Yamaha Zuma/BWS/C3 EFI Fuel Tuner (Beast Mode)

The **Rolling Wrench Beast Mode EFI Fuel Tuner** is the simplest, most rider-friendly way to tune your fuel-injected Yamaha Zuma (50cc or 125cc), Zuma big-bore setups, or even fuel-injected Yamaha C3 builds. No laptop, no software, no stress — just plug the unit into your stock harness and start tuning.

From the factory, the Zuma runs extremely lean. This tuner lets you correct that quickly, whether you’re running fully stock or you’ve added a big bore kit, intake, exhaust, or just want more control over your scooter’s fueling.

Why it’s awesome:
• Installs in under 5 minutes
• 100% plug and play — no splicing needed (ever)
• Adjust AFR in **500 RPM increments** (from 500 to 15,000 RPM)
• Save **two completely separate maps**
• Works on all fuel-injected Zumas (50cc, 125cc, stock + big-bore)
• Can add or reduce fuel at any rpm range
• Perfect for fine-tuning intakes, exhausts, or big-bore kits
• Optional wideband O2 sensor makes tuning even easier
• And yes — it now includes the option to **remove the rev limiter** for better top speed

This tuner unlocks the Zuma’s hidden performance while letting you tune with simple button presses. No more pulling the carb apart over and over like the old days — this is the modern, easier version of tuning.

• This tuner’s main job is to correct the Zuma’s **lean factory fueling**.
• Don’t expect dramatic horsepower gains — fueling correction is about health, consistency, and unlocking the engine’s proper potential.
• If you’ve added an intake, exhaust, or a big bore kit, this tuner becomes **necessary** for safe operation.
• Highly recommended to pair with a **wideband O2 sensor** if you want perfect AFR readings.
• Works on EFI models only — not carbureted scooters.

Used correctly, this tuner makes your Zuma run the way it should’ve from the factory.