KYMCO Mongoose 90S Service Specs: Part Numbers and Intervals

Michal B., KYMCO parts specialist

This is the service sheet for the KYMCO Mongoose 90S (4-stroke single, air cooled, 89.9 cc, carburetted, automatic). It lists the battery, spark plug, filters, belt and the rest, each figure with the genuine KYMCO part number for the model years in our catalog (2016, 2018-2022) and the diagram the part is drawn on. The figures are KYMCO service data from the KYMCO Mongoose 70 / 90 service manual. When this page and your own manual disagree, the manual wins.

What to know before you order

The Mongoose 90S shares the 70S's CR7HSA plug, YTX5L-BS battery and washable oil screen, with a 90 cc engine and larger tires (18 x 7-8 front, 18 x 9-8 rear). Its service runs by the calendar: oil every six months, the plug checked every three, the air filter cleaned every three. The tires run at 3.6 psi.

Mongoose 90S service specs at a glance

Item Spec Genuine part number Diagram
Battery
all models 		12 V 4 Ah 31500-KNBN-92A
YTX5L-BS 		F11 Battery
Spark plug
all models 		gap 0.6-0.7 mm 98056-5771R-00
CR7HSA 		E02 Head Cover ● Cylinder Head Cylinder
Engine oil 0.7 L at an oil change, 0.8 L dry figure only
Oil filter
all models 		washable strainer screen behind the 30 mm cap 15421-1G07-001
Oil Filter Screen 		E04 Right Crankcase Cover
Tires front 18 x 7-8, rear 18 x 9-8; 3.6 psi 42710-ABC9-M00
Rear Tire Assembly (AT18X9.50-8Pr T/l) (2016, 2018-2022)
44710-ABC9-M00
Front Tire Assembly (AT19X7 R8 2Pr T/l) (2016, 2018-2022) 		F08 Rear Wheel

For reference: confirm the number on your own model year's diagram before ordering. Part numbers checked against our catalog on 2026-09-24.

Mongoose 90S maintenance intervals

Whichever comes first, distance or time. The first service is the one riders skip and the one that matters most on a new or rebuilt engine.

Item Interval
Engine oil replace at 1 month, then every 6 months
Spark plug check at 1 month, then every 3 months
Air filter clean every 3 months
Valve clearance check at 1 month, then every 6 months

Torque for the parts you replace

Clean, dry threads unless the row says otherwise. Aluminium cases strip long before a steel bolt complains, so use a torque wrench on the drain bolt and the plug.

Fastener N·m ft-lb
Spark plug 12 8.9
Engine oil drain plug 25 18
Oil strainer screen cap 15 11
Drive face nut 60 44
Wheel nuts 45 33
Rear axle nuts 70 52

Every Mongoose 90S part, drawn on its factory diagram: KYMCO Mongoose 90S parts diagrams.

Which model year do I have?

The year decides which number is yours where a row lists more than one. Decode your VIN with the VIN lookup, or read the model code on the frame plate, then open that year's diagrams from the model list.

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