Kawasaki KX250 Top Speed and Specs, Including the 1999 Two-Stroke
Last updated on October 19th, 2026 at 03:31 am
Kawasaki does not publish a top speed for the KX250. The figure most sites repeat, about 75 mph, comes from a 2022 Dirt Bike Vault test that SlashGear reported.
Kawasaki’s own service manuals show why that number is soft. At stock gearing, 75 mph in fifth gear needs roughly 12,500 to 13,000 rpm on the four-strokes and about 9,250 rpm on the 1999 two-stroke, so the rev limit and the terrain decide it, not the model year.
How fast is a Kawasaki KX250?
The only traceable test figure is about 75 mph for a stock four-stroke. Other pages quote anything from 70 to 82 mph without saying how they measured, so treat the whole range as an estimate that moves with rider weight, gearing, altitude and surface.
Kawasaki gears the KX250 for acceleration out of corners on a motocross track. The stock 13-tooth front and 50-tooth rear sprockets on the four-strokes are short gearing, which is why fifth gear runs out of revs well before a desert or dual-sport bike would.
| Source | Top speed figure | How solid it is |
|---|---|---|
| Kawasaki spec sheets (2021, 2024, 2025) | None published | Official, but silent on speed |
| Dirt Bike Vault test (2022), as reported by SlashGear | About 75 mph | One tested report; original page unavailable when checked |
| Spec databases and shop pages | 70 to 82 mph | No method given, not used here |
| Gearing math from Kawasaki service manuals | rpm needed for each mph | Calculated below, depends on the rev limit |
What the gearing says: rpm needed for 75 mph
Road speed comes from three ratios and the tire. Multiply the primary reduction, the gear you are in and the sprocket ratio, divide engine rpm by that total, then multiply by the tire’s rolling circumference.
The service manuals list every ratio, so the arithmetic is checkable. Honda publishes similar gear data for its CRF250R top speed and gearing, which makes a fair comparison.
| Generation | Primary | 1st | 2nd | 3rd | 4th | 5th | Final (front/rear teeth) | Overall, 5th |
|---|---|---|---|---|---|---|---|---|
| 1999–2000 KX250 two-stroke (M1/M2) | 3.000 | 1.800 | 1.437 | 1.176 | 1.000 | 0.869 | 3.769 (13/49) | 9.832 |
| 2006–2008 KX250F (T6F–T8F) | 3.350 | 2.142 | 1.785 | 1.444 | 1.200 | 1.045* | 3.692 (13/48) | 12.931 |
| 2013 KX250F (ZD) | 3.350 | 2.142 | 1.750 | 1.444 | 1.235 | 1.045 | 3.846 (13/50) | 13.470 |
| Current-generation KX250 (Kawasaki Europe) | 3.350 | 2.077 | 1.688 | 1.438 | 1.235 | 1.045 | 3.846 (13/50) | 13.46 (calculated) |
Those ratios, plus the rear tire size from each manual, give the table below. A tire’s rolling circumference is taken from its nominal size, so a worn or squashed tire rolls a little smaller and real speed comes out a touch lower.
Read the last column as a reality check. If your engine cannot reach that rpm in fifth gear, it cannot reach 75 mph at stock gearing. The manuals and spec sheets we opened list no rev limit.
| Generation | Rear tire | mph per 1,000 rpm in 5th | rpm needed for 75 mph in 5th |
|---|---|---|---|
| 1999–2000 two-stroke | 110/90-19 | 8.11 | About 9,250 |
| 2006–2008 KX250F | 100/90-19 | 6.00 | About 12,500 |
| 2013 KX250F | 100/90-19 | 5.76 | About 13,000 |
| Current-generation KX250 | 110/90-19 | 5.92 | About 12,700 |
That is why a four-stroke needs a healthy top end and clean fuel to touch 75 mph, while the two-stroke gets there at far lower revs. A claim of 80-plus mph on a stock four-stroke means roughly 13,500 to 14,000 rpm in fifth on a 13/50 setup.
Check that arithmetic against your own sprockets in the calculator below before you believe or repeat any top-speed number.
KX250 speed-by-gear calculator
Check speed by gear for your KX250
Based on the gear ratios in the Kawasaki service manuals cited above and the nominal tire diameter. It is a theoretical figure with no wheel slip or drag, and no redline is published in those manuals.
The calculator uses gear ratios from the Kawasaki service manuals listed above, with a nominal tire diameter (rim plus two sidewalls). It ignores wheel slip, tire squash and drag, so real speed is a little lower than the number shown.
Kawasaki lists no redline in those manuals, so enter the rpm your bike actually pulls. For other vehicles, use our free off-road calculators.
How sprocket changes move KX250 speed
Gearing is the one top-speed lever you control. A taller ratio raises the speed you reach at a given rpm but dulls acceleration, and a shorter ratio does the opposite.
On a 13/50 setup, one tooth on the front sprocket moves the ratio as much as about 3.8 teeth on the rear. That is why most riders change the rear first.
| Change from stock 13/50 | Overall ratio | Speed at the same rpm | Feel |
|---|---|---|---|
| Front 13 → 14 teeth | Lower | About 7.7% higher | Taller, slower pull |
| Front 13 → 12 teeth | Higher | About 7.7% lower | Shorter, quicker pull |
| Rear 50 → 49 teeth | Lower | About 2% higher | Slightly taller |
| Rear 50 → 51 teeth | Higher | About 2% lower | Slightly shorter |
After any sprocket change, recheck chain slack. Kawasaki’s manuals give 2.05 to 2.44 in. (52 to 62 mm) for the 1999–2000 KX250 and 2.0 to 2.3 in. (52 to 58 mm) for the 2013 KX250F; use the figure in your own manual.
A chain stretched past its limit is worn out. The 1999–2000 manual lists a 20-link length of 317.5 to 318.2 mm new and 323 mm (12.72 in.) as the service limit.
Kawasaki KX250 specs by generation
Kawasaki sold a two-stroke KX250 in the US until the 2007 model year, per Dirt Rider. The four-stroke KX250F took over, and Kawasaki dropped the F from the name for 2021.
The table below uses each manufacturer source’s own weight basis, so compare weights only within a row. Specs change between years, so check the spec sheet or manual for yours.
| Model | Engine | Fuel system | Tank | Weight (as listed) | Rear tire |
|---|---|---|---|---|---|
| 1999–2000 KX250 | 249 cc two-stroke, 66.4 × 72.0 mm, reed valve | Keihin PWK38S carburetor | 2.2 gal (8.2 L) | 214 lb (97 kg) dry | 110/90-19 |
| 2006–2008 KX250F | 249 cc four-stroke, 13.5:1 | Keihin FCR37 carburetor | 1.9 gal (7.2 L) | 204 lb (92.5 kg) dry | 100/90-19 |
| 2013 KX250F | 249 cc four-stroke, 13.8:1 | Fuel injection, Keihin 43 | 1.6 gal (6.1 L) | 234.2 lb (106.2 kg) curb | 100/90-19 |
| 2021 KX250 | 249 cc, 78.0 × 52.2 mm, 14.1:1 | Fuel injection, 44 mm | 1.64 gal | 236.5 lb with fuel | 100/90-19 |
| 2024 KX250 | 249 cc, 78.0 × 52.2 mm, 14.1:1, Launch Control Mode | Fuel injection, 44 mm | 1.64 gal | 237.7 lb with fuel | 110/90-19 |
| 2025 KX250 | 249 cc, 14.0:1, Power Modes, traction control (KTRC), launch control, hydraulic clutch | Fuel injection, 44 mm | 1.64 gal | 240.7 lb with fuel | 110/90-19 |
Every model in the table uses a five-speed gearbox with a wet multi-disc clutch and chain final drive, according to the same sources. The 2025 sheet adds handlebar-controlled power modes and smartphone connectivity.
Seat height is 37.2 to 37.8 in. across these models, and fuel tanks hold only 1.6 to 2.2 gallons.
1999 KX250 two-stroke: specs and top speed
Kawasaki’s KX250 M1 and M2 manual covers the 1999 and 2000 models. It gives no top speed, but its gearing puts 75 mph in fifth at about 9,250 rpm, so the gearing does not rule out 70 to 75 mph for a healthy bike. We found no tested figure for it.
Treat a seller’s “80 mph” claim with caution unless they can show the sprocket counts, engine work and a GPS reading. Aftermarket pipes, reeds and porting only work with the right jetting and fresh silencer packing.
| Item | 1999–2000 KX250 (manual value) |
|---|---|
| Engine | 249 cc liquid-cooled two-stroke, 66.4 × 72.0 mm, piston reed valve |
| Carburetor | Keihin PWK38S |
| Fuel mix | 32:1 gasoline to oil |
| Spark plug | NGK BR8EIX |
| Starting | Primary kick |
| Transmission oil | SAE 10W-40, 0.85 L (0.90 US qt) |
| Stock final drive | 13 front / 49 rear teeth |
| Tires | 80/100-21 front, 110/90-19 rear |
| Tank / dry weight | 2.2 US gal (8.2 L) / 214 lb (97 kg) |
After 25-plus years, two identical bikes can feel very different. Count the sprocket teeth before judging performance, because previous owners often changed them.
Jetting depends on altitude and temperature, so a bike that runs well in one place may run lean in another. Check the carburetor settings in the manual and re-jet for your conditions.
Checking a used 1999 KX250 before you buy
- Cold start: a well-jetted bike should not need endless kicking.
- Compression: weak kick resistance points to worn rings or piston.
- Shifting: missed shifts under load can mean expensive gearbox work.
- Clutch: slipping in the higher gears can look like a weak top end.
- Expansion chamber: dents near the header hurt power.
- Cooling: bent radiator cores, stains or coolant loss need attention.
- Chain and sprockets: hooked teeth or a chain stretched past 323 mm over 20 links mean a new set.
- Frame and subframe: look for cracks, twist or rough weld repairs.
- Suspension linkage: dry, notchy bearings make the rear harsh and unstable.
If you test top speed, do it only on private land or at an approved riding area, in full gear, with a warm engine and plenty of room to slow down.
Is the KX250 street legal?
No. Kawasaki’s own service manual calls the KX250F “designed for competition use only,” and the bike comes without road equipment such as lights and mirrors. Keep it to tracks, private land and approved off-road areas.
Some states also require an OHV registration or sticker for public riding areas, so check your state agency. For places to ride, see our guides to dirt bike trails in Pennsylvania and Florida.
How to measure your own KX250 top speed safely
- Pick a closed course or private land with at least a long straight and a long runoff. Wear a helmet, goggles, boots, gloves and body armor.
- Check the chain slack, sprocket teeth and tire pressure against your manual. Kawasaki lists 14 psi (100 kPa) for the 2006–2008 KX250F.
- Warm the engine fully. Mount a GPS speedometer or phone app where you can read it.
- Make one run in each direction and average them, which cancels most wind effect. Note the rpm you reach in fifth.
- Compare that rpm with the calculator. If the rpm matches but the mph does not, your tire size or sprocket count is not what you entered.
FAQs
Kawasaki does not publish one. The only traceable test figure is about 75 mph from a 2022 Dirt Bike Vault test reported by SlashGear, and it varies with gearing, rider weight and surface.
On stock gearing in fifth, about 9,250 rpm on the 1999 two-stroke and about 12,500 to 13,000 rpm on the KX250F four-strokes, calculated from the Kawasaki service manual ratios.
Kawasaki gives no figure. With the manual’s 13/49 gearing it needs about 9,250 rpm for 75 mph in fifth, so the gearing does not rule out 70 to 75 mph, but no tested figure exists that we could find.
Kawasaki sold a two-stroke KX250 in the US through the 2007 model year. The current KX250 (called KX250F through 2020) is a fuel-injected four-stroke.
The 2024 and 2025 models use an 80/100-21 front and a 110/90-19 rear tire. The 2021 model and the older KX250F models use a 100/90-19 rear.
No. Kawasaki’s service manual says the KX250F is designed for competition use only. Ride it on tracks, private land and approved off-road areas.
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I'm Suryashankar Dasgupta, the founder of Off-Road Handbook. I've been off-roading for years in the USA, including California and Texas, and have ridden mountain and desert terrain abroad. I've also driven a Jeep Compass for more than seven years, so I know the day-to-day side of Jeep ownership first-hand, from the Uconnect screen to the warning lights. Every guide here is researched from manufacturer owner's manuals, NHTSA recall and service-bulletin records and other trusted sources, checked against them before it is published, and corrected when we find a mistake. You can read how we work in our editorial policy: https://offroadhandbook.com/editorial-policy/
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