Mikuni Bs26 Carburetor Manual Verified Upd -

A thick brass or plastic T-fitting located between the carburetor body (if dual) or on the side. Connects directly to the fuel tank petcock line.

The rubber diaphragm creates a seal; engine vacuum lifts the slide to regulate airflow.

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.

| | Details / Values | Notes | | :--- | :--- | :--- | | Type | Constant Depression (CV), Diaphragm-type, Vacuum-operated | Features a vacuum piston (skep) with a rubber diaphragm. | | Venturi Diameter | 22.2 mm (oval) | Commonly found in BS26-49, BS26-61 and similar variants. | | Identification Number | Stamped on the carburetor body (e.g., BS26-49, BS26-61, BS26SS). | The specific model number identifies its original factory settings. | | Main Jet | Variable; often around #107.5 (varies by model) | Model-specific; e.g., BS26-49 specs list a 107.5 main jet. | | Pilot Jet | Variable; often around #42.5 (varies by model) | Works with the pilot air screw to control idle mixture. | | Float Height | 21.4 mm ± 1 mm | This is the correct specification for the BS26SS variant. | | Idle Speed | 1600 ± 100 RPM | Set after the engine is at full operating temperature. | | Application | Aprilia Leonardo 125 (BS26-49, BS26-61), Suzuki GS-R125, Suzuki RV125 VanVan (2003-06), Suzuki Intruder 125 | Also found on Suzuki AN125/150 Burgman and the Yamaha Byson 125. | mikuni bs26 carburetor manual verified

Remove the float bowl. Inspect for varnish, rust, or debris.

Once inside, the rubber diaphragm is the most critical and fragile component. An inspection requires great care:

The Mikuni BS26 relies on three primary fuel circuits to deliver the correct air-fuel mixture across the entire throttle range. A thick brass or plastic T-fitting located between

I used it specifically for a rebuild on my Suzuki, and the float height settings and pilot screw defaults matched perfectly. It saved me from guessing and potentially ruining a tricky carburetor clean. If you are tuning or rebuilding a BS26, this is the authoritative source you need. Highly recommended for the accuracy alone."

For further assistance or more detailed information, consult the following resources:

Controls fuel delivery from 3/4 to wide-open throttle (WOT). Tap out the small pivot pin holding the

Gently turn the pilot screw clockwise until it lightly seats. Do not overtighten, or you will snap the tip. Back the screw out as a baseline.

Check for "varnish" or green gunk caused by old ethanol fuel.

Carefully lift the cover, noting that the diaphragm spring will push upward.