popping/backfiring problem

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Phat_J · #1 Unread post by **Phat_J** » Fri Jul 07, 2006 6:20 pm

I recently installed exhaust, intake and jetted the carbs on my bike. Sometimes it will make a popping/backfiring sound. It only does this after I accelerate then let off of the gas and coast. If I am accelerating there is no problem, and if the clutch is in there is no problem. I am thinking the bike may be running a little too lean? Is this really a problem, or just a side effect of the new pipes having much less back pressure than stock?

Mintbread · #2 Unread post by **Mintbread** » Fri Jul 07, 2006 8:07 pm

Fitting a performance exhaust can make the bike run a little lean but it shouldn't be too bad if you rejetted (bigger of course). A little fine tunning regarding your settings should minimise the popping.

CORSCO · #3 Unread post by **CORSCO** » Sat Jul 08, 2006 6:37 am

Richen the mixture screws. Try 3 turns out. If you have an aftermarket filter, take it out and go back to stock. K&N filters cause more problems than they are worth.

Bachstrad37 · Mon Jul 10, 2006 10:57 pm

I believe your Custom is fuel inject?

Regardless, you're firing because the reed valves on your bike is feeding air into your exhaust system. These reed valves is part of your emission system. They open up upon deceleration so that any unspent fuel is sent back for burning. Stock systems do this very effeciently and cause little to no noise. Aftermarket exhaust which are much less restrictive could care less about dealing with this noise. You can do one of two things:

Find the reed valves and either restrict it by plugging it up somehow (I used 1/2 in marbles)

or

Remove these hoses altogether.

The first option is easy and quick. And if you plan on reselling your bike, it's the best option.

The second option is great for cleaning up your ride by pulling out all the hoses and vacuums that you will no longer need.

I don't know how your Custom is assembled, but the basic principle still applies. Your service manual will best describe where the various parts are. Me, I used Gadget's online referece from his webpage.

TechTMW · #5 Unread post by **TechTMW** » Tue Jul 11, 2006 4:49 am

CORSCO wrote: K&N filters cause more problems than they are worth.

Everyone thinks I'm crazy when I tell them this. "The Advertisements and all my friends can't be wrong!!"