My bike's rpm increases after a short ride of 5 kms such that it moves forward even if the throttle is in its resting state. I know there is a throttle movement adjusting nut but not sure should I adjust the freeplay of the throttle or should I decrease the rpm using the carburettor idling speed adjusting screw. Its a 125 cc honda shine bike.
Check the carburetor: inside there is a cylinder with a spring attached: shut the fuel off remove the two bolts carefully . one on each side of the carburetor. On the top of the carburetor there is a cap. Unscrew it carefully slide out the cylinder check the spring check the cylinder it's a brass color make sure everything is clean inside and put it all back together and careful with the gasket: if it's dirty use carburetor cleaner to clean it. Let it dry just put a light coat of oil on the cylinder. The spring that returns the cylinder could be weak and allowing the cylinder not close::::