Usually a vacuum leak, worn diaphragms, or incorrect synchronization. Where to Find Genuine Parts & Manuals

Hold jets up to light; if you cannot see through them, they are clogged. Clean with wire or replace.

Spray all passages and jets with carburetor cleaner. Use compressed air to blow out passages. Do not use wire in the jets as this can damage the orifices.

Remove the top screws to access the diaphragm and slide. Handle with care ; these are delicate. 4. Cleaning and Inspection

If you're unable to find a service manual, you can try searching for specific repair guides or tutorials on YouTube or other online resources. Additionally, you can consult with a small engine mechanic or a motorcycle repair expert familiar with Mikuni carburetors.

Remove the top cap (4 screws). Carefully lift out the vacuum piston/diaphragm assembly. Do not use solvent on the diaphragm. Use only soapy water. Soak the metal body in carb cleaner for 4 hours, but remove all rubber first.

The is a constant-velocity (CV) downdraft carburetor commonly used on V-twin motorcycles, most notably the Yamaha XV250 Virago (and its V-Star 250 successor) and the Hyosung GV250 . While there is no single standalone "service manual" authored solely by Mikuni for this specific model, comprehensive maintenance data is found within the vehicle-specific service manuals for these motorcycles. Technical Specifications

Once the Mikuni BDS26 is reinstalled on your vehicle, use this matrix to diagnose lingering performance issues: Probable Cause Corrective Action Torn coasting enricher diaphragm or lean pilot circuit.

The is a 26mm downdraft, vacuum-piston (CV) carburetor designed to offer smooth acceleration and consistent fuel management. Proper maintenance is critical for performance, as these units can suffer from clogging due to ethanol-mixed fuels.