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Start ShoppingATHENA 70cc Big-Bore Piston Kit for 2-Stroke Scooters & Minicross - High-Performance Replacement
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Description
Upgrade your 2-stroke scooter or minicross engine with the ATHENA S4C04760006A 70cc big-bore piston kit. Designed for maximum performance and durability, this high-quality replacement kit delivers enhanced power while maintaining reliability for racing and daily use.
Key Features
- 70cc Big-Bore Displacement: Significantly increases engine power compared to stock 50cc engines, ideal for performance-oriented riders.
- Cast Aluminum Piston with Domed Crown: Lightweight yet durable construction for optimal combustion efficiency and heat dissipation.
- Graphite/Moly Skirt Coating: Reduces friction and wear, extending piston life in high-RPM applications.
- High-Performance Compression Rings: 1.0–1.2 mm ring height ensures proper sealing and reduces blow-by for cleaner engine operation.
- Complete Kit Includes: Piston, rings, wrist pin, circlips, and necessary spacers for seamless installation.
Why Choose This Product
Whether you're racing or commuting, this Athena piston kit delivers unmatched performance for 2-stroke scooters and minicross engines. The precision-engineered components ensure compatibility with liquid/air-cooled single-cylinder engines, while the durable materials withstand high-stress conditions. Perfect for riders seeking to maximize power without compromising reliability.
SKU:
GM3F42595D
MPN:
S4C04760006A
UPC:
8052204295098
Category:
Piston kits & Components
Brand:
Athena
Stock:
In Stock
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Upgrade your 2-stroke scooter or minicross engine with the ATHENA S4C04760006A 70cc big-bore piston kit. Designed for maximum performance and durability, this high-quality replacement kit delivers enhanced power while maintaining reliability for racing and daily use.
Key Features
- 70cc Big-Bore Displacement: Significantly increases engine power compared to stock 50cc engines, ideal for performance-oriented riders.
- Cast Aluminum Piston with Domed Crown: Lightweight yet durable construction for optimal combustion efficiency and heat dissipation.
- Graphite/Moly Skirt Coating: Reduces friction and wear, extending piston life in high-RPM applications.
- High-Performance Compression Rings: 1.0–1.2 mm ring height ensures proper sealing and reduces blow-by for cleaner engine operation.
- Complete Kit Includes: Piston, rings, wrist pin, circlips, and necessary spacers for seamless installation.
Why Choose This Product
Whether you're racing or commuting, this Athena piston kit delivers unmatched performance for 2-stroke scooters and minicross engines. The precision-engineered components ensure compatibility with liquid/air-cooled single-cylinder engines, while the durable materials withstand high-stress conditions. Perfect for riders seeking to maximize power without compromising reliability.| SKU | GM3F42595D |
|---|---|
| MPN | S4C04760006A |
| UPC/GTIN | 8052204295098 |
| Brand | Athena |
| Category | Piston kits & Components |
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Frequently Asked Questions
No. This is a 70 cc piston intended for engines that already have an Athena 70 cc big-bore cylinder or a compatible 70 cc cylinder. It will not fit a stock 50 cc cylinder. Always match the piston to the specific cylinder part number and engine family.
Only if the cylinder is worn, out-of-round, or damaged, or if you are changing displacement. This kit is typically sold as a replacement piston for an existing Athena 70 cc cylinder of the same family. Inspect the cylinder for scoring and measure it according to your service manual before reusing.
On many small 2-stroke scooters and mini bikes you can replace the top end in-frame, but access varies by model. Consult your service manual. You must have enough room to remove the cylinder, piston pin, and circlips safely.
If you are only replacing a worn 70 cc piston with the same-size Athena 70 cc piston, your existing jetting or mapping will usually remain valid. If you’re changing from stock 50 cc to 70 cc, you must rejet or remap to avoid a lean condition and potential engine damage.
Follow the Athena instructions and your engine manual: use fresh premix or correct oil injection, perform several short heat cycles, avoid sustained high RPM or full throttle during the first tank or two, and monitor plug color and engine temperature.
Installation Guide
Difficulty
Medium
Est. Time
1 hr 30 min
Tools Required
- Metric socket set
- Torque wrench (low-range, suitable for 6–10 mm fasteners)
- Allen/hex keys
- Small flat screwdriver or pick for circlips
- Needle-nose pliers
- Feeler gauges (for ring end gap check)
- Piston ring compressor (optional; most small 2-strokes can be done by hand)
- Shop towels and brake cleaner/solvent
- Non-hardening gasket sealer (if specified by service manual)
- Service manual for the specific engine
Pro Tips
- Lay a clean rag in the crankcase opening while working to prevent dropping circlips or small parts inside.
- Always use new circlips; never reuse old ones.
- Lightly oil the piston, rings, and cylinder bore with 2-stroke oil during assembly.
- Verify piston ring locating pins line up with ring gaps before sliding the cylinder on.
- Use a criss-cross torque pattern on cylinder/head nuts and re-torque after the first full heat cycle if recommended.
- Follow Athena’s and the engine manufacturer’s break-in recommendations (short heat cycles, rich mixture, moderate load).
Common Mistakes to Avoid
- Installing piston backwards (arrow or marking should face exhaust port)
- Incorrectly seating or deforming piston ring(s) and chipping ring edges
- Not properly seating wrist-pin circlips or reusing old circlips
- Failing to thoroughly clean crankcase/cylinder of old debris and gasket material
- Not checking and setting ring end gap to manufacturer spec
- Over-torquing or under-torquing cylinder/head nuts
- Skipping proper break-in procedure and running engine at sustained high RPM immediately
Comparison vs Stock/OEM
Compared to a stock 50 cc OEM piston, an Athena 70 cc piston is larger in bore and designed to work with a matching big-bore performance cylinder, typically yielding substantial increases in power and torque. Compared to an OEM 70 cc piston (if the vehicle has one), Athena’s design is oriented toward performance use.
Improvements
- Higher displacement (when paired with 70 cc cylinder) for more torque and acceleration over stock 50 cc engines
- Performance-oriented crown and port-matching design to suit Athena cylinders
- Modern skirt coatings (on many Athena pistons) to reduce friction and improve break-in
- High-quality materials and machining targeted at racing and performance applications
Considerations
- Increased stress on bottom end components versus stock 50 cc setup
- May reduce engine longevity compared to conservative OEM tuning if frequently run at high RPM
- Typically requires appropriate jetting, exhaust, and clutch/variator tuning to fully benefit from the 70 cc displacement
Durability & Warranty
Expected Lifespan
Highly dependent on usage; in race/competition use, piston inspection and replacement intervals can be as short as 20–40 hours. In moderate street use with correct tuning, significantly longer intervals are common, but top-end inspection is still recommended at regular service hours.
Warranty
Athena generally offers a limited manufacturer’s warranty against defects in materials and workmanship, but not against wear, improper installation, or racing damage. Exact terms and coverage for S4C04760006A must be confirmed with Athena or the selling retailer.
Maintenance
['Regularly check compression and engine performance to catch early signs of wear.', 'Inspect piston crown and exhaust port for signs of detonation or lean running.', 'Use high-quality 2-stroke oil and proper premix or injection settings.', 'Adhere to recommended service hours for top-end inspection and ring replacement, especially in racing conditions.']
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