Will I hear deceleration pop with a Power Commander and map installed?

Question: I'm planning to install your Alien Head exhaust on my Hayabusa along with a Power Commander using your pre-installed street map. The bike is completely stock with under 2,000 miles. Will I experience decel pop or backfiring with this setup?

Answer: Some deceleration pop is normal on any motorcycle, but we include a PAIR block-off cap with your system to greatly reduce this effect. With the PAIR system blocked and the correct map installed, you should hear very little, if any, decel pop.

For more insight, here’s how the PAIR system affects deceleration popping:

Why block the PAIR system, and does it affect the tune?

The PAIR (Pulsed Air Injection Reed) system injects fresh air into the exhaust ports to help burn unburned fuel—mainly for emissions purposes. On stock bikes, this helps the catalytic converter work more efficiently by increasing exhaust temperatures.

However, when you install an aftermarket exhaust that doesn't use a catalytic converter (like the Alien Head), the PAIR system can cause:

• Excessive decel popping
• Discoloration of the exhaust
• Premature failure of exhaust packing due to excess heat

Blocking or removing the PAIR system eliminates these problems and does not affect engine performance or fuel mapping, since the PAIR operates after the exhaust gases have exited the engine.

Note: Removing emissions components like the PAIR system may make your motorcycle illegal for street use. Always check your local and state laws before modification.