The "Periodic Maintenance / Lubrication Intervals" schedule is taken directly from a 2001-07 Honda Factory Service Manual. It covers models NSS250, NSS250S, NSS250A AND NSS250AS. Before starting any work, always consult the manual for your scooter's model & year and be sure you know what you're doing.

Reflex Periodic Maintenance / Lubrication Intervals
Item Remarks Spec Initial break-in 1
600 mi
(1000 km)
or 
1 month		 Thereafter every
4,000  mi
(6,400 km)		 Thereafter every
8,000 mi
(12,800 km)		 Thereafter every
12,000 mi
(19,200 km)		 Thereafter every
16,000 mi
(25,600 km)
or 
24 months		 Thereafter every
20,000 mi
(25,600 km)
or 
24 months		 Thereafter every
24,000 mi
(25,600 km)
or 
24 months
Fuel line* Inspect and replace as necessary       I   I   I
Throttle Operation* Inspect       I   I   I
Air cleaner Replace. Service more frequently when riding in unusually wet or dusty areas. There are 6 screws on the cover and 2 screws on the air cleaner element.         R     R
Crankcase breather Drain and clean. Service more frequently when riding in the rain or at full throttle.     C C C C C C
Spark Plug Inspect or Replace. The spark plug is under the plastic access cover as shown in the picture. NGK DPR7EA-9, NGK DPR6EA-9 (for cold climate), NGK DPR7EA-9 (for extended high speed riding) Gap 0.80 - 0.90 mm (0.031 - 0.035")   I R I R I R
Valve Clearance* Inspect and adjust valve clearance when engine is cold   I   I   I   I
Engine oil The red circle in the pop-up picture is the 17mm drain plug. The green circle is the oil filler. Replace with Honda GN4 p-stroke oil or equivalent API service classification SG or higher. JASO T 903 standard: MA. SAE 10W-30. R R R R R R R
Engine oil strainer screen* Clean       C   C   C
Engine idle speed* Inspect   I I I I I I I
Radiator coolant Inspect and replace every 2 years.       I   I   R
Cooling system* Inspect       I   I   I
Secondary air supply system* Inspect       I   I   I
Evaporative emission control system* Inspect. California model only         I     I
Drive belt* Check for cracks and wear. Replace every 10K miles. Inspect every 8K miles after replacement.       I R   I R
Belt case air cleaner Clean     C C C C C C
Final drive oil* Replace every 2 years. The red circle in the pop-up picture is the 12mm drain plug. The green circle is the 12mm bolt for the oil fill. Hypoid gear oil #90              
Brake fluid Inspect level and replace every 2 years or at the indicated mileage DOT 4 brake fluid   I I R I I R
Brake pad wear Inspect and replace as needed     I I I I I I
Brake system Inspect   I   I   I   I
Brake light switch* Inspect       I   I   I
Brake lock operation* Inspect   I I I I I I I
Headlight aim* Inspect       I   I   I
Clutch shoe wear** Inspect and replace as needed     I I I I I I
Side stand Inspect       I   I   I
Suspension* Inspect       I   I   I
Nuts, bolts, fasteners* Inspect   I   I   I   I
Wheels / Tires** Inspect. Front - 25 psi. Rear - 29 psi (36 psi max).       I   I   I
Steering Bearings** Inspect   I   I   I   I

* It is recommended that these items be serviced by a Honda dealer, unless the owner has proper tools and service data, and is mechanically qualified.
 

** In the interest of safety, we recommend these items to be serviced only by your local Honda scooter dealer.
 

Note:
For further odometer readings, repeat the frequency interval established here.