If you're looking to reduce the excessive noise produced by the aftermarket M4 exhaust on your Yamaha FZ-07, there are a few options you can consider. Keep in mind that modifying the exhaust system may affect the performance and sound of the bike, so it's important to choose a method that suits your preferences while ensuring the bike remains within legal noise limits in your jurisdiction. Here are a few suggestions:
Silencer or DB Killer: Some aftermarket exhaust systems, including M4, offer optional silencers or DB killers that can help reduce the noise output. These are usually removable inserts that you can install in the exhaust to muffle the sound. Check with the manufacturer if they offer such accessories for your specific exhaust model.
Baffle Insert: If a silencer or DB killer isn't available for your specific exhaust, you could explore the possibility of installing a baffle insert. This involves adding a secondary baffle to the exhaust to help reduce noise. You may need to consult with a motorcycle mechanic or an exhaust specialist to determine if this is feasible for your exhaust setup.
Exhaust Wrap: Another option is to wrap the exhaust headers with a heat-resistant exhaust wrap. While this won't directly reduce the noise, it can help absorb some of the high-frequency sounds and potentially reduce the overall noise level.
Replace the Exhaust: If you find that the noise reduction methods above are insufficient or if you're not satisfied with the current setup, you may consider replacing the aftermarket exhaust with a quieter alternative. Look for exhaust systems specifically designed to offer a more subdued sound while still providing performance enhancements.
It's worth noting that local regulations and noise restrictions vary, so make sure to check the applicable laws in your area regarding motorcycle exhaust noise limits to ensure compliance. Additionally, consulting with an experienced motorcycle mechanic or an exhaust specialist would be beneficial, as they can provide you with personalized recommendations based on your specific situation.