MotoXSports The Garage

Motocross

Kawasaki KX125

Motocross, 124cc 2T, 2004–2008

Verified

Gearing

5 of 5 filled

Stock front sprocket
13T
Owner's manual p. 1-8, checked 2026-09-26 (source 1)
Stock rear sprocket
51T
Owner's manual p. 1-8, checked 2026-09-26 (source 1)
Chain pitch
520
Owner's manual p. 10-4, checked 2026-09-26 (source 1)
Stock chain links
114
Owner's manual p. 10-4, checked 2026-09-26 (source 1)
Stock final drive ratio
3.923 : 1
Owner's manual p. 1-8, checked 2026-09-26 (source 1)

Wheels and tires

4 of 4 filled

Front rim
21 x 1.60
Owner's manual p. 1-8, checked 2026-09-26 (source 1)
Rear rim
19 x 1.85
Owner's manual p. 1-8, checked 2026-09-26 (source 1)
Front tire
80/100-21 51M
Owner's manual p. 1-8, checked 2026-09-26 (source 1)
Rear tire
100/90-19 57M
Owner's manual p. 1-8, checked 2026-09-26 (source 1)

Suspension

2 of 7 filled

Fork
Not yet verified
Fork travel
300 mm (11.8 in)
Owner's manual p. 1-8, checked 2026-09-26 (source 1)
Shock travel
310 mm (12.2 in)
Owner's manual p. 1-8, checked 2026-09-26 (source 1)
Stock fork spring rate
Not yet verified
Stock shock spring rate
Not yet verified
Static sag, bike only
Not yet verified
Race sag, rider on
Not yet verified

Fluids and capacities

3 of 5 filled

Engine oil spec
Not yet verified
Engine oil capacity
Not yet verified
Coolant capacity
970 ml (32.8 fl oz)
Owner's manual p. 2-18, checked 2026-09-26 (source 1)
Premix ratio
32:1
Owner's manual p. 1-7, checked 2026-09-26 (source 1)
Fuel capacity
8.2 L (2.17 gal)
Owner's manual p. 1-7, checked 2026-09-26 (source 1)

Maintenance

2 of 3 filled

Tire pressure (off-road)
100 kPa (1.0 kgf/cm², 14 psi) front and rear
Owner's manual p. 9-4, checked 2026-09-26 (source 1)
Chain slack
52-62 mm (2.05-2.44 in.)
Owner's manual p. 10-4, checked 2026-09-26 (source 1)
Spark plug and gap
Not yet verified

Dimensions

2 of 3 filled

Seat height
940 mm (37.0 in)
Owner's manual p. 1-7, checked 2026-09-26 (source 1)
Wheelbase
1470 mm (57.9 in)
Owner's manual p. 1-7, checked 2026-09-26 (source 1)
Weight
Not yet verified
Solid marks are owner's-manual pages; hollow marks are manufacturer web or spec-sheet figures still waiting on a manual page. Last reviewed 2026-09-26. Rows marked not yet verified are blank on purpose.

What's missing

17 of 24 fields read off a manual page.

Not yet verified (7): fork, fork spring rate, shock spring rate, static sag, race sag, weight, maintenance.spark_plug.

See coverage for every bike

Tools for this bike

Compare with

Buying parts

The stock sizes and specs this bike left the factory with, each with its source. Take them to any shop. Retailer links will appear here once a store approves MotoXSports.

Chain
Chain pitch 520 Owner's manual p. 10-4Stock chain links 114 Owner's manual p. 10-4
Sprockets
Stock front sprocket 13T Owner's manual p. 1-8Stock rear sprocket 51T Owner's manual p. 1-8
Tires
Front tire 80/100-21 51M Owner's manual p. 1-8Rear tire 100/90-19 57M Owner's manual p. 1-8
Coolant
Coolant capacity 970 ml (32.8 fl oz) Owner's manual p. 2-18

4 part specs not yet verified; see data coverage.

Garage tool 01

Sprocket calculator

Put your current gearing in Setup A and the setup you are considering in Setup B. Everything updates as you type.

Pick a bike to fill both setups with its stock sprockets.

Front sprockets 10–16 teeth, rear 34–60. Values outside that range are brought back to the nearest limit.

Setup A — what you run now
Setup B — what you are thinking about
Final drive ratio

— — : 1

—
Pull at the wheel—
Top speed—
Chain (est.)—
A —
B —
Taller · more speed Shorter · more pull

—

Ratios are exact. The chain figure is an estimate of roughly one link per two teeth of change — confirm against your manual before ordering.

Sources

  1. 1
    Kawasaki KX125/KX250 Motorcycle Service Manual (KX125-M1 to KX125M8F, 2003-2008; KX250-M1 to M2, 2003-2004), Part No. 99924-1298-07, 7th edition; owner-supplied copy, pp. 1-7, 1-8, 2-18, 9-4, 10-4Manual page, verified. Covers stock front sprocket, stock rear sprocket, chain pitch, stock chain links, stock final drive ratio, front rim, rear rim, front tire, rear tire, fork travel, shock travel, coolant capacity, fuel capacity, premix ratio, tire pressure (off-road), chain slack, seat height, wheelbase; checked 2026-09-26.

Always confirm against the manual for your exact year before ordering parts or setting up suspension. Torque specs are deliberately not published here.

My settings

Date / track
Sprockets run
Race sag / free sag
Fork air pressure or spring
Fork clickers (compression / rebound)
Shock clickers (low / high / rebound)
Tire pressures (front / rear)
Notes
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