I am fed up by trying different settings but still couldn't get the idle settings for fuel and power both. Will try once again in morning and if it got fixed then fine otherwise will visit yamaha service centre.
I guess that tappet and carb both are related to each other and if any one is out of recommended settings,we just can't fix the other one so we must have to follow those settings. However, for YB 125z tappet adjustment 0.10 and 0.12 performs better than 0.09 and 0.11. For carb we need to open up all the way that screw to make the mixture rich and then start tightening it. Now here at one point bike RPM will increase and that is the most rich mixture settings we need to set but at this point we never been able to achieve better mileage. These butterfly carbs are tricky and it's hard to catch higher RPM until we tighten the screw very very slowly like 1/8 turn.