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.
Proper cleaning is the most important part of the service manual process.
for your specific bike model. Where to buy high-quality, OEM-style rebuild kits .
Carefully seat the diaphragm in its groove before tightening the top cap. 5. Tuning and Setup Once installed, the BDS26 needs to be synchronized.
: For heavy buildup, remove the carburetor and disassemble key components like the float, jets, and needle valve. mikuni bds26 service manual
The Mikuni BDS26 is a constant-velocity (CV), "double" carburetor system commonly found on motorcycles such as the , Yamaha SRV250 Renaissa , and Hyosung GV250
If a jet is completely plugged, slide a single strand of copper wire or a 0.010-inch guitar string through the center hole. Never use hardened steel drill bits or sewing needles, as they will enlarge the soft brass orifice and ruin your jetting calibration.
If you have landed on this page, you are likely staring at a vintage carburetor with “Mikuni BDS26” stamped on the side. Whether it is bolted to a classic Arctic Cat snowmobile, a vintage Yamaha Enticer, or a custom go-kart, one truth remains universal:
Turn the carburetor over and locate the pilot mixture screw (often blocked by a brass plug on US models for emissions). If plugged, carefully drill and pop the plug out. The is a 26mm downdraft, vacuum-piston (CV) carburetor
Usually caused by a worn needle valve or a piece of debris stuck in the seat.
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.
Comprehensive Service Guide for the Mikuni BDS26 Carburetor The Mikuni BDS26 is a dual-venturi, downdraft constant velocity (CV) carburetor. It is widely used in twin-cylinder motorcycles and cruisers, most notably the Yamaha Virago XV250 (V-Star 250). Proper maintenance of this carburetor ensures optimal fuel efficiency, smooth idling, and reliable throttle response.
Use compressed air to blow through every orifice. Do not use wire or drill bits to clean jets, as this can enlarge the precision-drilled holes and ruin the tuning. 3. Critical Specifications for your specific bike model
Gently tap the side of the bowl with a plastic mallet if it is stuck. Do not pry with a flathead screwdriver, or you will mar the sealing surface.
Remove the top cap to inspect the rubber diaphragm. Look for tears, cracks, or hardening. 5. Rebuilding and Reassembly
If you can tell me what you are experiencing (e.g., hard starting, stalling at idle, high speed hesitation), I can provide more specific troubleshooting advice. Alternatively,
Lift the plastic float assembly straight up. The float needle valve (needle seat plunger) will come out hooked to the float tang.
To help tailor this guide to your specific project, let me know: