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Most 150cc scooters on the road — and virtually all Chinese-made models — use the GY6 engine platform, which takes a small handful of well-known spark plugs. NGK is the dominant brand in this space, and the right pick mostly comes down to iridium vs. standard and whether you’ve modified the engine.
| # | Product | Price | Where to buy |
|---|---|---|---|
| 1 | NGK Iridium CR7HIX | $8–$14 | Amazon · eBay |
| 2 | NGK C7HSA Standard Spark Plug | $3–$6 | Amazon · eBay |
| 3 | NGK Iridium CR8HIX (Colder Heat Range) | $8–$14 | Amazon · eBay |
The picks, in detail
NGK Iridium CR7HIX
The top recommendation for GY6 50cc–150cc engines — an iridium-tipped plug that improves spark quality and lasts far longer than a standard plug.
- Iridium electrode tip
- Pre-gapped from the factory
- Fits GY6 50–150cc engines
- Improved cold-start and idle quality
- Longer service life than standard plugs
- Better spark consistency, especially if rejetted
- Direct fit — no adapter needed
- Costs more than a standard plug
- Manufacturer advises against re-gapping — the fine electrode can break
NGK C7HSA Standard Spark Plug
The budget-friendly, traditional-electrode option — a reliable direct-fit plug for stock 150cc GY6 scooters that don’t need the iridium upgrade.
- 10mm thread, 12.7mm reach
- Traditional copper-core electrode
- Direct GY6 fit
- Inexpensive and easy to find
- Proven reliability on stock engines
- Simple to gap and swap
- Shorter service life than iridium
- Slightly less consistent spark under load
NGK Iridium CR8HIX (Colder Heat Range)
A colder heat-range iridium plug for modified or higher-compression GY6 builds — helps prevent pre-ignition when the stock CR7HIX runs too hot.
- Colder heat range than CR7HIX
- Iridium electrode tip
- Same thread/reach as standard GY6 plugs
- Reduces knock/pre-ignition risk on tuned engines
- Iridium durability
- Drop-in fit for GY6-based bikes
- Overkill — and can foul — on a stock, unmodified engine
- Pricier than the standard heat-range plug
Buying tips
- Stick with the CR7HIX heat range unless you’ve modified the engine (big-bore kit, higher compression, forced induction) — running too cold a plug on a stock engine can cause fouling.
- Iridium plugs are pre-gapped at the factory — don’t try to adjust the gap, the fine electrode can snap.
- If you’re rejetting the carburetor, an iridium plug is worth the upgrade for more consistent spark under the new fuel curve.
As an Amazon Associate and eBay Partner, toptenpick.com earns from qualifying purchases. Prices and availability are subject to change.