What Is The Most Reliable 250F Dirt Bike?

Not sure what the most reliable 250F dirt bike is? It’s a very common question asked by new riders or people that have never owned a 250 four-stroke motocross bike.

First of all, it depends on what year the dirt bike you are looking at is, the 250F’s rapidly changed from the first years until now, and some of them had problems that needed to be solved.

Although the manufacturer’s had problems with their high-performance quarter-liter four-strokes, Yamaha pretty much had it figured out from the beginning. They were the first to come out with a 250cc 4-stroke motocross bike (YZ250F) in 2001, which is 3 years before any other manufacturer’s got on the band-wagon.

What Is The Most Reliable 250F Dirt Bike What Is The Most Reliable 250F Dirt Bike?
250F Motocross Bikes

2001-2010 Years

Yamaha’s YZ250F became an instant success once riders started winning on them. In 2001 and 2002 the bike came with manual-decompression, making it a task to start the bike at times. 

But the only real problem the bike has ever had was in ’01 with a weak crankshaft that would go out on some bikes. In 2003 the Yamaha 250F came automatic-decompression. 

Up until 2006 the bike had no problems. The ’06 YZF did have a valve problem, but Yamaha recalled every one of them that was sent in. 

Riders that have had or been around 250F’s know that Yamaha was always the most reliable in the early years, even if it wasn’t the most powerful.

The Other Japanese 250F’s

2004-2006 were embarrassing years for the other manufacturer’s. Kawazuki’s KXF/RMZ250 was a nightmare on wheels, especially when not properly maintained. 

Honda’s CRF250R often ate valves like Americans eat McDonald’s grease burger’s. By ’07 the companies (excluding Yamaha) started figuring out the kinks in their 250F’s….

2011 and Newer 250F

If you are looking to get a 2011 or newer 250F and are deciding based on reliability, just pick a color. Really, pretty much all 250F’s now are reliable IF, AND ONLY IF, you take care of them.

Doing regular maintenance on a 250 four-stroke is very crucial and will make them last much longer. There’s no reason why you shouldn’t be able to get 50+ hours on a stock top-end, as long as you aren’t a Pro or riding it on the rev limiter all day long.

Which Brand Is Best Then?

Yamaha is still extremely reliable, but KTM and Honda are right up there as well. They’ve all developed high performance engines but have tweaked them to be reliable for many hours. 

Suzuki and Kawasaki are great options. Just because I don’t put them at the top doesn’t mean they’re bad by any means. It’s just that Yamaha, KTM (and Husqvarna) and Honda have progressed a lot in the past 10 years. 

Making Your 250 4-Stroke As Reliable As Possible

As I mentioned earlier, maintenance is the key to making your 4 stroke dirt bike last as long as possible. Of course, how you ride it plays a large role as well, but if the engine isn’t being maintained, it’s probably not going to last more than 20-30 hours or so. 

Maintenance means changing your oil every 5-10 hours or so (oil filter every other oil change), and cleaning your air filter every 1-2 rides.

Believe it or not, cleaning your bike will make it last longer, as well as lubing and cleaning your chain every ride, and re-greasing the bearings 1-2 times a year.

How Often Should I Check Valves?

There are a few more things you should do, but just doing these simple things will allow you to ride your 250F much, much longer.

It is extremely important to keep the valve-train in good running order. To be sure of this, the valve clearances should be checked at least once a year (every 20-40 hours of ride time to be safe if you’re racing). 

Contrary to what most people think, the cam/timing chain should be replaced with a new one every year.

If the chain breaks or seizes, the valves also seize and will be hit by the piston, causing massive damage to the engine. Buying a new timing chain is cheap insurance, so keep that in mind.

Or If You’re Lazy

But if you’re lazy and forget like me sometimes, a different strategy can be taken. 

Simply listen and pay attention to what your dirt bike is telling you. Is it getting harder to start? The carb may be dirty, but the valves may need to be adjusted. 

Hear a tapping or clicking noise? It might be the cam timing chain

Taking notice of these little things just might save you a large repair bill and a blown up 4 stroke. 

How To Find A Reliable 4 Stroke Dirt Bike

Other than doing the normal maintenance, choosing a reliable 4 stroke dirt bike mostly depends on its history. If you’re buying a new 250F then it’s no big deal, but buying a nice used one can be difficult to find. 

The best used 250 4 stroke to buy is one that is clean, has low hours, has been properly maintained, and the owner isn’t trying to hide anything.

For tips on how to find a good used dirt bike without getting screwed over, click here.

Kelley Fager

I help new riders learn how to safely ride and understand how to tune and fix their dirt bike in their garage.

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3 Responses

  1. cookie says:

    hi there just wondering does any one no what year did the 4s kxf20 come out i have one not to sure ov the year please 🙂

  2. cookie says:

    50 lol

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