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General Category => Yamaha FJ1100 / FJ1200 Running Problems => Topic started by: Canadian on April 20, 2013, 06:27:41 PM

Title: Exhaust popping
Post by: Canadian on April 20, 2013, 06:27:41 PM
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.
Title: Re: Exhaust popping
Post by: baldy3853 on April 20, 2013, 07:15:48 PM
mmmm   :scratch_one-s_head: Could be sucking air in thru the joins in the exhaust  :empathy2:
Baldy
Title: Re: Exhaust popping
Post by: Canadian on April 20, 2013, 07:36:13 PM
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. :music:
Title: Re: Exhaust popping
Post by: Canadian on April 20, 2013, 07:47:35 PM
 :dash2:
Maybe my distribution was wrong by popping I mean backfire
Title: Re: Exhaust popping
Post by: Arnie on April 20, 2013, 09:03:08 PM
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
Title: Re: Exhaust popping
Post by: RichBaker on April 22, 2013, 10:12:07 PM
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.....