Main jet blockage or a tear in the diaphragm.
: Use a well-fitting flat-head screwdriver to remove the Main Jet , Pilot Jet , and Needle Jet .
This article serves as a comprehensive guide based on the and industry best practices, covering everything from routine cleaning to a full rebuild. 1. Understanding the Mikuni BDS26
Loosen clamp screws, disconnect throttle cables, choke cable, and fuel hoses. Remove the carburetor unit.
Limit the opening to 3 turns maximum, or it may fall out Kawatriple. Synchronization
October 26, 2023 Subject: Operational Overview, Maintenance Procedures, and Tuning Specifications for Mikuni BDS26 Carburetor Target Application: Small Displacement Motorcycle Engines (typically 125cc–150cc)
Push the emulsion tube out through the top of the carburetor bore (where the slide travels) using a soft wooden dowel.
Essential for preventing flooding or starvation
The Mikuni BDS26 is a dual-body, downdraft constant velocity (CV) carburetor widely used on small-to-medium displacement motorcycles, ATVs, and cruisers—most notably the Yamaha Virago XV250 (V-Star 250). Known for its reliability under optimal conditions, a BDS26 that has sat with modern ethanol fuel will suffer from clogged jets, torn diaphragms, and stiff o-rings.
The following specifications are standard for the Mikuni BDS26 used on 250cc V-twin applications: Specification Idle Speed 1,450 – 1,550 RPM Float Height Main Jet (Front/Rear) Main Air Jet Pilot Jet Jet Needle 2nd groove Throttle Cable Play 0.5 – 1.0mm 2. Essential Maintenance & Cleaning
Understanding the operation is vital for diagnostics:
Check this tiny diaphragm for tears. A ripped deceleration diaphragm causes loud popping in the exhaust when you let off the throttle. 4. Deep Cleaning and Inspection
Keep in mind that working on carburetors requires expertise and patience. Make sure you follow proper safety procedures and take your time when repairing or tuning your Mikuni BDS26 carburetor.
Check the rubber diaphragm for cracks. If stiff or damaged, it must be replaced for the carb to function.