try this first of all find the correct idling speed of your vehicle from the owners manual .take the bike for a quick spin (this is mandatory)10 minutes of stop and go riding is enough.Then accurately adjust the idle speed in accordance with the manual by tuning the idle screw .Assuming you have a clean and new air filter and if it has been run for more than 500 km clean it (if you dont know how to there is a video in youtube)any air filter that has been run for more than a 1000 km will not with this method so change it.Install a new spark plug (one is enough).Now after you have heated the engine,adjusted the idle screw now turn the AF screw (also called pilot screw )clockwise counting the no of turns and tighten until it stops to move .dont over tighten it as it may damage the carburetor(the counting is done to revert back to ur current setting if u dont like the tuning).now since you ve fully tigthen it your engine will most probably be stalled dont worry open a little bit of throttle and start her again now again adjust the idle speed to the recommend rpm.now this is the leanest possible mixture.Now slowly turn the af screw counter clock wise and slowly you will notice the rpm increase keep opening the screw till you achieve the highest rpm(in most cases will be 3000 rpm for a mikuni however it varies with the condition of the engine) the correct tuning is just at the point where thr rpm is the increased to the highest point .Now again reduce the rpm to the recommended level.now your byk should be in pretty much stock tuning .to check turn the engine off and run it again .there should be no problemn starting her .the acceleration should be crispy and responsive .ride again for about 5 mins but do not accelerate for more than 1/4 of the total accelerator play.as this tuning the af screw is only for the idle circuit .if this doesnt solve your problem i will be starting a new thread regarding carburetor ,Good point for you is that this method was taught to me by a auto engineering student who also works part time as a supervisior on a bajaj service station.Ive tuned carburetors of all pulsar 150 models ,avenger 180,200,hh karizma,tvs fiero,daelim roadwin ,kinetic honda(which actually made me do research on tuning carb at the first place).hope this helps you and happy riding

Thank you very much.

I have few doubts. pls clarify.

1) Once i tighten up the AF screw my bike stalls once fully closed my bike stops. Fully closed in the sense I dont mean over tightening just normal tight.

So from here I need to start my bike and turn the AF screw anticlockwise? am I right?

When turning anticlockwise I need to check the RPM to reach highest level?

in the meter RPM is 1 2 3 4 5 6 7 8 9 10 11 12 * 1000 What do you mean be highest RPM. Is the meter must reach 12000 RPM. So that I need to stop at this point?

Now my setting is 2.75 full turns out (anti clockwise) And my bike gives between 50 - 55 kmpl in city traffic. 55 kmpl I never achieved but 50 kmpl is guaranteed if the petrol station gives me a good petrol.

As you have experience in tuning. I just want to know few things about the bike.

1) Is there Oil filter in pulsar 150. If so what it does. Is there any time limit
to change it or clean it.
2) How to check my bike is tuned perfectly? any symptoms. Becz I want good mileage at the same time I want my engine to be perfect

Im sorry I couldn't give clear instructions earlier when you turn your af screw anticlockwise then the rpm starts to increase if u observe carefully the rpm goes on increasing as you loosen the AF screw but it will stop increasing once the tuning is achieved .(Note as you start to loosen the AF screw the rpm will start to increase and and remain constant for sometime again it will increase after few more opening of the AF screw this may go on for several times then at a point the rpm will remain constant no matter how much you unscrew this is when the tuning is achieved .for your convinence i will upload a video in youtube today evening or tomorrow .Also before you decide to tune perform a plug chop in your bike .what you do is install a new spark plug (even the cheapest one will do and u can use it as a spare plug in your tool kit after the tune up or you can use your old spark plug but you have to clean it nicely).ride around for about 10 minutes .Do not accelerate more than 1/4 of the total throttle opening as soon as you finish the ride and come home (most probably)give her few burst of full throttle one (in neutral) or two times then accelerate fully and hit the engine kill switch .open the plug and inspect it .if it has a Dark brown shade like a coffee then it is good you don't need to tune the carb if it is white then the mixture is said to be lean (more air less fuel)if it is covered with black shoot then the mixture is said to be rich(more fuel less air).Also some times the a little bit of shoot may indicate clogged air filter element .you dont need to look at whole spark plug just look at the white insulator tip that covers the sparkplugs tip

Hey After Changing my new spark plugs and Air Filter. I got 60 KMPL mileage. Im very happy abt it.