Question,
I just put on Vance Hines slip ons and the bike sounds great but now when I drive it and let go of the gas or start to stop its back fires, is this normal after you put on slip ons?

Thanks
Wolvie

 

Your bike is running lean. You need a rejet or remap. Don't know which since you don't list the year and model of your bike.

 

+1 You might for the love of your bike want to fix that soon.

 

Its a 08 1200L sportster, (EFI)

 

Hmmm , me was learned that pops out the carb = lean.

Pops out the pipe = rich.

Hmmm ...

 

Wolverine, You will need to remap. It's running lean.

 

If its lean, its thats amazing because I heard right here on this intranetz forums that pipes dont mess with the airflow enuff to cause a bike to run lean

** disclaimer** I am being a smartazz in reply to peeps who think pipes/baffles dont make a difference to a bikes tune

Seriously, Get your bike in tune before you run her hot very much...

 

agreed. i did a bunch of searches and found a ton of topics saying as long as i didnt change a/c it would be fine[sm=boosign.gif]............well i put pipes on and it was popping like crazy on decel. needless to say my PC is on the way. ive always been a believer that if its on the internet its gotta be true.........another one of lifes little letdowns....[sm=boohoo.gif]

 

I had the same problem on my 07 XL Custom, the dealership i bought it from told me i was running lean. But anyways they remaped, and problem solved!

 

This is incorrect. Your bike is not running lean. On decel unburned fuel is being burned in the exhaust creating the backfire. An EGR valve is the only way to cure this problem but this is not an option on your Sporty. Alot of metric bikes use an Air controlvalvewhich is similar to an EGR, which on decel it opens and draws a metered amountof exhaust back into the engine to be reburned and eliminate the unburned fuel from igniting in the exhaust.The backfire was happeningprior to changing the pipes, you just didn't hear it because the baffles in the stock pipes muffled the backfiring. On my 07 1200N with stock pipes, I occationally heard a bit of backfiring usually when the engine was cold and the F.I. was running in a cold loop operation. You can remap or rejet for the more freer flowing pipes but it will not make the backfiring go away, in fact it is likely to make it worse.