MotoXSports The Garage

Motocross

Kawasaki KX450F

Motocross, 449cc 4T, 2006–2008

Verified

Gearing

4 of 5 filled

Stock front sprocket
13T
Owner's manual p. 1-9, checked 2026-09-25 (source 1)
Stock rear sprocket
50T
Owner's manual p. 1-9, checked 2026-09-25 (source 1)
Chain pitch
520
Owner's manual p. 2-34, checked 2026-09-25 (source 1)
Stock chain links
Not yet verified
Stock final drive ratio
3.85 : 1
Calculated from the stock sprockets

Wheels and tires

4 of 4 filled

Front rim
21 x 1.60
Owner's manual p. 1-9, checked 2026-09-25 (source 1)
Rear rim
19 x 2.15
Owner's manual p. 1-9, checked 2026-09-25 (source 1)
Front tire
90/100-21 57M
Owner's manual p. 1-9, checked 2026-09-25 (source 1)
Rear tire
120/80-19 63M
Owner's manual p. 1-9, checked 2026-09-25 (source 1)

Suspension

2 of 7 filled

Fork
Not yet verified
Fork travel
315 mm (12.4 in)
Owner's manual p. 1-9, checked 2026-09-25 (source 1)
Shock travel
315 mm (12.4 in)
Owner's manual p. 1-9, checked 2026-09-25 (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

2 of 5 filled

Engine oil spec
Not yet verified
Engine oil capacity
1200 ml (40.6 fl oz)
Owner's manual p. 1-8, checked 2026-09-25 (source 1)
Coolant capacity
Not yet verified
Premix ratio
Not yet verified
Fuel capacity
7.2 L (1.90 gal)
Owner's manual p. 1-8, checked 2026-09-25 (source 1)

Maintenance

1 of 3 filled

Tire pressure (off-road)
Not yet verified
Chain slack
Not yet verified
Spark plug and gap
NGK CPR8EB-9
Owner's manual p. 1-8, checked 2026-09-25 (source 1)

Dimensions

2 of 3 filled

Seat height
965 mm (38.0 in)
Owner's manual p. 1-8, checked 2026-09-25 (source 1)
Wheelbase
1485 mm (58.5 in)
Owner's manual p. 1-8, checked 2026-09-25 (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 2026-09-25. Rows marked not yet verified are blank on purpose.

What's missing

14 of 25 fields read off a manual page.

Not yet verified (11): chain links, fork, fork spring rate, shock spring rate, static sag, race sag, engine oil spec, coolant capacity, weight, maintenance.tire_pressure, maintenance.chain_slack.

See coverage for every bike

Tools for this bike

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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. 2-34
Sprockets
Stock front sprocket 13T Owner's manual p. 1-9Stock rear sprocket 50T Owner's manual p. 1-9
Tires
Front tire 90/100-21 57M Owner's manual p. 1-9Rear tire 120/80-19 63M Owner's manual p. 1-9
Engine oil
Engine oil capacity 1200 ml (40.6 fl oz) Owner's manual p. 1-8

5 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 KX450F Motorcycle Service Manual (KX450D6F-D8F, 2006-2008); owner-supplied copy, pp. 1-8, 1-9, 2-34Manual page, verified. Covers stock front sprocket, stock rear sprocket, chain pitch, front tire, rear tire, front rim, rear rim, fork travel, shock travel, engine oil capacity, fuel capacity, seat height, wheelbase, spark plug and gap; checked 2026-09-25.

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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