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Question answered 1 year ago
Answer: Whether for a sport bike, dirt bike, cruiser, or ATV, an after-market exhaust system or a slip-on muffler will improve the performance of your motorcycle, which is particularly important for the race track and competition.
The stock exhaust systems are designed to meet the emissions and noise-level restrictions set in place by most federal, state, and local authorities, and laws vary from state to state. It’s important that everyone check with local laws to understand what changes to your stock exhaust system are permitted.
Most after-market exhaust parts are lighter weight than the originals from the manufacturers. Most after-market exhaust parts allow the exhaust to flow more freely, and with reduced back pressure, and thereby improve performance. Performance improvements might be achieved with higher horse power and top end speed, or tuned for better low-end torque and quicker acceleration.
Allowing the exhaust to flow with less restriction usually demands adjusting and retuning of the fuel/air system, whether it is carbureted or fuel injected. In many cases, you might not know whether or not adjustment or retuning is needed until after you installed the new exhaust and taken it out for test-ride.
Some carburetors allow you to adjust the fuel/air ratio and the idle, but in some cases, changing the exhaust might require rejetting. Check out the simple guide to rejetting your carburetors: http://www.motosport.com/blog/a-simple-guide-to-jetting-your-carb
Fuel injection systems are usually electronically controlled. Adjusting and tuning fuel injection systems usually require a fuel management system. http://www.motosport.com/blog/sportbike-and-motorcycle-fuel-management-guide