NK Racing CT125 428 to 420 Conversion Set (RK Gold Sealed Chain & FR Sprocket)

428 to 420 conversion set
A 428 size chain is over-spec for a 125cc engine capacity.
The Super Cub C125, GROM, and Wave125, which use the same engine as the CT125 but have even higher output, all use 420 size chains.

The effect of downsizing from a 428 to a 420 chain is smoother acceleration and deceleration due to weight reduction. Acceleration will improve, and braking will become more effective. Drag will also decrease, leading to better fuel economy. Of course, top speed will also increase, and using a sealed chain will extend the maintenance cycle; a sealed 420 chain will require less frequent adjustment than a non-sealed 428 chain.

Matching front and rear sprocket set

Gold Seal Chain RK 420 KLO -120 (clip type)
Cutting is required as the chain has 120 links.
(The CT125 has 108 chain links)

Sprocket 420-14 OSAKI
Sprocket 420-39

The 428 size is over spec for 125cc engine capacity.
The Super Cub C125, GROM, Wave125, etc., which have the same engine as the CT125 but even higher output, are 420 size.

The effect of downsizing from a 428 to a 420 chain is smoother acceleration and deceleration due to weight reduction. Acceleration is better and braking is more effective. Fuel consumption is also improved due to reduced drag. Of course, the maximum speed is also increased, and the maintenance cycle is lengthened by using a sealed chain.

Sprockets, front and rear, are set to match.

Seal chain gold RK 420 KLO -120 (clip type)
CUT is necessary because the number of chain links is 120.
(CT125 has 108 chain links)

Sprocket 420-14 SCORPION
Sprocket 420-39