Mikuni Bds26 Service Manual ((full)) -

The Mikuni BDS26 is a 26mm downdraft, constant velocity (CV) carburetor commonly found on multi-cylinder motorcycles like the Yamaha Seca II and the Hyosung GV250. Unlike standard slide carburetors, the BDS26 uses a vacuum-operated diaphragm to control the throttle slide, ensuring smoother throttle response and better fuel atomization across various RPM ranges.

1. Mark each carb body half (left/rear cylinder, right/front). They are matched at factory.
2. Remove vacuum pistons carefully – the diaphragm rubber is irreplaceable.
3. Ultrasonic cleaning allowed only at low heat – high heat warps the zinc-aluminum body.
4. Do not remove the pilot jet if it’s the pressed-in early type. Use carb spray and compressed air only.
5. Accelerator pump nozzle inspection – two small brass squirters aiming into each throat. They clog with ethanol fuel.

Service and Repair Procedures

Tools: Use a high-quality JIS #2 screwdriver for the float bowl screws to prevent stripping. mikuni bds26 service manual

4. Jetting Chart Reference

A typical page in the BDS26 service manual will list: The Mikuni BDS26 is a 26mm downdraft, constant

❌ Using automotive carb cleaner dip

It dissolves the diaphragm rubber and the plastic vacuum piston guide rings. Mark each carb body half (left/rear cylinder, right/front)

Bench Sync: Before installing, ensure both throttle plates open at the exact same time by adjusting the linkage screw.