Rebuilding a Dirt Bike: How Often to Do It, Average Cost, and More


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Photo of man changing oil on 4 stroke dirt bike engine.

Having a dirt bike that can perform as well as possible on the trails, and be easy to maintain, both in cost and time is the dream of every dirt bike owner. This is a difficult balance to reach. Additionally, dirt bikes need to be rebuilt more than many other vehicles out there because, well, they take a lot of abuse. When it comes to rebuilding a dirt bike, there is a big difference between cost and frequency when we’re talking about 2 strokes and 4 strokes.

How much does it cost to rebuild a dirt bike? Rebuilding a two-stroke dirt bike ranges from $50 to $500 and four-strokes are $1,100 and up, depending on the specific components replaced by the shop.

Each type of dirt bike has pros and cons, but 2-strokes are quicker, easier to repair, and really light to haul around. Let’s take a look at the differences in each of these primary types of dirt bikes, what the overall maintenance looks like, and what both auto shops and real-world experience say when it comes to the dreaded rebuild.

How Often Should You Rebuild Your Dirt Bike?

Dirt bikes are pretty hardy machines that can withstand rough conditions for a long period of time. As such, it’s hard to make definitive limits on how often they should be rebuilt. However, the two main factors to consider are your RPMs (rotations per minute) and your riding style.

Many dirt bikes can last for over 100 hours of ride time between rebuilds if it’s casually ridden, but more aggressive riders on rougher terrain may find that their bike wears out within 20 hours or less. As a general rule, you shouldn’t ride for more than 100 hours without performing some level of maintenance.

If you ride your bike over rough terrain and push it aggressively up steep hills, you will need to maintain/rebuild it much more frequently than that.

In addition, there are some warning signs that will start to show up when your bike is in need of repairs. Some of the major signs include low compression (loss of power), difficulty starting, and plug fouling. Keep an eye on any handling problems as well, including steering difficulty and poor suspension.

How Long Does a Dirt Bike Take to Rebuild?

In terms of how long a rebuild takes… well that really depends on how severe the issue is and whether you take it into a shop or tackle the rebuild yourself. Experienced dirt bike owners who are mechanically inclined and have all necessary parts on hand, can complete a rebuild on their dirt bike in a single day. However, taking your dirt bike to a shop for a rebuild could take a few days or weeks.

If you take your bike into a shop, it may take a few days or even weeks to get it back, depending on how busy they are and if they need to order any parts to complete the job. If you feel confident in your own ability to rebuild it, it may be worth learning how to do it yourself.

If you need to custom order parts and wait for them to arrive, your bike could be out of commission for a week or two. In order to prevent lags like this, it’s handy to keep a set of spare parts at home at all times. That way you’ll be able to make repairs quickly and get back on the trail!

How Much Does It Cost to Rebuild a Dirt Bike?

Even the best bikes break down and need maintenance over time. If you are experienced, you could do these repairs at home. Otherwise, you’ll need help from a mechanic. Each part below is a rough estimate of what we would pay, but it will obviously vary depending on the dirt bike model and product quality. Some dirt bikes can only take specific parts, so specialty models will be more expensive than the average.

Dirt Bike Rebuild Cost Breakdown

PartCost
Gasket Kit$20 – $130 depending on the bike (average cost is around $30).
Cylinder Plating$250 but this cost is often included in rebuild/cylinder kits.
New Cylinder$250 – $550 is the typical range (the average price is on the lower end of this range).
Piston Kit$45 – $100 and usually includes piston, rings, wrist pin, circlips.
Labor$150 – $200 minimum.
TOTAL$715 to $1,945 (est)
All prices are estimations and will vary greatly depending on your specific bike and the specific parts you choose.

Dirt bikes can be pretty expensive to repair, so make sure you’re ready for these fees before you buy one. As a side note, remember that dirt bikes that are designed for children are generally easier to repair and their parts are less expensive. There’s no need to rush into a full-sized bike right away, especially since it can save you some money!

What to Know About 2-Stroke Engines

Gas-powered dirt bikes come in two main types: two-stroke and four-stroke engines. They are fairly different when it comes to maintenance. Two-stroke bikes aren’t made very common anymore because they aren’t very environmentally friendly, and there are increasing restrictions on them. But if you have a two-stroke bike, it’s important to understand how to take care of it and rebuild it if necessary.

Two-stroke engines work by using a combination of functions in a single-piston movement. The piston revolves around at a lower pace which, in turn, gives a better kick than the 4-stroke. Many experienced riders, prefer this extra “kick”.

During the upward movement of a piston, air, fuel, and oil mix inside the combustion chamber. This gives the 2-stroke a much quicker speed in which it outputs energy. This gives the dirt bike a quick start and enables the rider to race across dirt tracks at amazing speeds.

Because it only has two functions to go through, combustion and exhaustion, it makes the ride much smoother and it doesn’t take much effort or power to get the bike going. Check out the video below for a more complete comparison between these two engine types.

What to Know About 4-Stroke Engines

Normally, the two-stroke dirt bike is more reliable in the long term as this bike is great for beginner dirt bikers. Four-strokes don’t have as much power as two-strokes, but they run more smoothly and have fewer emissions. They also don’t wear out as often, so you won’t need to rebuild them as often as two-strokes.

There are four steps the dirt bike has to go through to work: intake, compression, combustion, and then exhaust. The more the pistons are pushed, the process becomes slower so the dirt bike isn’t able to perform quicker. Every rotation takes time and power, so this engine design does sacrifice a bit of that instantaneous “kick” you’ll see in a two-stroke.

Basically, two-stroke engines only need to move two revolutions to create their power, while four-stroke engines need to move four revolutions.

The name behind the four-stroke engine means the piston goes through four strokes/two crankshaft revolutions in order to complete the intake, compression, and both power/exhaust strokes. The piston moves from the top cylinder to the bottom to reduce pressure inside the cylinder.

When the compressed air, fuel, and oil mix, the combustion chamber underneath the piston makes a fresh mixture. During downward movement, the piston and the mixtures (air, oil, fuel) become compressed and flow into the combustion chamber. This then flushes the burnt gases downward and out of the opened piston/exhaust port.

Rebuilding a Dirt Bike Engine

Rebuilding a two-stroke or four-stroke engine doesn’t necessarily have to be done by professionals. However, the actual process can have some complications, especially if you have to locate hard-to-find parts. If you’re interested in doing it yourself, a basic breakdown of the rebuilding steps is available here.

For a very helpful visual breakdown of the process, you can also check out the video below.

Maintenance on Two-Strokes

What’s great about the two-stroke dirt bikes is that they have fewer problems, and those can generally be handled with quick and easy fixes. Parts can be purchased and are usually quite cheap. It’s much easier to work on the bike and be simple enough that any rider, no matter their experience can work on it, lowering the cost by significant amounts.

The maintenance on a two-stroke is definitely not as expensive or difficult compared to the four-stroke. However, the bike is known to wear down quicker and parts get easily beaten down. Thankfully it’s not expensive to replace but because of the size of the engine, while considering the dirt bike’s overall composition, the problems are easier to locate.

The two-stroke dirt bike is consistent in staying in good shape despite its tendency to wearing down more quickly. The amount of power it provides will make any new dirt bike motorist excited. A great bonus is that the lifespan of the two-stroke is about the same as the four-stroke, making this dirt bike a great overall choice.

Maintenance on Four-Strokes

While the four-strokes don’t have as many issues to maintain, they are more expensive to fix once they occur. But they are more environmentally friendly from the lack of the oil-fuel mixture that the two-stroke has.

When parts break down, the four-stroke becomes the most expensive configuration in dirt bikes to repair. The engine is even harder to fix because there are numerous parts and some areas aren’t as visible, unlike in the two-stroke. The great news is, they don’t break down often so the dirt bike’s maintenance evens out over its long lifespan.

TIP: If you want to learn more about which configuration is more reliable, along with some concrete differences between two-stroke and four-stroke dirt bikes in terms of power, engine size, maintenance, and reliability. See our article Dirt Bike Reliability: Is a 2 Stroke More Reliable Than a 4 Stroke?

Two-Stroke Rebuilds: Auto Shop vs. DIY

Two-stroke and four-stroke rebuilds are similar. in many ways, but the key difference is that two-strokes require fewer mechanical parts. This could make it cheaper overall, but you may need to go into your local shop more often than if you had a four-stroke bike. Typical maintenance procedures can range between $700-$800.

It is more common that someone would want to do the maintenance on two strokes themselves and only replace certain parts that are easy to manage. This is, of course, way cheaper and ranges from $15-$700. Be sure to check the dirt bike manual but many will say to replace certain pivotals, bottom cranks, cylinder fires, and to freshen the pistons.

Four-Stroke Rebuilds: Auto Shop vs. DIY

This has more torque power but requires more maintenance with more transitional oil. They mainly check the cylinders off old cylinders. An auto shop would also check to see if the boots are good and clean out any dirt so grease can flow better through the gears. It’s highly recommended that you don’t perform maintenance by yourself because it can go “way over your head.” 

If we were choosing to do maintenance at home the overall cost ranges from $800-$1,000, especially with new pistons. During the traditional overview, one needs to do swing arm linkages, A-arm bushings, wheel bearings, and brake pads similar to a two-stroke.

It’s important to stay on top of one’s checkups after every ride. Make sure there are no drip leaks, problems with the tires or brakes, and make sure the headlights are in good shape. There’s also the yearly oil change, fuel filters, and whatever needed maintenance.

The good news about off-roading bikes is that, unlike a street motorcycle, it doesn’t get used as much so the fuel, oil, and tires will more likely stay in good shape for a while. If someone takes their bike out less it’ll be cheaper to work on.

Which Bike Is Better in Terms of Rebuilds?

It honestly comes down to every person’s preference. Two-stroke engines are noisier and produce more exhaust fumes but have more power being lightweight making them a popular choice for racing. They’re also cheaper to maintain and easier to rebuild when necessary. They also might be harder to find since they aren’t made quite as often now.

Four-stroke engines are heavier and provide less power. However, they also tend to run more smoothly and give off fewer exhaust fumes. These bikes will last longer between repairs and could have a longer overall lifespan, however, they’re more complicated and expensive to rebuild.

More Useful Information

  • 2 Stroke vs 4 Stroke Dirt Bikes: 21 Pros and Cons You Should Know – Did I just make your decision harder while you’re trying to decide between the two main types of dirt bike? Well, if you are stuck in between, then you’re going to want to see this article on all the pro’s and con’s between these two bikes (this goes far beyond just maintenence an rebuild considerations).

John Hayes

A street biker turned dirt bike rider, I've been riding motorcycles since I was 12-years-old and have a passion for the technical aspects of dirt bike riding.

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