Exhaust Backfire

The nature of the beast.

The BoosterPlug is designed to cure the usual lean running problems that haunts all modern fuel injected motorcycles.

The primary lean running issues are weak idle and low speed running where the bike easily stalls on takeoff, and a horrible on/off like throttle action that makes the bike hard to handle in city traffic and in tight corners/roundabouts/hairpins, etc.

The engine backfire on deceleration is also caused by the too lean air/fuel ratio - A lot of people think that the backfire/popping in the exhaust is caused by too rich mixture, but it's actually the other way round.

It is an annoying, but only a (sound) cosmetic problem, and if you look at the claims on our website you will see that we promise reduced exhaust puffing/popping/backfires - not to remove it entirely.

As you probably know, the BoosterPlug is only active in open loop mode, but sits idle in closed loop (If not check out the "how it works" for a full explanation on open loop and closed loop operation)

The problem about removing engine backfire is that engine braking is often a mix of open loop and closed loop conditions, so the BoosterPlug can not always cure this entirely.

If you snap the throttle fully closed, engine RPM will lower faster, and the constant RPM change will keep the Fuel Injection ECU in open loop - and the BoosterPlug will be able to provide it's fuel enrichment to remove the backfire.
But if you just ease off the throttle slightly, the RPM will sink slower, allowing the FI-ECU to return to closed loop operation, where the BoosterPlug is inactive.

So the backfire reduction depends to a certain degree on your riding style, and this is also why some owners experience that all backfire is removed with the BoosterPlug, where other still have some backfire left.