Athena Big Bore Cylinder Kit 144cc - Kawasaki KX125 (2003-2007)

Race-Ready 144cc Big Bore Kit for KX125

Athena big bore cylinder kit transforms your KX125 into a 144cc powerhouse. Complete race-spec kit with aluminum cylinder, high-performance power valves, piston kit, and gaskets—everything for serious power gains.

Why Athena Big Bore Kits

✓ 144cc displacement (from 125cc)
✓ 58mm bore (oversized)
✓ Aluminum cylinder – nickel carbide coating
✓ High-performance power valves included
✓ Complete kit – cylinder, piston, gaskets
✓ Race-proven performance
✓ Professional-grade quality

What's Included

✓ Aluminum cylinder (58mm bore)
✓ Aluminum cylinder head (removable bronze dome)
✓ High-performance anodized power valves
✓ Cast lite flat-top piston
✓ Rings, clips, wrist pin
✓ Complete Athena top end gasket set
✓ All required seals and hardware

Does It Fit?

✅ **Kawasaki KX125** (2003-2007)

Quick Specs

Part #: P400250100011 / 0931-0109
Bore Size: 58.00mm
Displacement: 144cc (from 125cc)
Cylinder: Aluminum with nickel-carbide coating
Head: Aluminum with removable bronze dome
Piston: Cast lite flat-top
Engine Type: 2-stroke
Weight: 5.62 lbs

Premium Cylinder Construction

**Nickel-Carbide Coating:**
Advanced cylinder coating for superior wear resistance and heat dissipation

**Aluminum Cylinder:**
Lightweight performance construction

**Bronze Dome Head:**
Removable dome allows compression tuning

High-Performance Power Valves

**Specially Designed:**
Hard anodized power valves engineered for big bore performance

⚠️ **Important:** Cannot use OEM power valves—must use included Athena valves

Race-Ready Power Gains

**144cc vs. 125cc:**
19cc displacement increase delivers substantial power and torque gains throughout the powerband

**More Displacement = More Power:**
Bigger bore means more fuel/air mixture per cycle

Complete Top End Kit

**Everything Included:**
- Cylinder and head
- Power valves
- Piston kit (piston, rings, pin, clips)
- Complete gasket set
- All seals
- All hard