Mikuni Bs26 Carburetor Manual Verified

The Mikuni BS26 relies on three primary fuel circuits to deliver the correct air-fuel mixture across the entire throttle range.

Located at the top of the carburetor. It reacts to engine vacuum.

For more information on the Mikuni BS26 carburetor, you can consult the following resources:

Use compressed air to blow out all internal circuits and dry the parts completely. 5. Critical Reassembly and Float Level Verification The Verified Float Height Measurement mikuni bs26 carburetor manual verified

| Specification | Verified Value | Notes | | :--- | :--- | :--- | | | #127.5 (Left) / #130 (Right) | GS500 only. Singles use #125. | | Pilot Jet | #40 | (Some models use #37.5 – check your needle) | | Pilot Air Screw | 2.5 to 3.0 turns out | From fully seated. Do not exceed 4 turns. | | Float Height | 13.0 mm (13.7 mm for GN250) | Measure with carb inverted, float tang just touching needle spring. | | Needle Clip Position | 4th groove from top | (Standard is middle, but GS500 uses richer 4th) | | Idle Speed | 1,200 RPM (+/- 100) | Must be set when engine is fully hot. | | Diaphragm Part # | 13258-02C00 | (OEM Mikuni – Aftermarket fails quickly) | | Float Bowl Gasket | 13269-01A00 | Not reusable after soaking in cleaner. |

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Start the engine and allow it to reach operating temperature. Use the idle speed screw (the large thumb screw on the throttle linkage) to set the engine idle speed according to your vehicle manual (typically 1,300 to 1,500 RPM). Fine-Tuning the Mixture The Mikuni BS26 relies on three primary fuel

The BS26 relies on five primary overlapping circuits to manage the air-fuel mixture between approximately 1,750 and 4,500 RPM Pilot Circuit: Controls idle and low-speed operation. Throttle Valve (Slide): Regulates air intake via vacuum pressure. Needle Jet & Jet Needle: Manages the mid-range mixture (1/4 to 3/4 throttle). Governs high-speed and wide-open throttle (3/4 to 4/4). Choke Circuit: Provides a rich mixture for cold starts. Critical Maintenance & Tuning

Back it out to the initial setting: as a starting point.

Gently grasp the plastic slide and pull upwards. The rubber diaphragm will lift out of its machined groove. Inspect the rubber immediately by holding it up to a light source to check for pinholes or tears. For more information on the Mikuni BS26 carburetor,

Tuning a CV carburetor requires a systematic approach. The air screw should be adjusted for a smooth idle, while the jet needle affects the mid-range. 2.1 Setting the Pilot/Air Screw

If adjustments are necessary, carefully bend the small brass tang on the float arm. Do not press against the delicate needle valve tip while bending.

The Mikuni BS26 carburetor is a vacuum-piston carburetor designed to provide a precise air-fuel mixture to the engine. It features a simple and rugged design, making it easy to maintain and repair. The BS26 carburetor is commonly used in motorcycles, scooters, and ATVs, but it can also be found in other applications such as go-karts and mini-bikes.