KTM 300 SX specifications
KTM · Motocross
Dirt Bike Magazine says the sharp power delivery has ripple effects in handling, which "tend to be harsh and magnify any negative traits", and that the owner has to learn to ride a little differently and commit to a more demanding maintenance schedule.
It reports that in the aggressive map the 2023 model hit hard, signed off early and left riders a little frazzled, that the service manual asks for a piston replacement every 15 hours, and that some factory Supercross riders still prefer the previous year's stiff frame. The report adds that a white-light mode limits power-valve throw to 80 percent of its full travel.
KTM 300 SX
| Specification | Value |
|---|---|
| Model year | 2027 |
| Displacement | 293.2cc |
| Bore x stroke | 72x72 mm |
| Transmission | 5-speed |
| Ground clearance | 354 mm (13.94 in) |
| Weight without fuel | 99.4 kg |
| Starting MSRP | $9,899 |
| Class | Motocross |
| Engine | 1-cylinder, 2-stroke engine |
| Fuel system | Vitesco Technologies EMS |
| Final drive | 520, Non-sealed |
| Front suspension | WP XACT-USD (AER), Ø 48 mm |
| Front suspension travel | 310 mm |
| Rear suspension | WP XACT Monoshock with linkage |
| Rear suspension travel | 300 mm |
| Front brake | Disc brake |
| Seat height | 958 mm |
| Fuel capacity | 1.9 gal |
| Frame | Central double-cradle-type 25CrMo4 steel |
| Destination charge | $690 |
The same magazine points out that the last 300 in the US was in 2002, when it coexisted with a 380 SX, and that for 21 years afterwards KTM's biggest motocross two-stroke was the 250 SX.
What the 2025 update added
Total Motorcycle says the 300 SX has an engine weight of 52.6 lb (23.9 kg) and calls it a new choice of weapon in the MX Open category for racers who want maximum power at the least possible weight. Dirt Bike Magazine adds that the electronic power valve is self-contained on the side of the cylinder and does away with the remote servos and cables used on earlier versions.
The 300 SX uses a five-speed gearbox, a 310 mm WP XACT air fork and a 300 mm XACT shock, with the same 958 mm seat and 354 mm ground clearance as the 250 SX. It is 293.2cc, or 44 cc more than the 250. The price is $250 higher.
Against the 250 SX
The 300 costs $9,899 to the 250's $9,649, and the bikes share weight and chassis. The extra 44 cc buys torque low in the range, which the 250 does not have, at the cost of the harder hit Dirt Bike Magazine describes.
The 300 SX comparison includes the service demands reported in Dirt Bike Magazine’s dated test. Its piston interval refers to that tested edition and its service schedule; check the manual for the exact model year and operating conditions.
300 SX against the 250 SX and 450 SX-F
KTM's own 250 SX and KTM 450 SX-F use the same chassis. So they are the direct comparison.
KTM 300 SX — specification referenceKTM · Motocross
The 300 SX brings back a big-bore two-stroke to KTM's US motocross line for the first time since 2002, and Dirt Bike Magazine says it demands more maintenance than a four-stroke. KTM asks $9,899 before destination.
Where the 300 SX and the 250 SX differ, from the two KTM listings
- Model-year range
- 2025–2027
- Compared editions
- 3
- Specification entries
- 21
- Entries that differ
- 0
2027 KTM 300 SX questions
How often does the KTM 300 SX need a new piston?
Dirt Bike Magazine reports the service manual asks for a piston replacement every 15 hours, not an inspection, which is a shorter interval than most four-strokes.
Is the KTM 300 SX easy to ride?
Dirt Bike Magazine says its sharp power delivery magnifies negative traits in handling and calls a powerful two-stroke a bit of a toggle switch next to a four-stroke.
What does the 300 SX power-valve mode do?
Dirt Bike Magazine says that with the white light on, power-valve throw is limited to 80 percent of its full travel.
The 300 SX suits an experienced motocross rider who wants an open-class two-stroke and accepts a piston every 15 hours as the price. A newer rider will find the 250 gentler.
Why the larger two-stroke is a separate motocross choice
The 300 SX is the 293.2cc two-stroke motocross option in this comparison. It is not the 300 XC or XC-W with a different decal. Start with the intended riding and event requirements, then check the SX's fuel system, gearing and equipment in the correct handbook. An engine-capacity comparison cannot establish road registration or trail-access eligibility.
The listed seat is 958 mm and the tank 1.9 gallons. Seat height should be tried with the rider's boots and the suspension set for the rider; the catalog measurement alone does not establish a suitable fit. The fuel figure describes capacity rather than how long a moto will last. Use actual consumption from the intended riding before deciding whether an additional fuel stop is needed.
At $9,899, the 300 is $250 above the listed 250 SX. A buyer choosing between them should therefore consider the desired engine response and the ability to use it through a complete session, rather than treating the modest base-price gap as a reason to buy more displacement automatically. Service requirements, tires and crash damage remain part of inspecting either competition bike.
Other models in this reference: KTM 300 XC, KTM 250 XC.