Yamaha bike missing beats and how to increase milage?

ITS SIMPLE to do…remove the spark plug from engine..place the plug over the cooling fins, with cable connected to it.shut off the fuel valve.turn the IGN key.the plug must be firm in place with contact with fins.tip of the spark plug must be within your vision.crank the engine with your left hand…fiercely..then you can see a brighter blue spark on the tip of the spark plug.if it contains a red or orange with yellow , your IGNITION COIL, OR CDI, OR ENGINE PULSER COIL may damaged.the spark from the plug must be a brighter,with a TIC TIC nosies…….before going to a final verdict, clean the plug with a piece of HACKSAW blade,with a cable end nicely, check again.if still persists replace one with new…if still persists check cables and connections..after all remove the air filter cover,clean the filter element,and filter box.remove the carburettor, dismantle it and clean with brake fluid.clean all screws and washers, check float height, and reassemble again.adjust all screws to specifications.(AIR SCREW AND SLOW SPEED SCREW)..check CHOKE for any jamming…check wheel brakes for a good operation.check CLUTCH PLATES FOR SLIPPAGE…check DRIVE TRAIN SLACK..WILL BE WITHIN A 7mm PLAY…CHECK ENGINE OIL LEVEL, AND COLOUR..IF DIRTY REPLACE IT..in a TWO STROKE ENGINE CHECK 2T OIL SUPPLY AND LEVEL IN TANK..after all start the engine . bike must be in CENTRE STAND.warm the engine by not increasing the THROTTLE,but patiently allowing the engine to run for a ten minute in slow speed.then TIGHTEN THE AIR MIXING SCREW FULL…now the engine noise will be differ, and it starts to STALL…increases the throttle,till tick over..hold the throttle there…then SLIGHTLY TURN THE AIR SCREW OUTWARDS..HALF A ROUND ALL THE TIME TO THE 360 DEGREE..then YOU WILL REACH A POINT THAT ENGINE RUNS IN A MAXIMUM RPM….for a good adjustment you need a TACHO METER..shows engine speed..then release the throttle, and set it to the minimum tick over speed, or a 1200 to a 1400 RPM is good.if still problem persists YOUR BIKE MAY NEED A FULL OVERHAULING….BY PISTON< AND CRANK, OR MAY DAMAGED OIL SEALS AND PACKINGS...