I need more power!
Said just about everyone who has ever ridden a dirt bike or ATV in competition. And even those who just enjoy blazing along trails eventually want a faster bike without needing to buy a new one housing a bigger engine.
Little tricks here and there offer subtle gains in power and riders who make adjustments for increased performance can squeeze out extra speed simply because they ride better and thus faster. But after finessing all the tweaks and improving your riding skills, eventually the available power feels a bit stale and you look for ways to ratchet up how fast the bike actually goes.
Increasing the horsepower in a dirt bike or ATV comes down to just a handful of parts with two components generally getting replaced together therefore the cost involved might deter some riders especially if all suggestions get finished altogether. But once done, the power gains prove quite noticeable and all the prior fine-tuning, in many respects, gets reset allowing you to make additional adjustments later.
Allowing more air into the engine allows it to breath just like if you had the capability to physically inhale more air as you exercised you could get the oxygen needed to perform even faster. More air along with the equivalent in extra fuel to accommodate the extra oxygen equals more power.
Unfortunately, you can't upgrade or change the size of the airbox equipped on your dirt bike. You can make modifications to your current airbox like drilling holes and adding air box vents however you can "unleash the hounds" so to speak and free the air flow a much easier way. Accomplish this by removing the backfire screen but if you do that you also need to change the air filter. You can't remove the backfire screen, which prevents sparks from firing into the intake system, while still using a regular oil-soaked air filter.
Therefore, you need a flame-retardant air filter and use air filter oil with a higher flash point. A number of air filter kits address this which also include a lighter and stronger air filter holder that seals the air box better that stock preventing air from escaping.
But using this method to upgrade the intake system won't work very well unless you also...
Exhaust - Upgrade Complete System or Slip-on
Upgrade the exhaust. With all the extra air pouring in to the engine you need a way to expel it. Think of it like adding an extra lane of travel on a freeway without following through to the end. You allow more cars but eventually result in a traffic jam just further on down the road. Without upgrading the exhaust you can't rid the engine of all the extra air. Check out our aftermarket exhausts for 2-stroke and 4-strokes.
Upgrade the exhaust by changing the full system or adding a new slip-on. You can do either however don't just grab the coolest looking muffler because depending on your bike model, your riding needs and what you have done to the intake you might need a bigger overall system which means a lot more work and usually means more investment or you might get away with the slip-on.
If you want immediate results in a routine maintenance upgrade then invest in a big bore kit the next time you need a top end. Of all the options available, a big bore kit offers the most noticeable boost in power and depending on the make and model of your ride often the least expensive.
Camshaft and High Compression Piston (4-strokes)
If you own a 4 stroke you can skip the big bore and go with a high compression piston along with camshaft upgrades. This might require a mechanic but if you know your way around an engine pretty well you can probably do this yourself. For some insight, your average pro probably runs a high compression piston rather than a big bore kit.
These upgrades performed altogether or piecemeal should give you the power needed to challenge your skills and help raise the level of your riding. If you race, depending on the class, these improvements will not only help you compete at a higher level but likely level the playing field as most of the podium contenders probably have already made the change.