This is a to understanding, reading, and using the Suzuki GN125 wiring diagram . The GN125 (kick-start and electric-start models, circa 1990s–2000s) has a simple but specific DC-CDI system. 1. Key Features of the GN125 Electrical System | Feature | Description | |--------|-------------| | Battery | 12V, 5Ah–9Ah (maintains DC lights, horn, signals) | | Ignition | DC-CDI (runs off battery, not a magneto) | | Charging | Single-phase permanent magnet alternator + rectifier/regulator | | Fuses | Main 15A (often near battery) + optional sub-fuse | | Starter | Electric start + kick start backup | | Lighting | DC headlight (no AC headlight dimming at idle) | ⚠️ Critical : If the battery is dead, the bike will not run – the CDI needs DC power. 2. Main Components (Wiring Diagram Legend) | Symbol / Label | Component | |---------------|------------| | BAT | Battery (12V) | | IGN | Ignition switch | | CDI | DC-CDI unit (4–6 pins) | | HT COIL | Ignition coil | | PU | Pickup coil (inside left engine cover) | | ALT | Alternator (2–3 yellow/white wires) | | RR | Rectifier/Regulator | | START | Starter relay + starter motor | | S/SW | Sidestand switch (some models) | | CL SW | Clutch switch (some models) | | LIGHTS | Headlight (Hi/Lo), tail/brake light | | SIGNAL | Turn signal flasher relay | | HORN | Horn | | NEU | Neutral switch | 3. Typical Wire Colors (Suzuki Standard) | Color | Function | |-------|----------| | R (Red) | Battery positive (unswitched) | | O (Orange) | Switched +12V (after ignition) | | B/W (Black/White) | Ground (chassis/negative) | | G (Green) | Ground in some harness sections | | Y (Yellow) | Alternator AC output (to regulator) | | W (White) | Alternator AC output | | Bl (Blue) | Headlight high beam | | W/Bl (White/Blue) | Headlight low beam | | Br (Brown) | Tail light / instrument lights | | Lg (Light Green) | Turn signal power | | B (Black) | Switched ground (used by CDI sometimes) | | Bl/Y (Blue/Yellow) | Pickup coil signal | | R/W (Red/White) | Starter relay trigger | 4. Simplified Wiring Diagram (Text Layout) BATTERY (+) --[15A]-- IGN SWITCH --+-- CDI (power in) | +-- START RELAY (coil) +-- LIGHTS/SIGNALS/HORN | +-- REGULATOR (output sense) ALTERNATOR --(Y,W)--> REGULATOR --+-- BATTERY (+) +-- CDI (optional charge) PICKUP COIL -----(Bl/Y)---------> CDI CDI -----------(B/W)----------> IGNITION COIL IGN COIL -----------------------> SPARK PLUG
