IT USUALLY TAKES 2 SECONDS TO START THE MOTOR. NOW, IT TAKES OVER 40 SECONDS AT 7 AM. IT ALMOST KILL THE BATTERY. IF YOU PARK FOR 1 HOUR, 2ND START TAKES 10 SECONDS. IS THIS HAPPENING BECAUSE THE VALVES NEEDS ADJUSTING? HOW AND WHAT IS THE EASY WAY OF VALVES TUNE-UP?
Good call, it most likely is the valve clearance. As the valves wear, they get tighter until they actually stay open a bit (when cold). As the engine warms up, the aluminum head pushes the cam away from the valve stems a bit, and some clearance comes back. Check 'em, adjust 'em, and you should be good to go. For most chinese 150's, you'll need to remove the plastic around the engine, then pull off the valve cover - you'll see the rocker arms inside, with locking nuts and adjustment screws. Set the crank at TDC on the compression stroke (about 1/2 turn after the intake valve closes) and then adjust the clearance - get specs from your manual, or just make sure that there's at least 0.1 mm gap if you don't have the specs.
MY MECHANIC TOLD ME: AT 9000 MILES, SCOOTER IS DUE FOR VALVE ADJUSTMENT. EVERYTHING ELSE SHOULD BE OK. 1] WAIT UNTIL MOTOR COOLS OFF 2] REMOVE PLASTIC VALVE COVER 3] LOOSEN RIGHT FENDER TO GET EASY ACCESS TO VALVES 4] USE 8 MM SOCKET TO TAKE OFF THE FOUR VALVE COVER SCREWS 5] USE 10 MM SOCKET TO TAKE OFF THE LAST TWO NUTS 6] REMOVE ALUMINUM VALVE COVER 7] PISTON MUST BE FIRST COME ALL THE WAY UP BEFORE ADJUSTING VALVES 8] CHAIN AND DISK HAS 3 HOLES, SET HOLE ONE UP, HOLE TWO DOWN, AND HOLE THREE TO THE LEFT [ IN THE MIDDLE BETWEEN THE TWO VALVES. 9] MUST HAVE A GAGE FEELER SIZE 3/1000, AND 4/1000 $7 SET AT ADVANCE AUTO 10] USE 9 MM SOCKET TO LOOSEN THE TOP INTAKE VALVE NUT USE GAGE SIZE 3/1000 ON TOP OF VALVE. ADJUST VALVE SCREW, NOT TOO TIGHT, AND NOT TOO LOOSE HOLD THE TOP SCREW WITH A PLIER WHILE TIGHTENING THE TOP NUT WITH 9 MM OPEN WRENCH. MAKE SURE THE NUT IS GOOD AND TIGHT. MINE WAS MOVED TO SIZE 7/1000 MM, THEREFORE, IT WAS HARD TO START. 11] USE 9 MM SOCKET TO LOOSEN THE BOTTOM EXHAUST VALVE NUT USE GAGE SIZE 4/1000 ON TOP OF VALVE. ADJUST VALVE SCREW, NOT TOO TIGHT, AND NOT TOO LOOSE HOLD THE TOP SCREW WITH A PLIER WHILE TIGHTENING THE TOP NUT WITH 9 MM OPEN WRENCH. MAKE SURE THE NUT IS GOOD AND TIGHT. MINE WAS MOVED TO SIZE 2/1000, IT WAS HARD TO START. 12] HOOK THE GROUND WIRE, AN CHECK IF IT IS EASY TO START 13] ONCE IT HAS GOOD START, PUT THINGS BACK IN REVERSE AS THEY WERE. 14] FIRST PUT COVER AND ALL SCREWS HAND TIGHT ONLY, THEN TIGHT THEM GOOD. I STARED TIGHTENING THEM ONE AT A TIME, THEN THE LAST ONE WOULD NOT FIT I HAD TO LOOSEN ALL OF THEM AND GET THEM ALL STARTED AND HAND TIGHT FIRST. 15] ADVANCE AUTO MAY LET YOU USE SOME LOANER TOOLS 16] PUT EVERYTHING BACK TOGETHER AND YOU READY TO GO FOR 5000 MILES. GOOD LUCK, WERE YOUR HELMET, AND DRIVE CAREFUL. TRY NOT TO DRIVE IN BAD WEATHER WEATHER LINK: www.spc.noaa /
Dear god I wouldn't touch the valves lol. Start with spark plugs. It should have 1-3 plugs. After plugs, check distributor. After that check carburetor. Plugs/dist are common problems with running/starting issues.