For the best results, tune the circuits in a specific order. Start with the pilot circuit, then move to the needle, and finish with the main jet.
from a lightly seated position. Fine-tune by finding the highest idle point during engine warmup. Diaphragm Inspection: mikuni bs26 carburetor manual verified
Remove the two top Phillips screws. Hold the cap down firmly while loosening, as there is a compressed spring underneath. Lift off the cap, remove the spring, and gently pull the rubber diaphragm and plastic slide upward. Inspect the rubber diaphragm for pinholes, tears, or hardening. 2. Needle Extraction For the best results, tune the circuits in a specific order
The Mikuni BS26 is a 26mm Constant Velocity (CV) diaphragm carburetor used widely across the powersports industry. Found on engines ranging from 125cc to 250cc, it balances fuel efficiency with reliable throttle response. Fine-tune by finding the highest idle point during
Remove the screws securing the top cap. Hold the cap down firmly, as the internal spring is under tension. Remove the cap, spring, and the plastic spring seat.
Hold the carburetor body sideways so that the float hangs down, resting lightly against the needle valve without compressing the internal tiny spring-loaded pin.
A long, open-ended rubber hose coming from the upper body. It must remain open to atmospheric pressure and be routed downward toward the ground, away from hot exhaust pipes.