Mikuni Bs25 Carburetor Diagram Patched -

Use a new float bowl packing/gasket (such as Mikuni TM42/05 for some models). 3. Cleaning Key Passages

The BS25 hates ethanol. If you have to patch it, you are fighting corrosion. Buy a new OEM diaphragm kit, clean the carb properly, and install an inline fuel filter. Your scooter will thank you with a cold start on the first kick.

In a perfect world, the Mikuni BS25 routes fuel and air like this: mikuni bs25 carburetor diagram patched

Have you successfully patched a BS25 diaphragm? (We know you tried). Tell us your horror story in the comments below.

The BS25 is a 25mm venturi carburetor (34mm outer intake, 42mm outer air filter side). Accesses the throttle slide and needle. Use a new float bowl packing/gasket (such as

The Mikuni BS25 is a 25mm Constant Velocity (CV) carburetor, frequently found on small-displacement Japanese motorcycles, ATVs, and older scooter models from the 1980s and 1990s. While known for smooth operation, the BS25 is susceptible to issues related to aging rubber components, clogged jets, and vacuum diaphragm failure.

After 20+ years, the rubber diaphragm cracks, the pilot jet clogs, and the gasket between the float bowl and main body swells or shrinks. If you have to patch it, you are fighting corrosion

CV carburetors are hypersensitive to unmetered air leaks. A patched schematic emphasizes three critical sealing points: