I'm using Yamaha SZR 2011 model. It has completed 65K now. Still running smoothly except the below problem. Hope the experts here can help me.

Idle RPM is very low. I have adjusted the screw to full tight but the RPM is not increasing more than 1000. This is making starting trouble and the engine will turn off when releasing acceleration while running. And the bike will never start if I pull the choke cable. I have cleaned the carburettor and air filter is new. Please someone help me on this. Local mechanic is not interested to handle this as the bike running without any problem.