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How Fast Does a 70cc Dirt Bike Go? All You Need to Know

In these extreme conditions, getting the best gears cannot be overemphasized to increase the odds of winning. The 70cc bike is a typical pick among the bikes, but how fast do they go? Stay tuned, as we will be sorting that in this article. How Fast Does a 70cc Dirt Bike Go?

A 70cc dirt bike typically has a top speed of around 35-45mph. However, this can vary depending on the make and model of the bike (which can make the bike ride as fast as going 50 miles per hour), the terrain it is being ridden on, and, most importantly, the rider’s technique.

It’s relatively easy to control the speed of your dirt bike when it’s set to 70cc. This skill becomes very important at high speeds because you don’t have much time to make decisions or act on them.

Engine Type Wise Average Speed of Dirt Bikes:

Engine Class (cc)

Multiplier

Speed (Kph)

50

0.8

81

100

0.9

89

150

1.0

97

200

1.1

105

250

1.2

113

300

1.3

121

350

1.4

129

400

1.5

137

450

1.6

145

500

1.7

153

550

1.8

161

600

1.9

169

650

2.0

177

700

2.1

185

750

2.2

193

800

2.3

201

850

2.4

209

900

2.5

217

950

2.6

225

1000

2.7

233

Technical Factors Affecting the Speed of a 70cc Dirt Bike:

  • Combustion Stroke
  • Air filter
  • Carburetor

Combustion Stroke:

All 4-strokes engines have essential components: the connecting rod, crankshaft, and piston.

As the piston travels up and down the cylinder, this lateral motion is rotated at the crankshaft. The longer the stroke of the piston, the larger the displacement of gas and air occurs in the cylinder. So to propel the piston, there’s a need to ignite a tiny bit of gas and air. This, in turn, creates expansion inside the cylinder.

The Fuel Delivery system includes the intake manifold, fuel injector, a spark plug, and intake/exhaust valves, which carry out different assignments.

Engines are called 4-stroke because four up and down motions are needed to complete the cycle. In the first stroke, the piston travels downward as the intake valve opens in a mixture of air from the atmosphere, and a metered amount of gas from the electronic fuel injector enters the cylinder. This is called the intake stroke.

On the second stroke, the piston travels upward, compressing the air and fuel to make a highly explosive mixture. This is called the compression stroke. At this point, the spark plug fires, sending the piston downward from the expansion of the air and gas mixture. This is called the combustion stroke.

As the piston travels upward, the exhaust valve opens to release the burned air-fuel mixture in the exhaust stroke. When the piston reaches the top of this stroke, the intake valve opens, and the cycle begins again.

It takes one up-and-down motion or two piston strokes to create one revolution of the crankshaft. Therefore, RPM is how many times the crankshaft rotates within that minute.

At wide-open throttle, the crankshaft may turn at 5000rpms or 83 times per second! Huge!

Whereas the piston traveled up and down 166 times in the same time.

So with this, a 4-stroke engine will perform more than a 2-stroke.

Air Filter

Advancements in technology from the carburetor to TPI machines, the air filter is tipped NOT to have huge effects on how your bike engine performs when it comes to TPI. This is because, on the carbureted bikes, it tells faster that your air filter is dirty compared to the TPI models.

How Fast Does A 70CC Dirt Bike Go

Also, a dirty air filter on its own reduces an engine’s power to the point that it tries to kill it in the long run. In the same vein, this party of people tries to run their engines without an air filter.

With this, the engine starts fine, but when it reaches a particular speed (typically at 15mph), the bike will not be able to run faster than this speed. In this situation, the engine will try to force itself to go more quickly, which is unsuitable for your engine.

But with a new air filter, the engine performs as expected, and the engine fires well.

The Carburetor:

The carburetor is used to mix gasoline into the intake airflow with ideal volume and proper timing. It utilizes pressure when air flows; the air pressure is lower than the atmospheric pressure.

This is Bernoulli's principle, which states that the faster air flows, the lower the air pressure; due to this pressure drop, fuel can be sucked into the air stream, but to bet faster airflow, venturi is needed to be added to the middle of the air hose; a section of air hose with a smaller diameter, and its function is to accelerate the airflow.

So, according to Bernoulli’s law, air can even be smaller. This makes fuel more efficient and easily sucked into the air stream. The carburetor uses Bernoulli’s principle to mix gasoline into the air stream towards the intake manifold.

How Carburetors Control Engines’ RPM:

In a variable venturi carburetor, the RPM is controlled by the adjustment of the width of the venturi.

Essential parts of the carburetor that are concerned with the RPM of engines include the piston and the needle jet.

The piston helps regulate the venturi’s width; it distributes fuel into the venturi’s idle air channel, an additional channel to flow the air at idle RPM. In addition, it functions to distribute fuel to the idle air channel.

The needle jet in its department is a pointed needle that adjusts the width of the main jet according to the piston position.

So, when the engine is idle, the piston is in the lowest position and makes the venturi very narrow, and the main jet is also covered by the needle jet.

How Fast Does A 70CC Dirt Bike Go

This condition forces air to flow through the idle air channel and fuel through the pilot jet. So, when we pull the RPM handle, the piston is lifted, which makes the venturi wider, and the main jet is opened so that greater air volume flow through the venturi and fuel is also sucked through the main jet.

How Fast Does A 70CC Dirt Bike Go

The higher the piston position, the wider the venturi will be; also, the wider the venturi, the greater the airflow, and the greater the airflow, the faster the engine RPM.

The Various Factors that Influence How Fast a Dirt Bike Can Go:

In a more general sense, many factors influence how fast a dirt bike can go. The most crucial factor is the rider’s skill level. A skilled rider will go much faster than a beginner.

The other significant factors include the type of bike (as a motocross bike is going to be faster than a trail bike. A 250cc bike is going to be faster than a 125cc bike). Also, the terrain, the rider’s weight, and the weather conditions all significantly affect how fast a bike rides.

How Fast Does a 150cc Dirt Bike Go?

Training To Better Your Riding:

As it is known that all racing is about crossing the finish line first, but when it comes to dirt biking, to achieve that, some factors dictate how fast you can go on your dirt bike. The major factors are technique, terrain, and competition.

Technique:

To navigate the rough patterns encountered in dirt biking, it is imperative to have a solid technical foundation. But the key to mastering the correct technique is REPETITION.

Regular practice braced with instructions from a coach is a way through which you can master the right way of doing a dirt bike right. And to be a master at work, a minimum of 15-20 hours of practice is needed, i.e., you have to use these hours for every aspect, be it the footwork, hip work, head work, arm work, etc., to be a worthy dirt biker that can perform at a considerate level. 

After mastering all these as singletons, you would still need to learn them in combination and spend hours molding them all as a single entity to be a true master.

Furthering on technique, when you feel like you have harnessed all the hard work put in the training grounds, ensure you hit the track, but ensure the trail is not a testing one.

Practice on a track that does not challenge you, so you want a flat field or somewhere where there are not many things to run into or different obstacles.

You’d like that to be as easy as possible as you want to try ground-up thinking about your footwork, where your knee is, where your arms are, and how you are moving around.

Another thing to do is ensure you film your riding while practicing and compare your videos to the pros to confirm if you are doing it right.

If you are riding and getting these flip-flops, you must have gone terrain before technique.

Terrain:

When you are done mastering your techniques, then challenge yourself with rugged terrains, challenge yourself with deep ruts, and challenge yourself with big bumps. If you make the technique suitable, all these can be tackled quickly.

Combining poor technique with speed can be very dangerous, and you can have your body bruised like a grilled chicken.

However, it is crucial to also practice regularly on the trying terrains as this will help you get on the bigger ruts. In addition, getting your body in the right place, the upper body, the legs, the arms, executing the throttle at the right time, etc., will better your skill set in the long run.

Competition:

When you are confident you have mastered the proper technique and roughed the rugged terrains well enough, it’s time to drop the gates, as you would want to know your habits on the actual road.

This is because when the gates are dropped, your mind turns off generally, as you would forget those techniques you have mastered and goes immediately into how to battle the competition, what place you are, and even most significantly, how to stay ALIVE.

But if you want to know if you have put in enough repetition and have mastered that technique set, then you have to observe if you can think about executing the techniques you have honed backstage when on the track without actually fretting over the little things.

This is how to ascertain that you are comfortable on the bike and see if what you have been putting in place for hours needs remolding, like whether The Mjolnir was in Thor Ragnarok or not.

How Can I Make my 70cc Dirt Bike Faster?

In this section, I will be talking about the 5 easy mods to help your bike go faster and let you move up the rankings in your races.

1. Air Filters:

How Fast Does A 70CC Dirt Bike Go
One of the crucial things to ensure is to get your air filter clean, or better still, get a new one when you get that old pit bike from a retailer or anywhere, as you would want your air filter to breathe in plenty of air without hassles in its way. 

DO NOT REPLACE YOUR AIR FILTER WITH A USED ONE; only replace it with a new one straight from the store.

2. Tires:

If you mean getting yourself and your bike up the standings above the regular rank, you do finish your races, and then you would need to have quality tires. Excellent big ballooned-out chunky knobby tires.

Steer clear of those cheap skinny Chinese tires if you want your bike to ride faster.

3. Throttle:

You should get your throttle well-adjusted and ensure it has plenty of spring to make it wind all back and not get stuck in between. Jammed or tight throttle will disallow you to have your bike fulfill its speed potential.

The best way to do this is to pull it apart and clean it. Then, while you are at that, spray the cable with a bit of wd-40 down to the air filter and take the air filter off and have a look at the end of the line; and when you are looking at the end of the cable, give it a route by springing it back and make sure that the slide goes all the way up and down and see to it that it moves nice and freely.

4. Show your bike a bit of love:

Don’t be an over-user. Treating your bike like a dog you’ve chased outside will only make it rusty. Rusty hands, loose bolts, and screws playing in the bearings (front and rear) will only make your bike perform like the big old unfit Thor that has lost his purpose.

The point is that you should ensure that you treat your bike well. You should clean it up and shine it up. Give it a good clean regularly. Keep it nice and shiny.

Also, you should regularly check the oil, change the air filter, and so on. Check your chain and ensure it is tightened well and is not loose. Also, check the tires and ensure all tires’ air pressure is okay.

5. Usage of New Sprocket:

Also, getting a new sprocket will make your bike run considerably faster. Try it out, too, if you want a significant boost in your bike's acceleration.

The Coolster 70CC Bike: The Pros and Cons:

The bike has a metal tank, and this makes it immune to cracks that can occur when the bike hits the ground during riding. But the major problem with metal gas tank is that it rusts over time – indeed, it does. So what else do you expect from a metal piece?

Also, much stress is not always needed when you want to get the bike started. Therefore, this is a nice feature that every bike should possess.

  1. The only exception, or should I say, the only scenario where this might not be true, is when you want to start the bike early in the morning (or in the cold).
  2. You have to use your hand to push the choke beneath the seat up, or just try messing with it by pushing it halfway or something. The goal is to have its position altered.
  3. Thirdly, the seat is comfy and gives you peace when you sit on it, although when you are riding and moving back and forth, it might start to hurt, as expected. But when you are just sitting on it, it gets pretty comfortable as you get used to it.
  4. Lastly, among the likable things about the Coolster 70cc is its suspension. The front and rear suspensions are excellent and okay as they can take those bounces when you take those little big jumps, or you take on those tree logs and bumps.
How Fast Does A 70CC Dirt Bike Go

One dark side of the Coolster 70cc is that its stickers are not well made, as a considerable amount of it gets scrapped off, starting as early as when it is being shipped.

Also, the carburetor. The carburetor bogs like crazy.

Other dislikable things are that its acceleration might be a bit below par, and also, the follow-come tires wear out fast and you might need to get yourself new tires faster than you might have imagined.

Top 5 Best Pit Bikes:

Model

Number of strokes

Top Speed (MPH)

Engine Type (CC)

Power (HP/RPM)

Suspension (Front/Rear)

X-Pro 125cc

4

60

125

7.75/7500

Xr70 replica forks with springs and oil damper/non-adjustable 9.5inch mono-shock

X-Pro Bolt 50cc

2

25

50

3.09/6078

Telescopic 27×590mm /12x270mm non-adjustable shock rear suspension

Coolster 70cc

4

30

70

5.4/8500

Non-inverted steel forks/mono-shock

Apollo DB-X18

4

55

125

Aug-00

Non-adjustable 750mm/ non0adjustable 320mm

XPRO 70cc

4

30

70

5.44/8500

Crf50 replica fork/8.5inch non-adjustable monoshock

The Honda CRF125F 125CC Bike Full Specs:

How Fast Does A 70CC Dirt Bike Go

If you are looking for a reliable pit bike to get your hands on, and you have been thinking about the Honda CRF125F 125CC, here are the details of the specs of the dirt bike:

  • Engine Type: Single cylinder, air-cooled, 4-stroke, fuel injected
  • Displacement: 124.99cc
  • Bore X Stroke: 52.4 x 57.9mm
  • Horsepower: 5.44HP/8500rpm
  • Transmission: Manual
  • Compression Ratio: 9.0:1
  • Ignition: Electric
  • Starting System: kick start, foot brake
  • Max Speed: 30+ MPH
  • Front Suspension: 31mm Telescopic Fork, 5.2 inches
  • Rear Suspension: Pro-Link single shock, 5.5 inches
  • Tires (Front/Rear): 70/100-17, 90/100-16
  • Tires for Big Wheels version (Front/Rear): 70/100-19, 90/100-16
  • Front Brake: 240mm hydraulic disc
  • Rear Brake: Drum
  • Curb Weight: 194 lbs
  • Ground Clearance: 8.3 inches
  • Seat Height: 29.1 inches
  • Base Price: $3,099
  • Big Wheels Price: $3,599

Various Dirt Bikes and Their Specs:

Bike Manufacturer

Number of strokes

Top Speed (MPH)

Engine Type (CC)

Ground Clearance (inches)

Seat Height (inches)

Honda CRF125F

4

45

125

8.3

29

KTM 65 SX

2

62

65

11

29.5

Apollo DB25

4

35-40

70

6

21.65

KTM 50 SX

2

45

50

10

27

Coolster QG50 49cc

2

30

50

6.5

24

Kuberg 2016 Freerider

-

34

48 Volt Motor

13

40

RPS Xmotos

4

50

70

12

30.5

Also Read:

How Fast Does a 125cc ATV Go?
How Fast Does 110cc ATV Go?

Frequently Asked Questions (FAQs):

How fast is a 450-dirt bike?

A 450 dirt bike rides quite fast as compared to others. The 450 bike rides as fast as 110-115mph. Quite fast, yeah!

How fast does a 70cc Apollo dirt bike go?

The 4-stroke bike’s top speed is around 35-39mph and operates with a maximum power of 5.5hp.

How fast is 2000cc in mph?

A 2000cc bike has an average top speed of 201.168 km/hr.

How fast can a 70cc mini bike go?

The maximum speed a 70cc bike can attain is 50mph, and it is only when you put a lot of effort into it and if you also use the right set of techniques.

What makes dirt bikes faster?

There are many things to make your bike faster such as replacing the sprocket, regular maintenance, etc.