CILOYU 35 Roller Chain and 40T Rear Sprocket Kit — 37mm Bore, 6-Hole Mount for Mini Bikes, Heavy-Duty Alloy

CILOYU's 35 chain paired with a 40-tooth, 37 mm bore rear sprocket is a direct-fit, heavy-duty replacement designed to restore reliable power transfer on compatible mini bikes.

When a worn chain or stripped sprocket is slowing your mini bike, swapping both to a matched CILOYU kit is a straightforward way to regain smooth drivetrain performance. This assembly is engineered for a wide range of small-displacement engines and popular mini bike models, with upgraded mounting holes and a thicker metal alloy for longer life under load.

Which mini bikes and engines will this chain and sprocket fit?

This combo was made to work with many common small-engine mini bikes and aftermarket conversions. It suits Predator 97–100cc clones, Coleman and Baja mini bikes, Motovox models, and select Monster Moto variants when the hub bore and mounting pattern match.

• Compatible engines: Predator 97cc, 98cc, 100cc; 2.5–3.0 hp small engines
• Models: Coleman CT100U, CC100X, RB100; Baja Doodle/DB30 family; Motovox MBX10/MBX11; Monster Moto Mega Moto
• Chain size: ANSI 35 roller chain standard
• Sprocket specs: 40 teeth, centre bore 37 mm, mounting hole distance 49 mm

How does the improved 6-hole sprocket make installation easier?

The sprocket adds a 6-hole mounting pattern with refined spacing so it lines up with a wider variety of hub plates. That reduces the need for time-consuming shims or adapters and helps you mount the part without modification.

• Six evenly spaced mounting holes for better alignment
• Mounting hole center distance: 1.92" (49 mm) for common hubs
• Designed to avoid interference with brake plates and axle hardware
• Machined hole edges for easier bolt insertion during fit-up

What durability and performance benefits does this kit deliver?

The sprocket and chain are constructed from a thicker metal alloy to resist wear, bending, and accelerated tooth loss. The 40-tooth rear sprocket paired with a 35 chain yields a transmission ratio that favors higher top speed and efficient power transfer for varied terrain.

• Thicker alloy construction for longer service life under load
• 40T sprocket enables faster drive ratio compared with smaller rear sprockets
• Roller chain design reduces friction and improves longevity
• Can improve fuel economy slightly by optimizing gear ratio

What exact dimensions and specifications should I check before buying?

Measure your existing hub and chain before ordering to confirm compatibility. Key dimensions are the centre bore, the mounting hole spacing, and the chain pitch; mismatches are the most common cause of fit issues.

• Centre bore diameter: 37 mm (1.45") — must match hub bore
• Mounting hole distance: 49 mm (1.92") — check bolt circle alignment
• Tooth count: 40T rear sprocket
• Chain size: ANSI 35 roller chain pitch and width

Who is this for: Riders, mechanics, and DIY tinkerers who maintain small-displacement mini bikes and need a reliable drivetrain replacement. This CILOYU 35 chain and 40T sprocket suit owners of Coleman, Baja, Motovox, Motormax/Monster Moto and Predator-powered mini bikes looking for a durable, easy-to-fit rear sprocket and matching chain to restore performance or change gearing. Confirm bore and bolt-circle dimensions before purchase to ensure a correct, hassle-free installation.