Carefully lift out the rubber vacuum diaphragm and the attached plastic slide.
Controls the needle height based on engine vacuum.
Spray carb cleaner through every hole in the carb body. You should see fluid exiting from another hole. If not, it’s blocked.
The Mikuni BDS26 is a dual-venturi, downdraft constant velocity (CV) carburetor. It is famous for its use on classic V-twin motorcycles like the Yamaha Virago XV250. When properly tuned, this carburetor provides excellent fuel economy and smooth throttle response. However, age, modern ethanol fuels, and extended storage can clog its small internal passages.
Do not use steel wire or drill bits to clean brass jets; steel will enlarge the precise orifices. Use a soft copper wire or dedicated nylon carburetor cleaning brushes.
Turn the pilot mixture screw clockwise while counting the exact number of half-turns until it seats gently.
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.
Because the BDS26 often operates in pairs linked by a throttle shaft, extreme care must be taken to avoid damaging the linkages.
Remove the diaphragm cover, spring, and piston valve assembly. Inspect the diaphragm rubber for rips.
Before beginning, ensure you have a clean workspace and a carburetor rebuild kit containing fresh O-rings, gaskets, and a new needle valve.
For precise fuel level adjustment.
Mikuni BDS26 Service Manual: Complete Overhaul & Tuning Guide 1. Overview of the Mikuni BDS26
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 an in-depth, specific rebuild, refer to the Mikuni PHH Service Manual for general principles and specialized Mikuni Resources for jetting information.
Highly recommended for heavily gummed bodies.
Lift the float out along with the needle valve (float needle). Unscrew the main jet from the center emulsion tube holder.
#110 to #130 (Varies by market/model year) Pilot Jet (Typical factory): #15 to #20 Float Height: 13mm to 14mm Idle RPM: 1,300 – 1,500 RPM Key External Components
Unscrew the main jet located in the center of the mixing tower.
Carefully lift out the rubber vacuum diaphragm and the attached plastic slide.
Controls the needle height based on engine vacuum.
Spray carb cleaner through every hole in the carb body. You should see fluid exiting from another hole. If not, it’s blocked.
The Mikuni BDS26 is a dual-venturi, downdraft constant velocity (CV) carburetor. It is famous for its use on classic V-twin motorcycles like the Yamaha Virago XV250. When properly tuned, this carburetor provides excellent fuel economy and smooth throttle response. However, age, modern ethanol fuels, and extended storage can clog its small internal passages.
Do not use steel wire or drill bits to clean brass jets; steel will enlarge the precise orifices. Use a soft copper wire or dedicated nylon carburetor cleaning brushes. mikuni bds26 service manual
Turn the pilot mixture screw clockwise while counting the exact number of half-turns until it seats gently.
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.
Because the BDS26 often operates in pairs linked by a throttle shaft, extreme care must be taken to avoid damaging the linkages.
Remove the diaphragm cover, spring, and piston valve assembly. Inspect the diaphragm rubber for rips. Carefully lift out the rubber vacuum diaphragm and
Before beginning, ensure you have a clean workspace and a carburetor rebuild kit containing fresh O-rings, gaskets, and a new needle valve.
For precise fuel level adjustment.
Mikuni BDS26 Service Manual: Complete Overhaul & Tuning Guide 1. Overview of the Mikuni BDS26
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 You should see fluid exiting from another hole
For an in-depth, specific rebuild, refer to the Mikuni PHH Service Manual for general principles and specialized Mikuni Resources for jetting information.
Highly recommended for heavily gummed bodies.
Lift the float out along with the needle valve (float needle). Unscrew the main jet from the center emulsion tube holder.
#110 to #130 (Varies by market/model year) Pilot Jet (Typical factory): #15 to #20 Float Height: 13mm to 14mm Idle RPM: 1,300 – 1,500 RPM Key External Components
Unscrew the main jet located in the center of the mixing tower.
