| JET SIZE | MM | INCHES | NUMBERED DRILL BIT | JET SIZE WHEN DRILLED |
|---|---|---|---|---|
| #66 | .66mm | .02598" | #71 | |
| #68 | .68mm | .02677" | ||
| #70 | .70mm | .02756" | #70 @ .0280" | 71.12 jet |
| #72 | .72mm | .02835" | #69 @ .0292" | 74.2 jet |
| #79 | .79mm | .0312" | 1/32" @ .0312" | 79.2 jet |
| #80 | .80mm | .03150" | #68 @ .0310" | 78.7 jet |
| #83 | .83mm | .03268" | #66 @ .033" | 83.8 jet |
| #89 | .89mm | .035" | #65 @ .035" | 89 jet |
| #91.5 | .915mm | .036" | #64 @ .036" | 91.5 jet |
| #96.5 | .965mm | .038" | #62 @ .038" | 96.5 jet |
| #101.5 | 1.015mm | .040" | #60 | 101.5 jet |
| #105 | 1.05mm | .0415" | #59 @ 1.06mm | 106 jet |
| #110 | 1.10mm | .043" | #57 @ 1.11mm | 111 jet |
| #115 | 1.15mm | .0455" | ||
| #120 | 1.20mm | .047" | #56 @ 1.19mm | 119 jet |
| #125 | 1.25mm | .049" | ||
| #130 | 1.30mm | .051" | #55 @ 1.33mm | 133 jet |
| #135 | 1.35mm | .053" | ||
| #140 | 1.40mm | .055" | #54 @ 1.40mm | 140 jet |
Importance of understanding pilot jet drill size for motorcycle enthusiasts
Contents
Understanding pilot jet drill size is crucial for motorcycle enthusiasts who want to optimize their bike’s performance. The pilot jet is responsible for regulating the air/fuel mixture in the carburetor at low throttle positions, and the drill size of the jet determines the amount of fuel that flows through it.
An incorrect pilot jet drill size can cause various issues, such as:
- Poor idling: If the drill size is too small, the engine may idle poorly, resulting in stalling, hesitation, or rough running.
- Rich or lean conditions: If the drill size is too large or too small, the air/fuel mixture can become too rich or too lean, leading to poor acceleration, reduced power, or even engine damage.
- Fuel efficiency: A properly sized pilot jet can optimize fuel efficiency and help save money on gas.
Motorcycle enthusiasts who want to improve their bike’s performance, fuel efficiency, and overall rideability should understand how to use the Mikuni pilot jet drill size chart. With this knowledge, they can choose the correct pilot jet drill size for their specific bike and riding conditions, ensuring that their motorcycle runs smoothly and efficiently.
Overview of Mikuni carburetors
Mikuni carburetors are a popular choice among motorcycle enthusiasts due to their reliability and performance. They are a type of constant velocity (CV) carburetor that uses a vacuum to maintain a constant air/fuel mixture as the throttle is opened and closed.
Mikuni carburetors have several features that make them desirable for motorcycle enthusiasts, including:
- High-Quality Construction: Mikuni carburetors are well-known for their durable construction and high-quality materials. They are designed to withstand the rigors of daily use and offer excellent performance in a wide range of conditions.
- Versatility: Mikuni carburetors come in a variety of sizes and configurations, making them suitable for use on a broad range of motorcycles and other vehicles.
- Easy Tuning: Mikuni carburetors are designed to be easy to tune, making them an excellent choice for motorcycle enthusiasts who like to make their own adjustments and modifications.
- Availability of Parts: Mikuni carburetors are widely used, and as such, replacement parts and rebuild kits are readily available, making maintenance and repair easy.
Overall, Mikuni carburetors offer a reliable and efficient solution for motorcycle enthusiasts looking to upgrade their bike’s performance. Their combination of durability, versatility, and ease of tuning make them a popular choice among riders of all levels.
The Importance of Pilot Jets in Carburetors and How They Work
Pilot jets are an essential component of a carburetor that regulate the air/fuel mixture at low throttle positions. These small brass jets have tiny holes that control the amount of fuel that flows through them. The air/fuel mixture that is delivered to the engine affects the bike’s performance, fuel efficiency, and emissions.
The function of the pilot jet is to provide the right amount of fuel to the engine during idle and low-speed operation. When the throttle is in the closed position, the pilot jet supplies fuel to the engine, keeping it running smoothly. As the throttle is opened, the pilot jet begins to work in conjunction with the main jet, which controls the air/fuel mixture at higher throttle positions.
The importance of the pilot jet in a carburetor cannot be overstated. A poorly adjusted or incorrect pilot jet can result in issues such as poor idling, reduced power, and reduced fuel efficiency. In extreme cases, an incorrect pilot jet can cause engine damage or even failure.
To ensure that a bike runs smoothly, it is essential to use the right pilot jet size for the bike’s engine and riding conditions. Factors such as altitude, temperature, and modifications to the bike’s air intake or exhaust system can affect the pilot jet’s size requirement. Using a pilot jet that is too large or too small can lead to performance issues and potentially expensive repairs.
In summary, understanding pilot jets’ function in a carburetor is crucial for motorcycle enthusiasts looking to optimize their bike’s performance, fuel efficiency, and emissions. By choosing the right pilot jet size and making necessary adjustments, riders can ensure that their bike runs smoothly and efficiently.
