Exhaust popping

[Canadian]

Hello
I just did some carb work on my 89 like setting fuel mixture and sync the carbs. The lady was running rough before I did this (cabs out of sync and mixture screws like 6 to 8 turn out. I set the mixture to 3 turns out and synchronized the carbs ( just bought the Emgo tester from Motorcycle Superstore that works really nice 97$).The bike is running nice throttle response is good the only thing is that she pops now when closing the throttle. she was not doing that at all before. I have a Vance&Hines exhaust so maybe I have to go back to the old setting or do you guys know what else can be done?
Thanks T.

[baldy3853]

mmmm    Could be sucking air in thru the joins in the exhaust 
Baldy

[Canadian]

Thanks
I will check . Any idea what is the best way to do this. I also never touched the exhaust and was riding her for warm up for the work without a single pop.

[Canadian]

 
Maybe my distribution was wrong by popping I mean backfire

[Arnie]

Generally, backfire (popping) on overun is a symptom of too lean a mixture.  You could richen up those idle mixture screws a bit, or put slightly larger idle jets in.  OR, you could leave it as is.... unless its extreme it causes no harm and sounds cool. :-)

Arnie

[RichBaker]

Backfire on decel is normal with most aftermarker pipes. The high vacuum pulls in fuel, but there isn't enough air in the mix for it to burn, because the throttle plates are closed. When the very rich, hot mixture hits the cool, oxy-rich air at the end of the exhaust it burns, producing a cackling noise.....