[SpudRider]

The Honda, CRF and XR rear sprokets are nearly identical to many KTM rear sprockets; the only difference is the diameter of the centerline of the bolt holes.

The centerline of the bolt holes for the Honda, CRF and XR rear sprockets has a diameter of 153mm.

http://www.jtsprockets.com/catalogue/sprocket/JTR210



The centerline of the bolt holes for many KTM rear sprockets has a diameter of 150mm.

http://www.jtsprockets.com/catalogue/sprocket/JTR897



I suspect the Zongshen RX3 employs KTM rear sprockets. However, either Honda or KTM rear sprockets will serve well, since they are available with a wide range of teeth. The Honda sprockets basically span 38-53 teeth, and the KTM sprockets basically span 38-52 teeth.

The Minski TRX 300i sold in Russia employs a 13T/37T sprocket combination, since it has a larger, 17-inch rear wheel. The Zongshen RX3 employs a 13T/44T rear sprocket, since it has a 15-inch rear wheel.

If one installs a larger rear wheel on the CSC Cyclone RX3, he will undoubtedly want to switch to a 13T/38T, 14T/40T, 15T/43T, or 16T/46T sprocket combination. Of course, if one switches from the stock sprocket combination, the chain length will also likely change.