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Hyosung · Two-stroke single, premix, CVT belt drive

SF (49 cc)

Library entry covers 2005-2011

17 factory 47 guideline

Published source

Hyosung SF 50 owner's manual, Periodic maintenance printed p.19 (ManualsLib)

Factory owner's handbook. Covers Hyosung SF 50 owner's manual (ManualsLib copy); no model year confirmed on the pages read.

64 items for a 2011 model, grouped by interval the way a factory chart is laid out.

How this bike is built (what the schedule is based on)

Engine cycle: Two-stroke
Engine lubrication: Two-stroke premix (oil in fuel)
Oil filtration: None (no filter)
Valve gear: None (two-stroke porting)
Ignition: Electronic (CDI / transistor / ECU)
Charging: Alternator / stator with rectifier
Battery: Wet cell (flooded lead-acid, needs topping up)
Fuel system: Single carburetor
Cooling: Air / oil cooled
Primary drive: Gear or chain inside engine, shares engine oil
Gearbox oil: Separate gearbox oil
Clutch control: Automatic or semi-automatic
Final drive: Belt CVT, scooter automatic
Front suspension: Telescopic fork
Rear suspension: Swingarm, single shock / cantilever
Front brake: Disc, hydraulic
Rear brake: Drum (or band / belt rim)
Wheels: Cast / alloy, tubeless
Sidecar: No sidecar

Maintenance schedule

2011 Hyosung SF (49 cc)

On the road: every 200 km

1 item

Check two-stroke oil tank / carry premix oil

Pre-ride / on the road

Guideline

Running a two-stroke out of oil seizes it. Injection bikes: check the tank. Premix: carry oil and a measure.

On the road: every 500 km

2 items

Check lights, horn, brake light switches

Pre-ride / on the road

Guideline
Check tire pressures

Pre-ride / on the road

Guideline

Every 1,600 km or 6 months

2 items

Adjust rear drum brake and rod / cable linkage

Brakes

Guideline
Inspect tire tread, sidewalls and date codes

Wheels and tires

Guideline

Every 3,000 km or 12 months

1 item

Replace spark plugs (two-stroke)

Engine

Guideline

Every 3,000 km

1 item

Air cleaner (clean)

Fuel and air

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Clean every 3,000 km.

Every 4,000 km

11 items

Chassis bolts and nuts (inspect)

Engine

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Inspect at 1,000 km and every 4,000 km.
Engine bolts and nuts (tighten)

Engine

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Tighten at 1,000 km and every 4,000 km.
Engine hose (inspect)

Engine

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Inspect at 1,000 km and every 4,000 km; replace every 2 years.
Spark plug (clean)

Engine

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Clean at 1,000 km and every 4,000 km.
Carburetor (inspect)

Fuel and air

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Inspect at 1,000 km and every 4,000 km.
Steering (inspect)

Front end

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Inspect at 1,000 km and every 4,000 km.
Brake (inspect)

Brakes

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Inspect at 1,000 km and every 4,000 km.
Brake hose and cable (inspect)

Brakes

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Inspect at 1,000 km, every 4,000 km and every 8,000 km.
Brake lever (grease)

Brakes

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Grease at 1,000 km and every 4,000 km.
Tire (inspect)

Wheels and tires

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Inspect at 1,000 km and every 4,000 km.
Throttle cable (lubricate with motor oil)

Controls and cables

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Motor oil at 1,000 km and every 4,000 km.

Every 5,000 km or 12 months

9 items

Check throttle cable(s) free play and return

Fuel and air

Guideline
Clean fuel tap filter / sediment bowl

Fuel and air

Guideline
Adjust automatic / semi-automatic clutch

Primary and gearbox

Guideline
Check steering head bearing adjustment

Front end

Guideline
Inspect fork seals, stanchions and fork boots

Front end

Guideline
Check footrests, pegs, rear brake and gear lever pivots

Rear suspension and frame

Guideline
Grease and check center / side stand and springs

Rear suspension and frame

Guideline
Check brake pads and discs

Brakes

Guideline
Check wheel bearings for play

Wheels and tires

Guideline

Every 5,000 km or 2 years

1 item

Decarbonize exhaust ports, pipes and baffles

Engine

Guideline

Two-strokes coke up the exhaust port and muffler baffles; power falls off gradually.

Every 6,500 km or 12 months

3 items

Inspect, clean and gap spark plugs

Engine

Guideline
Inspect CVT drive belt, rollers / sliders and clutch shoes

Final drive

Guideline

Typical scooter interval. Your owner's manual figure governs; check belt width against the service limit.
Lubricate brake cam spindles, check linings and drums

Brakes

Guideline

Every 8,000 km

3 items

Drive belt (inspect)

Engine

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Inspect every 8,000 km.
Spark plug (replace)

Engine

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Replace every 8,000 km.
Throttle grip (grease)

Engine

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Grease every 8,000 km.

Every 9,500 km or 12 months

7 items

Clean / inspect air filter

Fuel and air

Guideline

Mesh or oiled foam: clean and re-oil. Paper: blow out or replace. Some very early machines have no filter at all.
Clean carburetor float bowl(s), check float level and jets

Fuel and air

Guideline

Ethanol fuel varnishes old carbs quickly in storage.
Check charging voltage and regulator / cut-out

Ignition and electrics

Guideline
Check swingarm bushes for play

Rear suspension and frame

Guideline
Inspect rear shocks for leaks and damping

Rear suspension and frame

Guideline
Lubricate control cables and lever pivots

Controls and cables

Guideline
Lubricate speedometer / tachometer cables, check drive

Controls and cables

Guideline

A dry speedo cable whips the needle and eventually kills the instrument.

Every 16,000 km or 2 years

2 items

Compression test (or leak-down)

Engine

Guideline
Change gearbox oil

Primary and gearbox

Guideline

Every 19,500 km or 2 years

3 items

Replace air filter element

Fuel and air

Guideline
Clean and grease rear suspension linkage

Rear suspension and frame

Guideline
Grease swingarm pivot

Rear suspension and frame

Guideline

Every 19,500 km or 3 years

1 item

Replace CVT drive belt

Final drive

Guideline

Typical scooter interval, or sooner if the belt is cracked, glazed or below its width limit.

Every 20,000 km or 2 years

1 item

Steering stem bearing (grease)

Front end

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Grease every 2 years or every 20,000 km.

Every 24,000 km or 3 years

1 item

Change fork oil

Front end

Guideline

Some early telescopic forks are grease filled or use very small oil quantities. Check your manual.

Every 24,000 km

1 item

Replace brake linings / skim drums (wear based)

Brakes

Guideline

Every 25,500 km or 4 years

1 item

Replace spark plugs

Engine

Guideline

Every 32,000 km or 4 years

2 items

Repack / replace steering head bearings

Front end

Guideline

Many old machines use loose balls in cups and cones. Taper roller conversions are common.
Repack / replace wheel bearings

Wheels and tires

Guideline

Cup-and-cone and taper roller hubs need periodic repacking and adjustment.

Every 40,000 km or 6 years

1 item

Replace swingarm bushes / bearings

Rear suspension and frame

Guideline

Every 48,500 km or 6 years

1 item

Rebuild forks: seals, bushes, springs

Front end

Guideline

Every 6 months

1 item

Clean battery terminals, check charge and strap

Ignition and electrics

Guideline

Every 2 years

4 items

Engine hose (replace)

Engine

Factory

Factory: Periodic maintenance (printed p.19), columns first 1,000 km, every 4,000 km and every 8,000 km; more frequent maintenance for severe use. Replace every 2 years.
Inspect wiring, bullet connectors and ground points

Ignition and electrics

Guideline
Inspect frame, welds and lugs for cracks

Rear suspension and frame

Guideline
Replace brake fluid

Brakes

Guideline

Every 4 years

3 items

Replace fuel lines

Fuel and air

Guideline

Old rubber and modern ethanol fuel do not mix well.
Inspect brake hoses; replace old rubber

Brakes

Guideline
Rebuild calipers and master cylinders (seals)

Brakes

Guideline

Every 6 years

1 item

Replace tires on age (regardless of tread)

Wheels and tires

Guideline

Guideline lines: Intervals here are general guidelines for the machine's era and layout, compiled for this app. They are not factory manual figures. Check your workshop manual, and edit any interval in the bike's Schedule tab.