The best dirt bike chain and sprocket kit depends on your bike, chain size, sprocket teeth, and mounting dimensions. The options below include kits for Razor electric dirt bikes, 420-chain gas dirt bikes, and mini bikes. Choose the RZEOZU MX650 kit for a Razor-style electric bike, the Ultimate 420 set for a broad range of small gas-powered bikes, or the mini bike kit when its 40 mm bore and mounting pattern match your setup.
| Kit | Best suited for | Key details |
|---|---|---|
| RZEOZU MX650 chain and sprocket kit | Razor electric dirt bikes | 9T, 11T, and 13T motor sprockets |
| 428 chain set | Listed Chinese pit and trail bikes | 14T front, 41T rear |
| RZEOZU 65-tooth upgrade kit | Compatible Razor models seeking a 35-chain setup | 65T rear sprocket; MY1020 motor specified |
| Ultimate 420 set | 50cc–170cc dirt bikes and mini vehicles | 120-link chain, 13T front, 35T rear |
| CILOYU mini bike kit | Selected mini bikes and go-karts | 40T sprocket, 40 mm bore, 420 chain |
RZEOZU MX650 Chain And Sprocket Kit
This kit is listed for the Razor MX650, MX500, SX500 McGrath, and RSF650. It includes 9-tooth, 11-tooth, and 13-tooth motor sprockets, allowing riders to choose among different gearing priorities. The product specifies a MY1020 motor and motor-sprocket mounting dimensions of 10 mm length and 8.5 mm width.
Best for: Owners of a listed Razor electric bike who want sprocket options for adjusting the drive setup. A smaller front sprocket is described as better for hill climbing and acceleration; a larger one is intended for faster speeds and reduced gear wear. Limitation: Confirm the motor type and mounting measurements before ordering; the listing does not make this a universal kit.
428 Chain Set With 14T And 41T Sprockets
This set pairs a 428 chain with a 14-tooth front sprocket and a 41-tooth rear sprocket. The listing identifies it for Chinese 50cc, 70cc, 90cc, 110cc, and 125cc pit bikes, trail bikes, quads, ATVs, and motorcycles. It describes the rear sprocket as steel and presents the combination as a replacement drivetrain set.
Best for: Buyers whose vehicle uses a 428 chain and matches the stated engine range and sprocket dimensions. The fixed 14T/41T pairing makes it straightforward to compare with an existing setup. Limitation: The listing does not provide every mounting measurement, so verify the front shaft fit and rear sprocket pattern against your bike before purchase.
RZEOZU 65-Tooth Razor Upgrade Kit
This option is described as a 65-tooth rear sprocket and 35-chain upgrade for the Razor MX650, MX500, SX500, and RSF650. The listing also specifies compatibility with a MY1020 motor and mentions 9T, 11T, and 13T motor sprocket choices. Its details repeat the smaller-sprocket benefits of acceleration and climbing, and the larger-sprocket benefits of speed and reduced gear wear.
Best for: Razor electric dirt bike owners specifically looking for the listed 65-tooth rear and 35-chain configuration. It is a better fit to consider when those specifications match the existing drive system. Limitation: Confirm exactly which components are included and check the 35-chain and motor requirements; the product information does not establish fit for other models.
Ultimate 420 Chain And Sprocket Set
This set includes a 420 chain with 120 links, a master link, a 13-tooth front sprocket with a 17 mm mounting hole, and a 35-tooth rear sprocket with a 76 mm inside diameter. The listing names dirt bikes, ATVs, go-karts, and mini bikes from 50cc to 170cc, including CRF150, YZ80, SSR, Lifan, and Coolster models. It describes the sprockets as stainless steel.
Best for: Riders seeking a complete 420-chain set with a longer chain that can be adjusted using the included master link. The stated engine range and named examples make it easier to screen for potential fit. Limitation: Listed model names do not guarantee compatibility; check chain length, shaft diameter, rear bore, and mounting pattern.
CILOYU 40T Mini Bike Sprocket Kit
This kit combines a 40-tooth sprocket with a 40 mm bore and a 420 chain. The fitment list includes selected Coleman, Baja, TrailMaster, Massimo, Hensim, and other mini bike or go-kart models. The listing emphasizes that the center mounting-hole distance determines fit and notes different mounting-hole arrangements for some mini bike families.
Best for: Mini bike owners whose existing setup uses a 420 chain and matches the 40 mm bore and mounting pattern. It stands out for buyers who need to compare multiple mounting-hole positions. Limitation: Some listed applications have specific engine or model conditions; do not rely on brand name alone to confirm fit.
Buying Guide: How To Choose A Chain And Sprocket Kit
What chain size does your bike use?
Match the chain designation first. A 420 chain and a 428 chain are different specifications, so a kit with the wrong size will not be a direct replacement. Check the markings on the existing chain or consult the bike’s parts information. Also compare the number of links and whether the kit includes a master link.
Do the sprocket dimensions match?
Compare front sprocket tooth count, shaft or mounting-hole diameter, rear sprocket tooth count, inside diameter, and bolt pattern. For mini bikes, measure the spacing between mounting holes where applicable. A listed model name is useful guidance, but matching physical dimensions is a more reliable fit check.
How does tooth count affect the choice?
Changing sprocket sizes changes gearing. The Razor kit descriptions associate a smaller front sprocket with improved climbing and acceleration, while a larger front sprocket is presented as a speed-oriented choice. Do not assume the same result applies identically to every bike; confirm the intended setup and manufacturer guidance.
Is the kit for an electric bike or a gas-powered bike?
Electric Razor models may require a motor sprocket that matches a particular motor and mounting dimensions. Small gas-powered bikes commonly require matching chain size, shaft fit, and rear mounting measurements. Choose a kit designed for your vehicle type and verify its stated requirements before installation.
Frequently Asked Questions
Can I use a 420 chain on a bike designed for a 428 chain?
No. Select the chain size specified for the bike and sprockets. The 420 and 428 kits listed here are separate setups.
Does a kit listed for a bike model always fit?
Not necessarily. Check the chain size, sprocket teeth, shaft or bore dimensions, and mounting pattern against your specific bike.
What does a 120-link chain mean?
It describes the chain’s supplied link count. The Ultimate 420 set says its chain can be adjusted with the included master link, but confirm the required final length for your bike.
Which kit is intended for Razor MX500 and MX650 bikes?
The two RZEOZU kits list Razor MX500 and MX650 compatibility, along with other Razor models. Both specify a MY1020 motor, so verify the motor and measurements before choosing one.