KTM 125 BIG BORE KIT 65MM BY NMW RACING

Engine Specifications

• Bore Diameter: 65.00 mm (Stock is 58 mm)

• Stroke: 47.2 mm (Stock stroke)

• Displacement: Approximately 156.6 cc (commonly marketed as a 160cc kit)

• Compression Ratio: Typically increased to around 13.4:1 (up from stock 12.5:1)

• Cylinder Type: High-quality aluminum for heat dissipation and durability.

Performance Gains

• Power Increase: Can boost wheel horsepower from stock (~14 hp) up to 18–20 hp, depending on tuning.

• Torque: Significant improvement in mid-range torque, making the bike feel much “punchier” in city riding and roll-on acceleration.

Important Notes for Installation

1. ECU Tuning: Because you are moving from 125cc to 160cc, the stock fueling will be too lean. It is highly recommended to use a fuel X or a Piggyback ECU to adjust the air-fuel ratio.

2. Compatibility: This kit is designed for the 4-stroke DOHC engine (Duke/RC 125). It will not fit the 2-stroke SX/EXC models.

3. Valve Clearance: NMW often recommends pairing this with their Stage 1 or Stage 2 Big Valves to maximize the airflow for the larger displacement.