Mikuni Bs26 | Carburetor Manual Verified

Use a properly sized screwdriver to avoid stripping the brass. Remove the main jet, pilot jet, and needle seat.

A long, open-ended rubber hose coming from the upper body. It must remain open to atmospheric pressure and be routed downward toward the ground, away from hot exhaust pipes.

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

Hold the carburetor body at roughly a 60-degree angle. The float tab should just touch the spring-loaded pin of the needle valve without compressing it. mikuni bs26 carburetor manual verified

The entry point for fuel into the bowl. Contains a rubber tip prone to wear.

Remove the jet needle from inside the slide, noting the order of any washers or spacers. Step 3: Float Bowl and Jet Disassembly (Bottom Section)

The Mikuni BS26 carburetor consists of several key components, including: Use a properly sized screwdriver to avoid stripping

Turn the pilot screw clockwise until it gently seats. Do not overtighten, as this will damage the brass tip and the aluminum seat. Back the screw out as a baseline starting point. Warm the engine to operating temperature.

Now that your BS26 is fully disassembled, the actual cleaning can begin. The rubber components must be handled separately to avoid permanent damage.

The float height on most GN250/BS26 applications is roughly 14.6 mm ± 1 mm (always check your specific service manual to be sure). B. Pilot Screw Adjustment (Air/Fuel Ratio) The pilot screw controls the idle mixture. It must remain open to atmospheric pressure and

Tap out the small pivot pin holding the plastic or brass float. Remove the float and the attached needle valve (float valve). Inspect the rubber tip of the needle valve; if it has a grooved ring or is stiff, replace it.

Periodic cleaning is vital as ethanol-blended fuels can clog the tiny orifices of the pilot jet. Mikuni Bs 26 Manual - MCHIP

The BS26 operates on a variable venturi design where a vacuum-operated diaphragm controls the slide lift, ensuring smooth throttle response across various engine speeds. Most tuning issues originate in one of five metering systems:

Proper maintenance requires specific tools and a systematic approach to avoid damaging internal brass components. Verified Tool List: JIS (#2 & #3) Screwdrivers: