MFC·passion Racing Scooter Variator Kit for GY6 50-100cc — Red Front Clutch with 5g/7g/9g Rollers, Durable Metal

MFC·passion Racing Scooter Variator Kit is a complete front clutch variator assembly with interchangeable 5g, 7g and 9g rollers designed to upgrade performance and tune acceleration for GY6 50cc–100cc 4-stroke engines.

This red variator assembly is built to fit the common GY6 family—models 139QMB and 139QMA—used in many Chinese scooters, mopeds, ATVs, quads and go-karts. Made from durable metal and supplied with three sets of rollers (3×5g, 3×7g, 3×9g), it gives you flexible gearing and a direct replacement for worn or stock parts. The kit’s dimensions and boss bush match industry standards to simplify installation on compatible engines from brands like Lifan, Loncin, Zongshen and Taotao.

How does this variator kit affect acceleration and top speed?

Changing roller weights shifts the CVT engagement profile: lighter rollers let the engine rev higher for quicker acceleration, while heavier rollers favor lower RPMs and a higher theoretical top speed. This kit includes 5g, 7g and 9g rollers so you can test multiple setups and find the balance that suits your riding style.

• 5g rollers: quicker clutch engagement, sharper initial acceleration
• 7g rollers: balanced response for mixed use
• 9g rollers: smoother pull, potential for higher cruising speed

Will this variator assembly fit my scooter or ATV?

The assembly is sized to fit GY6 50cc, 80cc and 100cc 4-stroke engines identified as 139QMB/139QMA. Check the variator O.D., I.D. and boss bush dimensions against your current part to confirm compatibility. It’s a common fit for many Chinese-made engine platforms.

• Variator outer diameter: 90mm (3.54")
• Inner diameter and boss bush: 20mm I.D.; boss 20×38mm
• Roller dimensions: 16×13mm with 5g, 7g, 9g weights included

What materials and build quality should I expect?

This variator assembly is manufactured from high-quality metal for improved wear resistance compared with lower-grade castings. The rollers are precision cut to consistent weight values so tuning results are repeatable. That makes the kit suitable for routine commuting or performance-focused tweaks.

• Durable metal variator housing for longevity
• Consistent, factory-weighted rollers for accurate tuning
• Red finish for corrosion resistance and easy visual inspection

How easy is the kit to install and what’s included?

Installation follows standard variator replacement steps and requires basic tools: puller for the variator if needed, socket set and torque wrench. The package contains a full variator assembly and three sets of three rollers (3×5g, 3×7g, 3×9g), ready to drop into models that match the dimensions listed.

• Included: 1 complete variator assembly
• Roller sets: three each of 5g, 7g and 9g (total 9 rollers)
• Compatible with many GY6-based scooters and small ATVs

Who is this for: This MFC·passion Racing Scooter Variator Kit is ideal for riders who maintain or upgrade Chinese GY6-based scooters, small ATVs and go-karts—mechanically inclined DIYers, scooter tuners and small repair shops. Choose this kit if you want a direct-fit replacement with the flexibility to test roller weights for improved throttle response and ride feel without complex modifications.