62.5mm Big Bore Complete Cylinder & Head Rebuild Kit for GY6 170cc-200cc Engines: The Ultimate Buyer’s Guide
Introduction
Upgrading your Chinese ATV, scooter, or go-kart with a 62.5mm Big Bore Kit can unlock hidden performance in your GY6 170cc, 180cc, or 200cc engine. But with so many options available, how do you choose the right kit? As a leading manufacturer with 20+ years of engine parts expertise, we’ll break down everything you need to know before buying.
1. What Does a 62.5mm Big Bore Kit Do?
A big bore kit increases your engine’s displacement by widening the cylinder diameter. This delivers:
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10-15% more horsepower (depending on tuning)
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Improved low-end torque for better acceleration
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Enhanced throttle response across all RPM ranges
*”Our CNC-machined 62.5mm kits add 2-3 HP on dyno-tested GY6 200cc engines.”*
2. Kit Components: What’s Included?
A quality rebuild kit should contain:
| Component | Material | Importance |
|---|---|---|
| Cylinder | High-silicon aluminum alloy | Better heat dissipation |
| Piston | Forged aluminum (ours is 4032 alloy) | Handles higher compression |
| Piston rings | Chrome-plated steel | Reduces blow-by |
| Head gasket | Multi-layer steel (MLS) | Prevents leaks |
| Cylinder head | Pre-assembled with valves | Bolt-on ready |
⚠️ Avoid kits with cast iron cylinders – they overheat faster!
3. Compatibility Checklist
Will this fit your engine?
✔️ Fits GY6 variants: 1P63QML, 157QMJ, 1P52QMI
✔️ Works on:
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Tao Tao and Chinese ATVs
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Go-karts (Yerf Dog, Hammerhead)
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Scooters (Qingqi, Roketa)
Measure first:
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Stock bore: 57.4mm (170cc) or 59mm (200cc)
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Requires 62.5mm cylinder jug clearance
4. Material Quality Matters
We use:
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Aircraft-grade aluminum cylinders (vs. cheaper cast iron)
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Forged pistons (20% stronger than cast)
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Japanese-style piston rings for tighter seal
Why it matters:
Cheap kits wear out in <1,000 miles. Ours last 5,000+ miles with proper break-in.
5. Installation Tips
Tools needed:
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Torque wrench (18-22 ft-lbs for head bolts)
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Piston ring compressor
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Gasket sealant
Pro tips:
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Always hone the cylinder before installation
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Soak piston rings in oil for 30 mins
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Torque bolts in crisscross pattern
6. Why Choose Our Kit?
✅ Factory direct pricing (Save 30% vs. retail)
✅ CE/DOT certified materials
✅ 24/7 expert support for installation help
✅ Global shipping from our distribution hubs
Final Verdict
For GY6 engine owners wanting reliable power gains, our 62.5mm big bore kit offers professional-grade components at DIY prices. Properly installed, it transforms sluggish 170cc engines into torque monsters.
Ready to upgrade?
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