The 4-stroke is the most widely used dirt bike in professional racing. It's the engine that propelled Ricky Carmichael to iconic status, helped Ryan Villopoto create his own dynasty and today develops and ushers in a slew of amateur talent to the pro ranks.
The 4-stroke bike is the fastest on the market and unlike its 2-stroke counterpart eliminates the need to mix fuel and oil together. The competition between the 4-stroke folks and the 2-stroke folks borders on a strong rivalry as each side offers reasonable arguments to which bike rides best. We're not here to take sides! Different strokes for different folks as they say.
If you're looking to upgrade or replace the exhaust system on your 4-stroke you've come to the right place. As you'll see the number of available 4-stroke exhaust system is vast when compared to 2-stroke systems. The difference is the focus on increasing power or performance is less a variable than weight management and cost.
It's pretty easy to identify a 4-stroke exhaust design from a 2-stroke exhaust design. The 2-stroke exhaust system uses an expansion chamber - the prominent bulge in the exhaust pipe - to increase the engine's horsepower. You'll notice the 4 stroke exhausts do not have this as they rely on the exhaust valves opening and closing to control the exhaust pulses as they enter the exhaust system.
Four-stroke cycle used in gasoline/petrol engines. 1 - Intake, 2 - Compression, 3 - Power, 4 - Exhaust. Source: Wikipedia
If you desire to replace or upgrade an existing 4-stroke exhaust pipe, we wrote this guide for you. Some tips on how to pick the best 4-stroke exhaust system for your dirt bike (or ATV).
Complete 4-Stroke Exhaust Pipes
If you want a boost in power and performance in your 4-stroke engine look into a complete overhaul of your exhaust system from the cylinder head through the muffler. Much of the performance gain comes from the significant loss of weight of your bike, depending on the material used to construct the exhaust system. The common components used to construct 4-stroke exhaust systems include:
- Aluminum muffler with stainless steel header and mid pipe
- Titanium muffler with titanium header and mid pipe
- Carbon fiber can with titanium header and mid pipe
Motocross/Supercross Full Exhaust Systems
Exhaust systems for the track tend weight lighter than stock giving racers more edge in a sport where every ounce counts. The lighter materials like carbon fiber add expense and stand-up to the grueling and intense hard track riding. However, they dent and damage easier compared to heavier weight materials. Check out the deep throaty sounds and lightweight features of the Pro Circuit T-4 GP Complete Exhaust and the Yoshimura RS-4.
Off-Road Full Exhaust Systems
Off-road exhaust systems bring durability to weather rocks, logs and whatever the trails can throw at your bike. Stainless steel and aluminum compose most construction materials entwined with lighter materials like titanium. You can';t go wrong with anything from FMF but we recommend either the FMF Powercore 4 Slip on with FMF Powerbomb Header or the FMF Factory 4.1 with Powerbomb Header.
If you want to go the slip-on route which often offers similar power gains without the total overhaul and price tag check these durable stainless versions out: FMF Powercore 4 Slip-On or the Yoshimura RS-4 Comp Series
Off-road slip-ons are constructed with stronger materials like the full exhaust versions in order to increase durability and longevity on the trails. These two will keep you riding trails for years to come:Big Gun Eco System or FMF Factory 4.1 Titanium RCT - Carbon Fiber.
4-Stroke Spark Arrestors
Most aftermarket 4-stroke slip-ons already contain spark arrestors or are customizable to run with a spark arrestor. If you are happy with your stock muffler or upgrading is not an option and you require a spark arrestor then we'd suggest the following spark arrestors: Fastway Spark Arrestor End Cap or the ultra quiet FMF Q4 Spark Arrestor.