Mikuni Bs25 Carburetor Diagram Patched May 2026

The official factory diagram (available in service manuals) shows 47 individual parts. It is a standard exploded view: a center line with the main carb body, parts floating left and right with leader lines to part numbers.

Key components in the original diagram:

Why the original diagram fails:

        [Choke Plunger] ──── [Enrichment Circuit]
                 │
    [Air Horn] ──┼── [Diaphragm Cover] ── [Vacuum Piston / Slide]
                 │           │                     │
    [Air Jet (Primary)] ─────┼───── [Needle Jet] ──┤
                             │                     │
    [Throttle Stop Screw] ──[Throttle Valve]       │
                             │                     │
    [Main Jet] ── [Emulsion Tube] ─────────────────┘
         │                    │
    [Float Bowl] ────── [Pilot Jet]
         │                    │
    [Drain Screw]        [Mixture Screw]
                               │
                          (Hidden behind anti-tamper plug)

If you’ve been wrenching on a scooter, dirt bike, or a small ATV (like the Yamaha Vino 125 or early Suzuki Burgman), you’ve likely met the Mikuni BS25. It’s a reliable, constant-depression (CV) carburetor, but it has a dirty little secret: Its vacuum diaphragm is a ticking time bomb.

Searching for a "Mikuni BS25 carburetor diagram patched" usually means one thing: You’ve found a hole in your rubber slide diaphragm, tried to fix it, and now you’re lost in the vacuum lines. mikuni bs25 carburetor diagram patched

Let’s look at the anatomy of the BS25 and explain why "patched" is often a four-letter word.

If you are looking at a diagram because you need to repair a patched carb, stop patching. Follow this flowchart of salvation: The official factory diagram (available in service manuals)

  • Are the plastic vacuum nipples broken?
  • Are the jets clogged because the patch glue dissolved?

    • The "patched" diagram is a user-modified version of the official schematic, typically found on forums like ScooterInvasion, ADVRider, or ThumperTalk. A user takes the official JPG or PDF, opens it in Paint, Photoshop, or even a PDF editor, and patches the errors.

    Here is exactly what the mikuni bs25 carburetor diagram patched corrects: Why the original diagram fails: [Choke Plunger] ────