CILOYU 420 Sprocket 40T 40mm Bore Replacement for Coleman BT200X CT200U CT200U-EX Mini Bikes

Upgrade your mini bike with the CILOYU 420 Sprocket 40T

Refresh a worn or undersized drive gear with a purpose-built 420-chain compatible sprocket that uses a 40 mm bore and a 40-tooth geometry. The CILOYU 420 Sprocket 40T delivers a solid, dependable feel in everyday riding while preserving smooth power transmission across varied surfaces. This part is a practical option for riders who want steadier take-offs and a confident gear engagement on a range of small bikes and go-karts, from Coleman BT200X to Predator-powered setups.

Fitment and compatibility

• Designed for 420-chain systems and 40T gearing to refresh the drive train on compatible builds.
• Widely compatible with Coleman BT200X, CT200U-EX, CT200U, CT100U, and related mini bike models.
• Also suitable for Baja MB165/MB200, Hensim MB165/MB200, MASSIMO MB200, TrailMaster MB200, and Axis M200 platforms.
• Works with Baja Doodlebug DB30, Motovox MBX10/MBX11, Monster Moto MM-B80/MM-B105, and other 420-chain machines.
• Compatible with Predator 212cc engines and similar small-displacement setups that use a 420 chain.

What’s included and installation notes

• 1 x 420 chain 40T sprocket designed for 420-chain systems
• 5 x master links
• 10 x screws
• 10 x nuts

The mounting pattern offers flexibility: the center-to-center distance for the six-hole configuration is about 49 mm (1.93 inches), while the four outer holes use an 80 mm (3.15 inches) bolt circle. This arrangement supports installing the sprocket on many mini bikes, including CT200U and BT200X models, while the six inner holes provide broader compatibility with other engines and frames.

Performance and durability notes

• The larger 40T design provides more drive surface, which can translate to stronger acceleration and better climbing power across mixed terrain.
• Precision-cut teeth help improve engagement with the chain, potentially reducing wear and promoting consistent power delivery.
• The combination of a bigger sprocket and robust bore is built for regular use in off-road or variable-terrain rides, with maintenance in mind.

If you’re upgrading a mini bike for weekend adventures, this replacement sprocket offers a practical path to refreshed performance. Individual results can vary based on model, engine condition, and riding styles, so consider this part as a meaningful possibility rather than a guaranteed outcome.