Motocross
Yamaha YZ250
The last of the Japanese 250 two strokes still in production, and the one that has barely changed because it never needed to. Cheap to run, easy to fix, and still fast. Sold in Australia from 1990 to 2026, 37 model years.
About the Yamaha YZ250
The YZ250 two stroke is a legend for a reason. The engine and aluminium frame have been essentially the same since 2006, and while that sounds like a criticism it is why the bike is so loved: every part is cheap, every mechanic knows it, and a top end is a Saturday morning job in the shed. The KYB SSS fork was added in 2006 and remains one of the best off the shelf forks on any dirt bike.
It suits a rider who wants a fast, light, simple bike for club racing, vet class or weekend blasting. Compared to a KTM 250 SX it is heavier and less refined, and it lacks the KTM electric start, but it is a fraction of the price used and the resale is rock solid.
What changed by year
- 1999 to 2005
- Steel frame bikes. Still good and very cheap, but the aluminium frame from 2005 onwards is where the value is for most buyers.
- 2005 to 2021
- Aluminium frame from 2005, KYB SSS fork from 2006, and after that mostly graphics and small changes for fifteen years. Any of these is a good buy if the engine has been looked after.
- 2022 onwards
- New bodywork, larger brakes, updated suspension settings and a slimmer feel. Same proven engine. The current bike.
Servicing a YZ250
Two stroke servicing is simple and the YZ250 makes it simpler. Premix at 32:1 to 40:1 with a good full synthetic two stroke oil, and change the gearbox oil every 5 to 10 hours. It only takes about 750 ml. Clean the air filter every ride and keep the power valve clean, because a gummed up power valve is the most common reason a YZ250 feels flat.
Top ends are the running cost. A race bike wants rings around 25 hours and a piston around 50; a trail or play bike can go longer. Check the reed petals when you do the top end. Keep an eye on the radiator hoses and the coolant level, and grease the linkage and swingarm every few months.
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 |
| Transmission oil | 15h |
| Piston & rings | 40h |
| Coolant flush | 60h |
Parts that fit a YZ250
Motul 800 2T 4L$179.90 · members $152.92
JT Alloy Racelite 49T Sprocket - Blue$74.95 · members $63.71
Vee Rubber Super H/D 4mm Tube 100/90-19$39.95 · members $33.96
DRC Rim Lock Alloy/Rubber 2.15"$28.95 · members $24.61
NGK BR8EG Spark Plug$24.50 · members $20.82
Zeta Z-Wheel Brake Hose Rear Blue Yamaha$99.95 · members $84.96
Motul Transoil Expert 10W40 4L$99.99 · members $84.99
Super HD 4mm 80/100-21 Tube$44.95 · members $38.21
JT Alloy Racelite 51T Sprocket - Blue$69.00 · members $58.65
JT Alloy Racelite 51T Sprocket - Black$79.95 · members $67.96
Tube 110/90-19 Super HD4mm$44.90 · members $38.16
SPP Alloy Fork Support Adj$34.95 · members $29.71
Buying a used Yamaha YZ250
With a bike this old and this common, buy on condition and service history, not year. Pull the plug and check the piston with a torch if the seller will let you, or at least do a compression test. Look for a clean airbox, straight radiators and a chain and sprockets that match the claimed hours. Check the frame around the footpeg mounts and the swingarm pivot for cracks on a bike that has done a lot of racing.
Prices go from a couple of thousand for an older steel framer up to near new money for a 2022 onwards. See the recent sold prices on the Marketplace page below.
Used Yamaha YZ250s for sale
4 listed on the MWMX Marketplace right now.
Yamaha YZ250 known issues
Power valve build up
Carbon builds up on the power valve and it sticks. The bike goes flat on top. It is a clean, not a repair.
Jetting
A carburettor bike needs its jetting right for the season and altitude. If it loads up or pings, ask what jets are in it.
Cracked pipes
The expansion chamber sits low and gets hit. Check it for dents and weld repairs, which change how the bike runs.
Yamaha YZ250 questions
- What premix ratio does a YZ250 use?
- Yamaha says 30:1. Most riders run 32:1 to 40:1 with a good full synthetic two stroke oil.
- How often does a YZ250 need a top end?
- Rings around every 25 hours and a piston around 50 for a race bike. A trail bike can go longer, but do a compression test to know.
- Is the YZ250 still made?
- Yes. Yamaha still builds it and the 2022 onwards bike got new bodywork, brakes and suspension settings.
- YZ250 or YZ250F?
- The two stroke is lighter, cheaper to rebuild and more fun for most riders. The four stroke is easier to ride fast on a slick track and is what most club racers choose.