Take a Bite Out Of Decel Pop!

Your new stock Harley-Davidson sounds like a sewing machine and you need an exhaust system pronto! You purchase one from a reputable company such as West End Motorsports and you install them. Everything sounds great, until you let off on the gas. The deceleration popping sounds horrible! Here are some tips to help alleviate your aggravation and help take a "bite out of your decel pop!" 

But what is causing the decel pop to begin with? The pop is inherent in EFI (Electronic Fuel Injection) controlled engines. The popping sound you hear is actually unburnt fuel igniting in the exhaust pipe. The fact is, the pop has been there all along. The reason it wasn't audible until you installed an aftermarket exhaust is that the stock mufflers are very restricted and uber quiet. So by opening up the exhaust system with a less restrictive, performance exhaust, the popping sound becomes very audible. Not only are the stock mufflers sewing machine quiet, but they also restrict fresh air from entering the exhaust that aids in the combustion of that unburnt fuel. That process is due to reversion. 

So how do you negate the annoying pop, pop, pop?

Your choice of slip-on mufflers have a lot to do with how much pop you'll receive to your ears. Loud, wide open baffle designs will let you have all of the sound out of your engine and will definitely make the popping more inherent. Less aggressive mufflers will dampen the popping, limiting the annoying sound.

Ultimately, proper engine tuning will reduce much of the popping. If you have installed a Stage 1 exhaust and air cleaner upgrade and didn't tune your fuel injection, you are probably running too lean to begin with. Proper fuel injection tuning can all but eliminate the popping issue and is a task best completed by a trained tech who's good with dyno testing. 

Is the popping still there? Check is to see if you have an intake air leak. An intake air leak can be caused by a leaky intake manifold seal or old vacuum hoses. If they have been recently disturbed during recent performance upgrades, then you shoot troubleshoot that area.

If the intake is sealed properly, then the next thing to check is the the exhaust system for any leaks as well. Check around the heads to see any obvious exhaust soot on the pipe and check the rest of the system of any cracks.

Sometimes chasing down issues like this can be daunting, and the assistance from a qualified tech is necessary. Call your local motorcycle shop to go over the points discussed here. You too can take a bite out of your decel pop!