Because this carburetor was manufactured under contract by Hitachi (to Mikuni specifications) primarily for Suzuki, standalone "Mikuni" manuals are rare. The "verified" data is found in the official .
14.0mm ± 1.0mm (Measured from the gasket surface without the gasket installed) 2. How the Mikuni BS26 Works
When working on a Mikuni BS26, cleanliness is more important than mechanical strength. Use a high-quality carb cleaner and ensure every tiny passage is verified clear before reinstallation.
If you want to troubleshoot a specific issue with your Mikuni BS26, I can provide the exact steps. Please let me know: The of your vehicle
To properly tune or rebuild a BS26, you must identify its core components: The main housing. Vacuum Diaphragm & Slide: Controls air intake speed. Main Jet: Affects high-speed, wide-open throttle (WOT). mikuni bs26 carburetor manual verified
Standard operating idle is typically between 1,450 and 1,550 RPM once the engine has reached operating temperature. Maintenance and Rebuild Best Practices
: Governs mid-range performance between 1/4 and 3/4 throttle. Main Jet : Dictates fuel flow at wide-open throttle (WOT).
The viton-tipped valve that stops fuel flow when the bowl is full.
The Mikuni BS26 carburetor is a marvel of engineering when it's working correctly, but its design means it won't tolerate neglect or guesswork. "Verified" means more than just reading a blog post—it means cross-referencing information from official OEM service manuals for your specific bike model. Because this carburetor was manufactured under contract by
Start the engine and allow it to reach operating temperature. Use the idle speed screw (the large thumb screw on the throttle linkage) to set the engine idle speed according to your vehicle manual (typically 1,300 to 1,500 RPM). Fine-Tuning the Mixture
If you experience a "flat spot" during mid-range acceleration (1/4 to 3/4 throttle), you may need to adjust the jet needle.
Use specialized carburetor cleaner and compressed air to clear internal passageways. Ensure the tiny orifices in the pilot jet and the holes in the emulsion tube are completely clear.
2.5 turns out from lightly seated. Fine-tuning method: How the Mikuni BS26 Works When working on
| Circuit | Typical BS26 range | GS500 (1996–2000) | |---------|-------------------|--------------------| | Pilot jet | 35 – 45 | 37.5 | | Main jet | 120 – 140 | 125 | | Pilot air jet | 80 – 120 | 95 | | Needle clip position | Groove 1–5 | 3rd from top |
Adjust in 1/4 turn increments while the engine is warm to achieve the highest, smoothest idle. C. Needle Position
Provides an enriched mixture for cold starts. 2. Tuning & Adjustment Specifications
Using a digital caliper, measure the distance from the mixing chamber gasket surface (gasket removed) to the highest point of the float.