There have been many theories out there to explain what a power band is; however, there is a lot of information out there that furthers many misconceptions. This article clarifies what a dirt bike power band is and dirt bike power band uses on a 2-stroke and a 4-stroke dirt bike.
What is a Dirt Bike Power Band?
Put and in generic terms, a power band of an engine in the range of operating speeds under which the machine or the motor can operate most efficiently. Some 4-stroke dirt bikes have relatively broader power bands, and some bikes can go up to the speed of 14000 RPM, and this can be done by using connecting rods and pistons to reduce inertia and stress on the parts.
There are a lot of questions on whether one should stay in the power band range or not. The safest answer to this question is: YES. It is advisable to stay in the range because it is within this range that you will produce the bike’s peak performance. Seasoned riders would know the benefit of this and will mostly stay within the range.
The range varies from bike to bike and even more so, within 2-stroke bikes and 4-stroke bikes. If you are a seasoned rider, you would know the tricks of the trade, i.e., using the clutch to power up the RPM on a turn without producing extra power to the wheels. This comes with experience and with an understanding of the powerband for each gear.
There is a difference between the 4-stroke and the 2-stroke power bands. All engines have a power band, but not all power bands are noticeable in the same way for all the bikes. As mentioned before, four-stroke bikes have a broader range of power, and it will remain more or less consistent until it reaches a higher RPM, where it will most likely become stable. Four-stroke bikes will have a lot of power on the lower end, maximum on the mid-range, and then will start reducing towards the top-end.
On the other hand, most 2-stoke bikes will have maximum power in the upper mid-range and towards the topmost end.
Dirt Bike Power Band – A deeper understanding
A long time ago, 2-stroke engines had very limited power bands. You could expect a 2-stroke powerband engine to produce no more power than the low-to-mid RPM’s. There were very select ranges- some 2-stroke engines would produce maximum power at low-to-mid RPM’s and others would produce power at the topmost. There was almost no balance that one could find in most 2-stroke bikes.
With the emergence of the powerband for 2-stoke engines, mostly mechanical and electrical, the engine’s speed is designed to control the range of the power bands. Let us look briefly at how this happens.
The power valve has a very important role to play in moderating the position of the power band. The power valve works in such a way that it regulates the size of the exhaust port. This has a direct impact on the position of the power band. If the size of the exhaust port is smaller, then there is going to less space for airflow. If that were to happen, then the power potential of the engine would be less. When the exhaust is more open, then there are more chances for air to flow, which in turn gives more power to the engine.
There are huge advantages to having power valves on your bike. As mentioned above, it can allow for your bike to produce a lot more power than usual through a broad RPM range. These valves are also adjustable, which means that you can manually adjust them according to the RPM range that you have set.
It is important to note that engines can also be tuned in for low-to-mid range. Such engines are going to have maximum power down low, a relatively chunky mid-range, and low power at the top. Supercross riders favour this kind of power because it is easy to navigate, you feel more in control as a rider and is also safer. If you are interested in tuning, you can tune your bike to any one of these ranges. There are very few riders out there who have tuned their bikes to the extremes. Professional riders on outdoor tracks almost always use engines that are all high-RPM power.
These beasts are extremely fast and require highly skilled professionals to operate them to their full potential. On the other hand, Enduro riders that are used to slippery, technical conditions use bikes that are tuned for the lower-end. Trail riders use no other bike other than low-end.
The Best Way To Use The Power Band
The best way to use your dirt bike and the power band on it is by putting it in the appropriate REV range. This is when you will be in your power band. Let us elucidate this further through an example- Suppose you have a high RPM bike and consider that you didn’t make any power until you were at 8000 RPM, what you would want to do is drop down to the third gear and then accelerate. That is when you will be in your power band.
If you do accelerate let’s say at 4000 RPM while cruising on the highway and you push open your throttle, yes, you are going to accelerate, but there will be no immediacy to your acceleration. In other words, there is no point in accelerating and pushing open your throttle, if you are not in your power band.
A rider must choose their powerband according to the skill level, the terrain they usually ride on, and the general ‘hygiene’ factors. Let us look at some of how we can do that:
Knowing Your Skill Level
If you are a beginner rider, then low to mid-range power bands should do. Seasoned and professional riders, on the other hand, can benefit from top-end powerbands. If you are used to riding on a terrain where there is less traction, and the terrain is more difficult to navigate, it is going to be more difficult for you to function with a top-end powerband. In this case, low-end power is going to help you keep the bike more in control and as a result of that, go faster.
Understandably, expert riders need more power to stay in the game, but this can be a problem for even less seasoned riders with better conditions and is definitely dangerous in slippery terrain.
Terrain obstacles are essential to consider, and good practice would be to check a wide variety of things such as soil content, elevation changes, and the frequency of jumps that you are going to encounter, on the track. For this kind of terrain, low to mid-range powerbands are going to work extremely well on mud and sand. If the track is compact and tight, it is going to favour lower-end powerbands because it can be difficult to navigate around corners with top-end power bands.
The best time to use a broader power band would be for trail riding over a relatively wider variety of terrain and soil conditions. Upper mid-range to top-end power bands work best over long and winding up hills and fast turns and corners.
Well, this is a no-brainer. Powerbands that are designed for lower and mid-range require less maintenance as compared to the ones designed for high RPM. High RPM engines usually require more use of the clutch to get the engine up to the REV range, where the power band is most efficient. An engine that is required to sustain high RPM is going to be less durable on a long-term basis and will require more frequent replacement of parts such as piston rings, clutch plates, reeds amongst others.
High-rpm powerbands have high-compression ratios, so it requires a more detailed inspection of the fuel selection. If you are a seasoned tuner, you know that the recommendation for this would-be racing fuel.
We hope that this was a comprehensive study and understanding of what power bands are. Having the right knowledge of the power band on your bike can be extremely beneficial and help you in understanding your bike better, hence making your use more efficient. There are many riders out there, who have spent years riding but because of not knowing about the power band, have not been able to use their bikes to their full potential.
You need to understand what kind of rider you are and how you would like to tune your bike according to the criteria mentioned above. Terrain plays an extremely important role in deciding whether you should get tuned for a low-end or a high-end and you must know your existing skill level, before making a choice. We hope that this makes the concept of power bands clearer and the best ways of using a powerband for your dirt bike.