Motocross

GasGas MC 450F 2027

Motocross, 450cc 4T, US version

Verified

Illustration: a GasGas motocross bike, not this exact model.

From the owner’s manual: engine oil capacity 1.20 l, p. 135; coolant 0.95 l, p. 135; front tire 80/100-21 M/C 51M TT, p. 136; rear tire 100/90-19 M/C 57M TT, p. 136. Checked 16 Oct 2026.

Model year on file: 2027 only. Other years are added as their manuals are read.

No CPSC recall found for the 2027 GasGas MC 450F, checked 2026-10-15. Recalls

Spec card PDF

Gearing

4 of 5 filled

Stock front sprocket: 13T; Verified, read off the manual page: Manual p. 135 · checked 2026-09-27 source [1]
Stock rear sprocket: 51T; Verified, read off the manual page: Manual p. 135 · checked 2026-09-27 source [1]
Chain pitch: 520; Verified, read off the manual page: Manual p. 135 · checked 2026-09-27 source [1]
Stock chain links: Not yet verified
Stock final drive ratio: 3.92 : 1; Calculated, not printed: Calculated from the stock sprockets, printed on manual p. 135

Wheels and tires

4 of 4 filled

Front rim: 21 x 1.60; Research level: Spec sheet (research) · checked 2026-09-27 source [2]
Rear rim: 19 x 2.15; Research level: Spec sheet (research) · checked 2026-09-27 source [2]
Front tire: 80/100-21 M/C 51M TT; Verified, read off the manual page: Manual p. 136 · checked 2026-09-27 source [1]
Rear tire: 100/90-19 M/C 57M TT; Verified, read off the manual page: Manual p. 136 · checked 2026-09-27 source [1]

Suspension

6 of 7 filled

Fork: WP XACT AER; Verified, read off the manual page: Manual p. 137 · checked 2026-09-27 source [1]
Fork travel: 310 mm (12.20 in); Verified, read off the manual page: Manual p. 135 · checked 2026-09-27 source [1]
Shock travel: 300 mm (11.81 in); Verified, read off the manual page: Manual p. 135 · checked 2026-09-27 source [1]
Stock fork spring rate: Not yet verified
Stock shock spring rate: 45 N/mm; Verified, read off the manual page: Manual p. 138 · checked 2026-09-27 source [1]
Static sag, bike only: 35 mm (1.38 in); Verified, read off the manual page: Manual p. 138 · checked 2026-09-27 source [1]
Race sag, rider on: 105 mm (4.13 in); Verified, read off the manual page: Manual p. 138 · checked 2026-09-27 source [1]

Fluids and capacities

4 of 4 filled

Engine oil spec: 10W/50 fully synthetic; Verified, read off the manual page: Manual p. 135 · checked 2026-09-27 source [1]
Engine oil capacity: 1.20 l (≈ 40.6 fl oz, converted by MotoXSports); Verified, read off the manual page: Manual p. 135 · checked 2026-09-27 source [1]
Coolant capacity: 0.95 l (≈ 32.1 fl oz, converted by MotoXSports); Verified, read off the manual page: Manual p. 135 · checked 2026-09-27 source [1]
Fuel capacity: 7.9 l (≈ 2.09 gal, converted by MotoXSports); Verified, read off the manual page: Manual p. 136 · checked 2026-09-27 source [1]

Service specs

5 of 6 filled

Fork oil: Fork oil (48601166S1) (SAE 4): right outer assembly 240 ml (8.12 fl. ozUS); left outer assembly 240 ml (8.12 fl. ozUS); right cartridge 380 ml (12.85 fl. ozUS); Verified, read off the manual page: Manual p. 137 · checked 2026-10-16 source [1]
Brake fluid: DOT 5.1; Verified, read off the manual page: Manual p. 150 · checked 2026-10-16 source [1]
Coolant type: COOLANT M3.0, recommended supplier MOTOREX®; antifreeze protection to at least −25 °C (−13.0 °F); Verified, read off the manual page: Manual p. 150 · checked 2026-10-16 source [1]
Fuel octane: Super unleaded (ROZ 95); Verified, read off the manual page: Manual p. 136 · checked 2026-10-16 source [1]
Idle speed: Not yet verified
Valve clearance: Intake at: 20 °C (68.0 °F) 0.10 mm … 0.15 mm (0.0039 in … 0.0059 in); Exhaust at: 20 °C (68.0 °F) 0.12 mm … 0.17 mm (0.0047 in … 0.0067 in); Verified, read off the manual page: Manual p. 134 · checked 2026-10-16 source [1]

Maintenance

3 of 3 filled

Tire pressure (off-road): 1.0 bar (14.5 psi) front and rear; Verified, read off the manual page: Manual p. 136 · checked 2026-09-27 source [1]
Chain slack: 58-61 mm (2.28-2.40 in); Verified, read off the manual page: Manual p. 73 · checked 2026-09-27 source [1]
Spark plug and gap: NGK LMAR9AI-10, gap 1.0 mm; Verified, read off the manual page: Manual p. 134 · checked 2026-09-27 source [1]

Dimensions

3 of 3 filled

Seat height: 956 mm (≈ 37.6 in, converted by MotoXSports); Verified, read off the manual page: Manual p. 135 · checked 2026-09-27 source [1]
Wheelbase: 1493 mm (≈ 58.8 in, converted by MotoXSports); Verified, read off the manual page: Manual p. 135 · checked 2026-09-27 source [1]
Weight (weight without fuel approx.): 103.6 kg (≈ 228 lb, converted by MotoXSports); Verified, read off the manual page: Manual p. 136 · checked 2026-09-27 source [1]

Solid marks are owner's-manual pages; hollow marks are manufacturer web or spec-sheet figures still waiting on a manual page. Last reviewed 2026-10-16. Rows marked not yet verified are blank on purpose.

Buying parts

The stock sizes and specs this bike left the factory with, each with its source. Take them to any shop.

Retailer links below are affiliate links: we may earn a commission, at no cost to you, and it never changes the specs. Affiliate disclosure.

Chain: Chain pitch 520 Owner's manual p. 135520 chains at MotoSport 520 master links at MotoSport
Sprockets: Stock front sprocket 13T Owner's manual p. 135Stock rear sprocket 51T Owner's manual p. 13513T front sprockets at MotoSport 51T rear sprockets at MotoSport
Tires: Front tire 80/100-21 M/C 51M TT Owner's manual p. 136Rear tire 100/90-19 M/C 57M TT Owner's manual p. 136Front tires 80/100-21 at MotoSport Tubes 80/100-21 at MotoSport Rear tires 100/90-19 at MotoSport Tubes 100/90-19 at MotoSport
Engine oil: Engine oil spec 10W/50 fully synthetic Owner's manual p. 135Engine oil capacity 1200 ml (40.6 fl oz) Owner's manual p. 135Engine oil at MotoSport
Coolant: Coolant capacity 950 ml (32.1 fl oz) Owner's manual p. 135Coolant at MotoSport
Suspension springs: Stock shock spring rate 45 N/mm Owner's manual p. 138Suspension at MotoSport

In stock at MotoSport

Prices from MotoSport’s catalog of Oct 19, 2026; check today’s price before you buy.

Front tire, stock size 80/100-21

Rear tire, stock size 100/90-19

Engine oil, stock viscosity 10W-50

Matched on viscosity only. The manual prints: 10W/50 fully synthetic. Check the label for the rest.

Prices and stock from MotoSport's product catalog on Oct 19, 2026; they change, so check the price at MotoSport before you buy. Products are chosen by exact stock size, code or oil viscosity from the specs above, known brands first, then price. We have not tested them.

2 part specs not yet verified; see data coverage.

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Service schedule

57 rows from the owner's manual schedule, pp. 31-33, counted in hours, at these intervals:

After one operating hour
Every 15 operating hours
Every 45 operating hours
Every 90 operating hours
Every 24 months

Check what's due or track it in My Bike. Buying one used? The hours check lists what the schedule calls for by its meter reading.

Gearing calculator

Gearing for this bike

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

Start from a bike's stock gearing

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

Front sprockets 8–16 teeth, rear 34–60. Values outside that range are brought back to the nearest limit.

Setup A — what you run now

Front teeth

Rear teeth

Setup B — what you are thinking about

Front teeth

Rear teeth

Final drive ratio

— — : 1

—

Pull at the wheel—

Top speed—

Ratio change—

A —

B —

Taller · more speed Shorter · more pull

—

Changing the rear sprocket changes the chain length too. The chain length calculator works it out from the chain you have now, with where the axle ends up.

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

What's missing

26 of 31 fields read off a manual page.

Not yet verified (3): chain links, fork spring rate, idle speed.

From a spec sheet, awaiting a manual page (2): front rim, rear rim.

See coverage for every bike

Sources

1
GASGAS Owner's Manual 2027 MC 450F, Item no. 3215291en (06/08/2026); owner-supplied copy from the KTM Group print-on-demand portalpp. 73, 134, 135, 136, 137, 138, 150Manual page, verified. Covers stock front sprocket, stock rear sprocket, chain pitch, front tire, rear tire, fork, fork travel, shock travel, stock shock spring rate, static sag, bike only, race sag, rider on, engine oil spec, engine oil capacity, coolant capacity, fuel capacity, tire pressure (off-road), chain slack, spark plug and gap, seat height, wheelbase, weight (weight without fuel approx.), engine oil figure, as labelled, weight, as labelled, fork oil, brake fluid, coolant type, fuel octane, valve clearance; checked 2026-10-16.
2
GasGas 2027 MC 450F technical specifications (gasgas.com, US)Manufacturer web or spec sheet, research level. Covers front rim, rear rim; checked 2026-09-27.

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

Your manual prints something different? Report a value with the page it is on; every fix is listed in the corrections log.

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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