The "Periodic Maintenance / Lubrication Intervals" schedule is taken directly from a 1988 edition Yamaha CW50 factory owner's manual. Before starting any work, always consult the manual for your scooter's model & year and be sure you know what you're doing.

CW50 Periodic Maintenance / Lubrication Intervals

Item	Remarks	Type	Break-in 300 mi (500 km)	Thereafter every 2,000 mi (3,000 km) or 6 months	Thereafter every 4,000 mi (6,000 km) or 12 months
Spark plug	Inspect/Clean or replace as required	NGK BPR7HS .024" -.028" gap	X	X	X
Air filter	Wash & damp with oil	-	X	-	X
Carburetor*	Check operation. Adjust if necessary	-	-	X	X
Fuel line*	Check fuel hose for cracks or damage. Replace if necessary	-	X	-	X
Brake system	Adjust free play. Replace shoes if needed	Front DP9140, Rear DP9140	-	X	X
Autolube pump*	Check. Adjust and bleed air as needed.	-	X	-	X
Wheels & tires*	Front 15 psi, Rear 18 (21 max) psi	Front 4.00 or 120/90 x 10, Rear 130/90 x 10	-	X	X
Suspension system*	Check operation. Repair as required	-	X	X	X
Battery*	Top with distilled water. Check specific gravity and breather pipe. YB4L-B, CB4L-B	-	X	X	X
Spark arrestor*	Clean. Replace if necessary.	-	X	X	X
Fittings/Fasteners	Tighten when needed.	-	X	X	X
Rear shock absorber*	Check operation/oil leakage. Repair if necessary	-		X	X
V-Belt*	Check for cracks and wear. Replace if necessary.	-			X
Transmission oil*	Replace (warm engine before draining)	SAE 10W30 type SE motor oil	Replace	X	X
Centerstand	Check operation and repair if necessary	-	X	X	X
Steering bearings	Inspect thoroughly and pack moderately	Medium weight wheel bearing grease	X	X	X
Wheel bearings	Check bearings for smooth rotation	Medium weight wheel bearing grease		X	X

*It is recommended that these items be serviced by a Yamaha dealer.