Motocross · Four stroke
KTM 450 SX-F
KTM's 450 motocross bike. The lightest 450 in the class for most of its life, electric start and a hydraulic clutch long before the Japanese, and the bike the factory teams win on. Sold in Australia from 2007 to 2026, 20 model years.
About the KTM 450 SX-F
The 450 SX F has been the premium 450 since KTM started winning outdoor championships on it. It was the first 450 motocross bike with electric start and a hydraulic clutch as standard, it has always been the lightest or close to it, and the current generation (2023 onwards) has traction control, launch control and a quickshifter through the handlebar map switch. WP suspension with an air fork since 2017.
It suits a fast clubman or A grade rider who wants the lightest, most adjustable 450. It feels sharper and more nervous than a YZ450F, and the air fork divides opinion. Against a Husqvarna FC 450 or GasGas MC 450F it is the same bike with different suspension settings and bodywork.
What changed by year
- 2013 to 2015
- Electric start, hydraulic clutch, linkage rear end. The bikes that started KTM winning in the US. Cheap now and still very good.
- 2016 to 2018
- New generation: lighter engine and frame, WP air fork from 2017. Strong, light, fast. A good used buy.
- 2019 to 2022
- Revised frame and engine, updated air fork, map switch with traction and launch control. The most common 450 SX F on the used market.
- 2023 onwards
- All new frame, engine and bodywork, quickshifter, connectivity for tuning from a phone. The early bikes were criticised for a stiff frame; 2025 onwards revised it. The current bike.
Servicing a 450 SX-F
Oil every 5 to 10 hours depending on how hard it is ridden, filter every second change. It takes about 1.2 litres with a filter and KTM specifies a JASO MA 10W 60 or 10W 50 full synthetic; Motorex is what the dealers use. The hydraulic clutch uses mineral oil, not brake fluid, on most years; check the reservoir cap before topping it up.
Air filter every ride. Valves are shim under bucket and hold their clearances well, but check them at the interval in the table. Plan on a piston around 40 to 50 hours for a race bike. Grease the linkage and swingarm and keep an eye on the air fork pressure before every ride.
Engine hours between jobs: the schedule the Digital Garage tracks for this bike, based on the manual. Racers and hard riders go sooner, as above. Ride in sand or mud and halve the engine ones.
| Job | Every |
|---|---|
| Air filter | 3h |
| Engine oil & filter | 15h |
| Gearbox oil | 15h |
| Valve clearance | 45h |
| Coolant flush | 60h |
Parts that fit a 450 SX-F
JT JTF1901 13T Front Sprocket for KTM 520$30.00 · members $25.50
Hiflofiltro Oil Filter HF652 for KTM$18.00 · members $15.30
Motorex Formula 4 Stroke 10W40 4L$99.95 · members $84.96
Motorex Cross Power 4T 10W60 - 1L$47.50 · members $40.38
Motorex Racing Pro Cross 10W40 4L$154.95 · members $131.71
Motorex 4 Stroke 20W50 4L$79.95 · members $67.96
Motorex Hydraulic Fluid 75-200ml$29.95 · members $25.46
Motorex White Grease 100g$31.95 · members $27.16
Motorex Gear Oil Sae 10W30 1L$29.95 · members $25.46
Motul Gearbox 1L 80W90 Moly$42.90 · members $36.46
Motul Chain Lube Factory Line$29.95 · members $25.46
Motul Parts Clean 840ml$21.99 · members $18.69
Buying a used KTM 450 SX-F
Ask about hours, the last piston and the last valve check. Make sure it starts on the button hot and cold. Check the air fork holds pressure overnight and the hydraulic clutch has a firm lever. Look at the airbox, the linkage bearings and the frame around the shock mount. On the 2023 onwards bikes ask whether the suspension has been revalved, because most fast riders have had it done.
Recent sold prices for each year are on the Marketplace page linked below.
Used KTM 450 SX-Fs for sale
8 listed on the MWMX Marketplace right now.
KTM 450 SX-F known issues
Air fork setup
The WP air fork works well when it is set up and checked every ride, and badly when it is not. Check the pressure and the seals.
Stiff chassis on early 2023 to 2024
Riders found the new frame harsh. Suspension setup helps; the 2025 revisions helped more.
Starter and battery
A lithium battery that does not like sitting flat. Keep it on a tender.
KTM 450 SX-F questions
- How often should I change the oil in a 450 SX F?
- Every 5 to 10 hours depending on how hard it is ridden, with a filter every second change.
- What oil does a KTM 450 SX F take?
- A JASO MA full synthetic, 10W 60 or 10W 50. It takes about 1.2 litres with a filter.
- Is the 450 SX F good for a beginner?
- No. It is a fast, sharp race bike. A 250 SX F or a trail bike is a better first motocross bike.
- 450 SX F or 450 EXC F?
- The SX F is the motocross bike: close ratio gearbox, stiffer suspension, no lights. The EXC F is the registrable enduro bike with a wide ratio box and softer suspension.
Other KTM models
- 50 Junior Adventure
- 50 Mini Adventure
- 50 Senior Adventure
- 50 SX
- 50 SX Factory Edition
- 50 SX Mini
- 60 SX
- 65 SX
- 85 SX
- 105 SX
- 125 EXC
- 125 SX
- 125 XC
- 125 XC-W
- 144 SX
- 150 EXC
- 150 SX
- 150 XC
- 150 XC-W
- 200 EXC
- 200 MXC
- 200 XC
- 200 XC-W
- 250 EXC
- 250 EXC-F
- 250 EXC-F Six Days
- 250 MXC
- 250 SX
- 250 SX-F
- 250 SX-F Factory Edition
- 250 XC
- 250 XC-F
- 250 XC-W
- 250 XCF-W
- 300 EXC
- 300 EXC Six Days
- 300 MXC
- 300 SX
- 300 XC
- 300 XC-W
- 350 EXC-F
- 350 EXC-F Six Days
- 350 SX-F
- 350 XC-F
- 350 XCF-W
- 360 SX
- 380 EXC
- 380 SX
- 400 EXC
- 400 LC4
- 400 MXC
- 400 SX
- 400 XC-W
- 450 EXC
- 450 EXC-F
- 450 MXC
- 450 SX
- 450 SX-F Factory Edition
- 450 XC
- 450 XC-F
- 450 XCF-W
- 500 EXC
- 500 EXC-F
- 500 EXC-F Six Days
- 500 XCF-W
- 505 SX-F
- 505 XC-F
- 520 EXC
- 520 SX
- 525 EXC
- 525 MXC
- 525 SX
- 525 XC
- 530 EXC
- 530 XC-W
- 620 LC4
- 640 LC4 Enduro
- 690 Enduro R
- 690 SMC R
- Freeride 250F
- Freeride 250R
- Freeride 350
- Freeride E-SX
- Freeride E-XC
- SX-E 3
- SX-E 5
- All makes →