Athena Big Bore Cylinder Kit 290cc - Kawasaki KX250F (2009-2010)

Race-Ready 290cc Big Bore Kit for KX250F

Athena big bore cylinder kit transforms your KX250F into a 290cc powerhouse. Complete race-spec kit with aluminum cylinder, forged piston, and gaskets—serious power gains for competitive racing.

Why Athena Big Bore Kits

✓ 290cc displacement (from 250cc)
✓ 83mm bore (oversized)
✓ Aluminum cylinder – nickel carbide coating
✓ Forged piston with moly coating
✓ Enlarged water jackets – better cooling
✓ Complete kit – cylinder, piston, gaskets
✓ Race-proven performance
✓ Professional-grade quality

What's Included

✓ Aluminum cylinder (83mm bore)
✓ Forged piston with molybdenum coating
✓ Rings, clips, wrist pin
✓ Complete Athena top end gasket set
✓ All required seals and hardware

⚠️ **Does NOT include cylinder head** (uses your OEM head)

Does It Fit?

✅ **Kawasaki KX250F** (2009-2010)

Quick Specs

Part #: P400250100013 / 0931-0308
Bore Size: 83.00mm
Displacement: 290cc (from 250cc)
Compression Ratio: 13.5:1
Cylinder: Aluminum with nickel-carbide coating
Piston: Forged with moly coating
Engine Type: 4-stroke
Weight: 3.03 lbs

Premium Cylinder Construction

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

**Enlarged Water Jackets:**
Improved cooling system design handles increased heat from larger displacement

**Aluminum Construction:**
Lightweight performance design

Forged Piston Technology

**Molybdenum Coating:**
Reduces friction and wear for longer life

**Forged Construction:**
Stronger than cast pistons—handles higher compression and heat

**13.5:1 Compression:**
High compression ratio for maximum power

Race-Ready Power Gains

**290cc vs. 250cc:**
40cc displacement increase delivers substantial power and torque gains throughout the powerband

**More Displacement = More Power:**
16% increase in displacement means serious horsepower gains

Complete Top End Kit

**Everything Included:**
- Cylinder (83mm bore)
- Forged piston
- Rings, pin, clips
- Complete gasket set
- All seals
- All hardware

**Uses OEM cylinder head** (not included)

Installation Notes

⚙️ Difficulty: Advanced
🔧 Tools: Engine tools, torque wrench, measuring tools
🔧 Time: 4-6 hours
👨🔧 Professional installation highly recommended

Pro Tip

💡 When installing big bore kit, check all clearances carefully. Break in the engine properly—avoid high RPM and heavy loads for first few hours. Use quality oil and proper fuel mapping for the larger displacement.

What Else You'll Need

For installation:
- Engine oil and filter
- Coolant
- Fuel mapping/tuning (highly recommended)
- Valve service (check clearances)
- Timing chain inspection

Fuel Mapping Required

**Important:**
Big bore requires proper fuel mapping/ECU tuning for optimal air/fuel ratio. Stock mapping will run lean—dyno tune recommended.

Enhanced Cooling Design

**Larger Water Jackets:**
Athena redesigned cylinder with increased coolant capacity to handle extra heat from larger displacement

Why Go Big Bore

**More Power:**
Substantial increase in horsepower and torque

**Better Acceleration:**
More displacement = faster acceleration

**Competitive Edge:**
Race-legal power upgrade in many classes

**Bolt-On Power:**
No other engine mods required

Uses OEM Cylinder Head

**Cost Savings:**
Reuses your OEM head—no need to buy expensive head

**Simple Install:**
Just replace cylinder and piston assembly

Athena Quality

Athena is a world leader in 2-stroke and 4-stroke engine components. Their big bore kits are used by professional racers worldwide.

⚠️ California Prop 65 Warning

This product contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.

Questions?

📞 541-668-7503
📧 Support@dunegoonshop.info

Ships same day before 3pm EST ⚡
In stock - Ready to ship!