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Rolling Wrench

GY6 Stage 1 Engine Package - 172cc

GY6 Stage 1 Engine Package - 172cc

Regular price $468.00 USD
Regular price Sale price $468.00 USD
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Shipping calculated at checkout.

If your GY6 feels slow or falls flat when you need power, stepping up to the 172cc setup is the proven fix. This is the largest displacement you can run without case boring, and it’s known to stay cool and take real-world abuse. You can choose between a Full ProBld (Forged) setup or a Full NCY (Cast) setup depending on your build style — both are reliable, just tuned for different riding priorities.

The Details

The 172cc configuration is the sweet spot for strong, usable power. It’s smoother, faster, and more durable than stock because you're replacing low-grade components with high-quality Taiwanese parts — and without needing to modify your engine case.

Full ProBld (Forged Piston) — Performance + Longevity

  • 4032 forged piston for high strength + daily reliability
  • Rings professionally pre-measured & installed inside the cylinder
  • ProBld Big-Valve Head (28mm / 23mm) with all hardware included
  • 5-axis CNC clocking flange for perfect carburetor alignment
  • NGK spark plug included
  • ProBld performance camshaft tuned for punchy low-mid pull and strong top end

Full NCY (Cast Piston) — Budget-Friendly + Reliable

  • Cast piston — great for everyday riding
  • Rings are not pre-installed (you will gap and install them)
  • NCY Big-Valve Head — we include hardware NCY skips
  • 5-axis CNC clocking flange included
  • NGK spark plug included
  • NCY camshaft for smooth torque at lower RPM

Quick takeaway: Choose ProBld if you want strength, longevity, and less setup work. Choose NCY if you’re working within a budget but still want a solid, daily-friendly upgrade.

Important Things to Note

Verify your engine code before purchasing. This kit fits QMJ157 engines only.

(CLICK HERE) to learn how to check your engine.

Buggy / Go-Kart Owners:
Fitment varies model-to-model. Many owners use the GY6 61mm Test Gasket Kit first to confirm spacing.
(CLICK HERE)

View full details

Customer Reviews

Based on 14 reviews
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Eric VanDyke

Installed the new cylinder and piston. Turned it over by hand and the original valves were leaking. No surprise really with a higher compression. Cleaned and ground the valves and we are getting close to 180 psi and it’s running great! Idles perfectly at very low RPM. Love it.

K
Kenneth Wood

Good quality parts good service, the ruck definitely has more power and torque. Now it’s time to gear up.

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Anonymous

I noticed the power difference instantly

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Anonymous

The Big Bore Kit that I ordered works flawlessly. Installation went smoothly and customer service is Top Notch. She even advised me that it may not fit in my GY6A Buggy, but I ordered anyways and it was perfect. Matt's videos are always helpful and on point with all aspects of the install. Will definitely purchase more from them for my new to me GY6B buggy. Possibly do a 232 Big Bore in the near future.

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Abram

Quality product.