and work towards the proper setting.
- Spark Plug Reading: This is crucial for assessing your mixture:
- Black or Wet Plug: Mixture is too rich.
- Dry, Grey, or White Plug: Mixture is too lean (dangerous, can cause overheating and damage).
- Brown and Clear Plug: Mixture is correct.
- Change One Factor at a Time: When tuning, change only one component (e.g., main jet) at a time and assess the changes before making further adjustments.
6.4 Natural Environmental Factors
Carburetor settings can be affected by changes in air pressure, temperature, humidity, and altitude. Adjustments may be necessary when operating in different conditions.
7. Maintenance
Regular maintenance ensures the longevity and optimal performance of your NIBBI PEZ Carburetor.
- Keep Clean: Periodically clean the exterior of the carburetor to prevent dirt and debris from entering.
- Fuel Quality: Use clean, fresh fuel. Stale or contaminated fuel can clog jets and passages.
- Fuel Filter: Ensure your fuel system has a clean, functional fuel filter.
- Inspect for Leaks: Regularly check for fuel leaks around the carburetor, fuel lines, and manifold.
- Jet Inspection: If performance issues arise, inspect the main and pilot jets for clogs or damage. Clean them with carburetor cleaner and compressed air (never use wire).
- Air Filter: Maintain a clean air filter to prevent dirt from entering the carburetor and engine.
- Throttle Cable: Ensure the throttle cable operates smoothly and is properly lubricated.
8. Troubleshooting
This section provides common issues and their potential solutions. Always refer to the tuning notes in Section 6 for context.
| Problem | Mixture State | Setting | Notes |
|---|---|---|---|
| When Idling: Engine runs erratic, RPM not stable | Lean | Turn air screw counter-clockwise (richer), or change to bigger slow jet. | Possible broken reed petal or air leak in inlet tract. |
| When Idling: Engine stalls, exhaust fumes black | Rich | Turn air screw clockwise (leaner), or change to smaller slow jet. | |
| When Riding Away: Poor acceleration | Lean | Change to bigger main jet. | |
| When Riding Away: Engine runs erratic (between closed and 1/4 throttle) | Rich | Change to smaller main jet or thinner needle. | |
| Rapid Throttle Opening: Engine stalls | Lean | Turn air screw counter-clockwise (richer). | |
| Rapid Throttle Opening: Engine feels flat | Rich | Change main jet to a smaller one. |
9. User Tips
Insights from other users can help optimize your experience with the NIBBI PEZ Carburetor:
- When installing, some users have found it helpful to carefully trim the thick wall on the left side of the carburetor with an angle grinder to allow easier fitting of nuts.
- If the mounting stud is too long for your specific engine, it can be shortened to a more convenient length.
- The carburetor is noted for its excellent ability to regulate idle speed, making fine-tuning easier.
- The inclusion of extra jets (nozzles) is appreciated for allowing immediate tuning adjustments.
- Some users have successfully modified the carburetor cover in a classic style (similar to PZ30-32) for a very brisk response.
10. Warranty & Support
For warranty information, technical support, or any product-related inquiries, please contact your original point of purchase or the NIBBI official store. Keep your purchase receipt as proof of purchase.
This manual is also available in PDF format for your convenience. Reference: User Manual (PDF)