250F vs 450: Which Dirt Bike Should You Race?

If you are asking the question, race the 250F. It is legal in more classes, costs $950 to $1,500 less new, and gives away very little weight to the 450, which on Dirt Rider’s dyno makes about 15 more horsepower and close to double the torque. Pick the 450 if you are a bigger or experienced rider, you want to race Open and Vet classes, or you race long, fast off-road and desert courses.

How do a 250F and a 450 compare on paper?

Three pairs from the same makers, using the newest model each one lists as of October 2026. Prices and weights are from the manufacturers. Power is rear-wheel horsepower measured by Dirt Rider on its own Dynojet 250i, and those runs were on 2026 models.

Bike	Engine	Peak power (2026 model)	Peak torque	Weight	MSRP	Rear tire	Piston interval in the manual
2027 Honda CRF250R	249cc	37.8 hp	18.0 lb-ft	234 lb curb	$8,599	100/90-19	15 hours
2027 Honda CRF450R	449.5cc	52.6 hp	33.7 lb-ft	238 lb curb	$10,099	120/90-19	15 hours
2026 Yamaha YZ250F	250cc	39.5 hp	18.4 lb-ft	231 lb wet	$8,899	110/90-19	About 12.5 hours
2026 Yamaha YZ450F	450cc	53.5 hp	32.8 lb-ft	243 lb wet	$10,299	120/80-19	About 12.5 hours
2027 KTM 250 SX-F	249.9cc	41.8 hp	19.7 lb-ft	224 lb, no fuel	$10,699	110/90-19	45 hours
2027 KTM 450 SX-F	449.9cc	56.7 hp	34.5 lb-ft	227 lb, no fuel	$11,649	110/90-19	45 hours

Notes on the table, because the footnotes matter:

• Weight is not measured the same way. Honda’s curb weight and Yamaha’s wet weight include a full tank. KTM quotes weight without fuel (101.5 kg and 103.1 kg). Compare within a brand, not across.
• MSRP excludes destination. Yamaha adds $675 and KTM adds $690 freight. Honda’s prices are from its 2027 model announcement.
• The 2027 CRF450R is a redesign. Honda calls it a “sweeping overhaul”, so the 52.6 hp figure from the 2026 bike may not carry over.
• Tires. Every bike here runs an 80/100-21 front. KTM’s 2027 pages do not list sizes, so the KTM rears are from the 2025 250 SX-F and 2024 450 SX-F owner’s manuals.
• Piston intervals come from the manuals linked in the running-cost section below, and the model years are named there.

2027 Honda CRF250R$8,599

2026 Yamaha YZ250F$8,899

2027 Honda CRF450R$10,099

2026 Yamaha YZ450F$10,299

2027 KTM 250 SX-F$10,699

2027 KTM 450 SX-F$11,649

View as table

Item	Value
2027 Honda CRF250R	$8,599
2026 Yamaha YZ250F	$8,899
2027 Honda CRF450R	$10,099
2026 Yamaha YZ450F	$10,299
2027 KTM 250 SX-F	$10,699
2027 KTM 450 SX-F	$11,649

Source: Honda, Yamaha and KTM, checked October 2026; destination and freight not included

The step up to the 450 costs $1,500 at Honda, $1,400 at Yamaha and $950 at KTM.

How much more power does a 450 make?

A bit over a third more peak power and close to double the torque. Pairing Dirt Rider’s 2026 results by brand:

• Honda: 37.8 hp and 18.0 lb-ft for the CRF250R, 52.6 hp and 33.7 lb-ft for the CRF450R.
• Yamaha: 39.5 hp and 18.4 lb-ft for the YZ250F, 53.5 hp and 32.8 lb-ft for the YZ450F.
• KTM: 41.8 hp and 19.7 lb-ft for the 250 SX-F, 56.7 hp and 34.5 lb-ft for the 450 SX-F.

That is 35 to 39 percent more horsepower and 75 to 87 percent more torque. Other magazines’ dynos read differently, so only compare numbers from the same dyno.

Torque is the number you feel. It is why a 450 pulls out of a corner a gear high and why it bites when your throttle hand is sloppy.

Why is a 450 more tiring and less forgiving?

It is not the scale. The 450 is 4 lb heavier at Honda and 12 lb at Yamaha. It is the engine.

• Everything arrives sooner. More speed down every straight means harder braking, bigger bumps at the end of it and less time to set up the corner. Your arms and legs pay for that every lap.
• The engine fights direction changes. A bigger crank, piston and flywheel spinning in the frame make the bike want to stand up and go straight. The 450 feels heavier in the air and when you lay it into a rut than its weight suggests.
• Mistakes get amplified. Whisky throttle on a 250F is a scare. On a 450 it is often a crash. The same goes for landing on the gas or getting kicked sideways in the whoops.
• It lets you be lazy, until it does not. A 450 will pull you out of a corner you entered badly. That hides poor technique when you are fresh and exposes it when you are tired.

A 250F asks the opposite. You have to keep your momentum, shift more and hold it open longer. That is harder work for the bike and better schooling for the rider, which is why fast riders usually come through the 250 class first.

Which classes can you race on each?

A 250F fits everywhere an adult can race. A 450 does not.

The 2026 AMA rulebook lists the amateur motocross classes by engine size: the 250cc class is 122cc to 250cc, and Open, 14-24, Vet 25+, 30+ and 35+, and Senior 40+ through 60+ are all 122cc to open. It also sets the ages: 14 or older to ride 201cc to 250cc, and 16 or older for 251cc and above.

The MX Sports 2026 national classes, which are the Loretta Lynn’s classes, follow the same shape:

Class	Engine limit	250F	450
250 B, 250 C, 250 Pro Sport and the Limited versions	122-250cc	Yes	No
450 B, 450 C, Open Pro Sport	122cc to open	Yes	Yes
College (18-24), Vet (30+), Senior (40+, 45+), Masters (50+)	122cc to open	Yes	Yes

So a 250F rider can enter 250 C and 450 C on the same day with one bike. A 450 rider gets the 450 class and, if old enough, an age class. For AMA off-road events the rulebook splits bikes the same way: a 250cc class at 201cc to 250cc, and Open at 251cc and up.

Local tracks and off-road series write their own class lists, so read the one you will race. More on picking a class in how to start racing dirt bikes.

Does a 450 cost more to run?

By the book, less than the paddock says.

Engine. Within each brand, the manuals give both sizes the same piston interval:

• Honda’s online manuals for the CRF250R and CRF450R both replace the piston and rings every six races or about 15 hours.
• Yamaha’s 2024 YZ250F and 2021 YZ450F manuals both say every fifth race, about 12.5 hours.
• KTM’s 2025 250 SX-F and 2024 450 SX-F manuals both change the piston at the 45-hour service.

Those are scheduled intervals, not failure points. A 250F raced properly spends most of the lap near the top of the rev range, and a 450 rarely gets there, so many racers find the 250F is the one that needs its top end on time. What riders actually see is in how many hours a top end lasts, and the full schedule is in the maintenance schedule by hours.

Oil. The KTM manuals fill the 250 SX-F with 1.0 liter and the 450 SX-F with 1.2 liters. That is the whole difference.

Tires. Honda and Yamaha fit a wider rear to the 450: 120/90-19 against 100/90-19 at Honda, 120/80-19 against 110/90-19 at Yamaha. Wider rears cost a little more, and a 450’s torque wears them faster.

The bike. $950 to $1,500 more to buy, before destination.

For the rest of a season’s budget, see what it costs to race motocross.

Who should pick which?

• Beginner, any age. 250F. You will crash while you learn, and you want the bike that makes those crashes smaller. You can still enter the 450 C or Vet class on it.
• Returning vet. If you raced a 450 before and are fit, a 450 in the Vet or Senior class makes sense. If it has been ten years, a 250F in the same age class is legal and will tire you less.
• Lighter riders. 250F. There is less rider for the engine to pull, and a 450 is a lot of bike to hold on to.
• Heavier and taller riders. A 450’s torque carries weight out of corners and up hills without living on the clutch. This is the best case for the big bike, as long as the skill is there.
• Motocross. Either, by the points above. Motos are short and the 250 classes are usually the deepest.
• Off-road and grand prix. Both work. The 250F is easier to ride for an hour or more. The 450 is easier on its engine at sustained speed.
• Desert. 450. We race the Honda CRF450X in open desert, and long, fast desert racing is 450 territory. An AMA hare and hound must cover at least 60 miles, much of it at speeds where a 250F is held wide open.

What about a 350 or a 2-stroke?

350. The 2027 KTM 350 SX-F is 349.7cc, 102.4 kg without fuel and $11,449. That puts it between its 250 (101.5 kg) and 450 (103.1 kg) siblings on weight and $200 under the 450. It is over the 250cc limit, so it races 450, Open and age classes. It suits a vet who wants more than a 250F and less than a 450.

2-strokes. Yamaha lists the 2026 YZ250 two-stroke at 227 lb wet and $8,099, lighter and cheaper than the YZ250F. Under the AMA’s 122cc to 250cc wording it fits the 250 class. A 125 is the classic learner’s race bike, and the AMA has a 125cc class for two-strokes only. A 2-stroke has no valve train to service, but its powerband takes more work to ride well.