Popping in the exhaust is a non-problem (it may be irritating, but it is not hurting anything) and has many possible causes: the most common cause is that the fuel to air mixture is too lean at idle. This could be caused by a change in air density, a change in fuel quality, a faulty air cut valve on the carb (if equipped with one) or having the idle speed set too low - idle is typically 1200 to 1500 RPM. Other causes include a vacuum leak between the engine and carb, leaking exhaust gasket, reduced exhaust back pressure caused by a deteriorated muffler or the installation of a low restriction exhaust.
Best way to reduce or eliminate popping in the exhaust is to increase the idle speed, try a different spark plug, if you recently changed from non-oxygenated fuel to oxygenated fuel, switch back. If you changed fuel brands or octanes, switch back. If you are using less than 93 octane fuel switch back to the higher octane. If you are operating at a lower altitude than previously then the air is more dense and the air/fuel ratio is leaner than previously. If you made any performance 'improvements' (remove the top from the air box or installed a K&N air filter then the carb needs to be adjusted to compensate for the reduced intake restriction.
Consider these options and perhaps try changing the idle speed or improving the sealing of the exhaust and/or intake systems.
Best way to reduce or eliminate popping in the exhaust is to increase the idle speed, try a different spark plug, if you recently changed from non-oxygenated fuel to oxygenated fuel, switch back. If you changed fuel brands or octanes, switch back. If you are using less than 93 octane fuel switch back to the higher octane. If you are operating at a lower altitude than previously then the air is more dense and the air/fuel ratio is leaner than previously. If you made any performance 'improvements' (remove the top from the air box or installed a K&N air filter then the carb needs to be adjusted to compensate for the reduced intake restriction.
Consider these options and perhaps try changing the idle speed or improving the sealing of the exhaust and/or intake systems.
