Loud exhausts might save lives on the street but on the track or trail most riders prefer the "silence is golden" treatment.
A loud exhaust can damage hearing, elicit a call from an annoyed neighbor and prevent you from competing in a sanctioned off-road racing event that requires exhausts to register at or below a certain decibel level. A deep throaty sound is the most preferred noise to emanate from a dirt bike's exhaust and makes for a fantastic impression but can still register a bit too loud. Sometimes a high-pitched racket spills out that needs addressing, or a lower-end or well-used exhaust systems no longer keeps a lid on the racket while some riders might just prefer a softer sound for personal reasons.
How To Quiet a Loud Exhaust
You have several options to consider, when making the exhaust on your dirt bike quieter, from simple maintenance to a full exhaust upgrade so let's cover the methods and you can decide what best suits your needs.
Replace Exhaust Packing
Dirty exhaust packing emits a sort of shrill, tin can pitch. If the noise doesn't bother you, the lack of horsepower will. Dirty packing can also push the decibels high enough to disqualify you from off-road events with sound restrictions. Replacing dirt bike exhaust packing offers the cheapest and easiest of the solutions to make the exhaust quieter on your dirt bike but don't expect a steep drop in the noise level.
Read How To Repack Exhaust On a Dirt Bike or ATV for more information.
Add a Spark Arrestor
A spark arrestor replaces the muffler on your 4-stroke or silencer on your 2-stroke. This requires some mechanical ability to remove and replace the existing pipe. Thankfully, you don't need to replace the entire exhaust system but you will still spend a few hundred bucks for a spark arrestor along with the time involved for the exchange or additional cost to hire a professional. Most trail bikes already come with a spark arrestor so keep that in mind when in the shopping phase, but if you plan to ride your Motocross bike on the trails during the off-season or race off-road then you'll need to invest in a spark arrestor.
Alternatively, on 4-strokes you can convert your current muffler to a spark arrested muffler by adding a spark arrestor end cap, a cheaper alternative to a full muffler replacement. The end caps remain in place permanently but you can remove the spark arrestor screens when racing track.
Upgrade the Exhaust System
Stock exhaust systems often emit a high-pitched noise that annoys most riders – one reason why so many grab an aftermarket exhaust soon after purchasing the bike. Aftermarket exhausts also offer more horsepower and weigh less than stock, both attributes racers find as easy reasons to justify the expense. An aftermarket exhaust likely won't get you under the decibel requirements for off-road racing but you will find the sound far more palatable than the whine of stock.
Read Should I Upgrade the Exhaust On My Dirt Bike? for more information and keep in mind all the other necessary changes after replacing the stock exhaust system.
Electric dirt bikes have arrived and while purists have tried their best to prevent the plug-and-ride bikes from hitting the tracks or trails more and more manufacturers have embraced the future. Electric dirt bikes produce no engine noise and you can theoretically ride them in your urban back yard with neighbors on both sides and behind you, and they'd never be the wiser.
Most riders opt for a quieter exhaust system when required for trail riding or other off-road events that have noise restrictions or target the aftermarket systems for the power gains. A quality set of ear plugs helps with personal noise tolerance levels but if your exhaust system sounds intolerable one week compared to the last time you went for a ride look into the exhaust packing, you might find some relief there.