The Mikuni BS26 is a Constant Velocity (CV) carburetor widely utilized on small-displacement motorcycles and ATVs, most notably the Suzuki GN250 and various Suzuki Intruder 125 models up to 2007. Known for reliability and smooth power delivery, the BS26 relies on vacuum to operate a diaphragm-driven slide.
Prior to disassembly, thoroughly clean the exterior of the carburetor with a dedicated carburetor cleaning spray to prevent dirt from entering the internal passages. 1. Top Cover and Diaphragm Removal Remove the two top cover screws.
The Mikuni BS26 is a robust, well-mannered carburetor when set correctly. trace back to three things: dirty pilot jets, incorrect float height, or a torn diaphragm. Using this verified manual will resolve those issues without guesswork.
Setting the float height is critical to prevent flooding or lean conditions. mikuni bs26 carburetor manual verified
The pilot screw regulates the idle fuel circuit. It is located on the engine side of the carburetor body.
Hold the carburetor body sideways or at a 45-degree angle so the float tang rests lightly against the spring-loaded plunger of the needle valve without compressing it.
A properly tuned BS26 will provide easy starting and smooth operation. A. Float Level Adjustment Turn the carburetor upside down. Measure the distance from the gasket surface to the float. The Mikuni BS26 is a Constant Velocity (CV)
Clean out the needle valve seat. Replace the needle valve if a wear groove appears on its rubber tip. Drop the float in a cup of water to ensure it floats high and does not leak internally.
| Component | Suzuki GSX250 | Kawasaki ZZR250 | Bajaj Pulsar 220 | |-----------|---------------|-----------------|------------------| | | #97.5 | #102 | #115 | | Pilot Jet | #35 | #38 | #40 | | Jet Needle | 5D28 (clip 3rd) | 5C30 (clip 2nd) | 6F24 (clip 3rd) | | Needle Jet | P-2 (O-2) | P-4 (O-4) | P-6 | | Pilot Screw (turns out) | 1.5 – 2.0 | 2.0 – 2.5 | 2.0 | | Float height (mm) | 13.0 ± 1 | 14.5 ± 1 | 12.8 ± 1 |
Standard is 17mm (though this can vary by specific model application). trace back to three things: dirty pilot jets,
If you need help resolving a specific tuning issue with your Mikuni BS26, please share what it is installed on, the current jetting sizes , and the exact performance symptoms you are experiencing.
I used it specifically for a rebuild on my Suzuki, and the float height settings and pilot screw defaults matched perfectly. It saved me from guessing and potentially ruining a tricky carburetor clean. If you are tuning or rebuilding a BS26, this is the authoritative source you need. Highly recommended for the accuracy alone."