The "Periodic Maintenance / Lubrication Intervals" schedule is taken directly from a 1968 edition Honda PC50/PS50 Factory Service Manual, which covers the '68 models (other models should be similar).  Before starting any work, always consult the manual for your scooter's model & year and be sure you know what you're doing.
 

Periodic Maintenance Intervals

Item

Remarks

Type

 300 mi (500 km) 1000 mi (1600 km) 2000 mi (3200 km) 3000 mi (4800 km) 4000 mi (6400 km) 5000 mi (8000 km) 6000 mi (9600 km)
Front / rear brake lever play Check for proper function   Inspect before every ride
Fasteners Check for proper tightness   Inspect before every ride
Lights and horn Check for proper operation   Inspect before every ride
Front / rear tire pressure Front 18 psi, Rear 24 psi Front 2.00 x 19
Rear 2.25 x 19		 Inspect before every ride
Change engine oil Quantities: PC50 - 0.8 liter, PS50 - 0.9 liter SAE 10W-30 motor oil X X X X X X X
Adjust throttle cable Adjust the adjusting screw to remove excessive free play     X X X X X X
Adjust decompression cable (PC50) 0.4-0.6" (10-15mm) free play             X  
Adjust gear change cable (PS50) 0.4-0.6" (10-15mm) free play             X  
Adjust brakes 0.4-0.6" (10-15mm) free play     X X X X   X
Clean air cleaner To clean, remove element and tap it, or wash in water Air dry - do not oil.       X     X
Greasing Apply grease to all grease nipples         X     X
Adjust drive train Check for loose components and tighten     X X X X X X
Adjust valve clearance Clearance is .002" (.05mm)         X     X
Adjust ignition timing Point gap is .012-.016" (.3mm-4mm)         X     X
Adjust carburetor Clean and adjust as needed. Float level is 4mm +/- 1mm.     X   X     X
Clean spark plug .024" - .028" (.6-.7mm)
 C-6HB, for higher speeds use a C7HS       X     X

Battery type: 6N22A