CILOYU 420 40-Tooth Sprocket 40mm Bore for Mini Bikes — 4/6-Hole Mount, Includes Hardware

High-strength CILOYU 420 40-tooth sprocket with a 40mm center bore and multiple mounting hole patterns for reliable mini bike power delivery.

This aftermarket 420 chain sprocket is engineered to fit a wide range of small-engine mini bikes and go-karts, offering larger gearing, improved torque transfer and broader compatibility than many stock sprockets. It’s supplied as a complete kit with mounting fasteners and master links so you can replace the drive component and reinstall the chain quickly.

Which mini bikes and engines will this sprocket fit?

The CILOYU 420 40T sprocket was designed for popular small engines and mini bike platforms, spanning Predator, Coleman, Baja and several OEM clones. Compatibility covers many 200–212cc kits plus a variety of 6.5hp and similar powerplants where a 420 chain is used.

• Predator 212cc, 196cc, 200cc engines and 6.5hp class models
• Coleman Powersports CT200U, BT200X, CT100U, CC100X platforms
• Baja, Hensim, Massimo, TrailMaster and Axis mini bike/MB200 family
• Monster Moto and Motovox compatible models that use 420 chains

How does the multi-hole pattern improve fit and installation?

This sprocket includes both a 4-hole and a 6-hole bolt circle so it can mount to different crank or hub patterns without needing adapters. The additional mounting options make the sprocket usable on machines with larger engines or modified setups, reducing the chance you’ll need custom machining.

• 6-hole bolt circle: 1.93" (49 mm) center-to-center for select models
• 4-hole bolt circle: 3.15" (80 mm) center-to-center for other mini bikes
• 40mm center bore to accept common shafts without extra hubs
• Pre-drilled holes let you reuse existing fasteners or the supplied hardware

What performance differences can I expect compared to stock sprockets?

Moving to a larger 40-tooth 420 sprocket increases torque at the rear wheel, improving acceleration and hill-climb capability at similar engine RPMs. The tooth profile and material are chosen to deliver smoother engagement, which reduces chain wear and can extend service intervals.

• Larger tooth count gives stronger low-end acceleration and climbing power
• Precision-cut teeth promote consistent chain contact and less slippage
• Durable construction helps resist deformation under load
• Comes with master links to restore chain integrity during installation

What hardware and sizing details are provided in the kit?

The package contains the sprocket plus the fasteners you need to mount it and reconnect the chain. Exact dimensions are listed so you can verify clearance and chain alignment before installation.

• Teeth: 40T sized for 420 chain systems
• Center bore: 1.57" (40 mm) to fit common shafts
• Hardware included: 10 screws, 10 nuts, and 5 x 420 master links
• Packed as a ready-to-install kit to minimize downtime

Who is this for: Riders and mechanics replacing worn drive sprockets, upgrading for better torque and climbing, or swapping gearing for a different final drive ratio. It’s suited to hobbyists, repair shops and anyone running Predator, Coleman, Baja, Hensim, Massimo or similar mini bike/go-kart engines that require a 420 chain and want a robust, multi-pattern mounting solution.