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Main Area => General GS500 Discussion => Topic started by: RsRide on August 21, 2008, 05:38:10 PM

Title: Deceleration Backfiring
Post by: RsRide on August 21, 2008, 05:38:10 PM
I know there have been a lot of questions about this but I haven't found the answers Im looking for. I have a '93 GS with 8k on it. I get quite a few backfires when decelerating fast. I am looking into rejetting and was wondering what people recommend.

I was also wondering what the stock main jets are.

I am at 7000 feet. I do have a KN Lunchbox.

Any suggestions would be great. Thanks.
Title: Re: Deceleration Backfiring
Post by: wildbill on August 21, 2008, 05:45:28 PM
u need to rejet w/ a lunchbox... put stock filter back on.. your sucking too much air. running rich. floats could be off too.
Title: Re: Deceleration Backfiring
Post by: dgo99gs500e on August 21, 2008, 06:46:19 PM
 he is at a higer alitude and if the stock jets are in it then yes he is runnig rich but with the lunch box in he should be running a bit lean i just did the same thing but i think the prevous owner had put some different jets in it beause it was running way way rich plugs were black black with out the k and n i put the k and n in it it is running spot on.  So with that said with stock jets he is probably runing lean right now and that is what is causing the back fire also i do think that the floats may be off but i dont think he is running rich more air = less fuel = lean thats just my .02 cents i could be wrong o i am at 6512 feet above see level
Title: Re: Deceleration Backfiring
Post by: ecpreston on August 21, 2008, 07:53:15 PM
Loud pops under decel? That's a feature not a bug!  8)  Accompanied by flames would be preferable of course.

(http://www.struck.us/BikePics/Hungary/Hungary%2004%20Cool%20Bike.jpg)
Title: Re: Deceleration Backfiring
Post by: GeeP on August 21, 2008, 09:35:13 PM
Popping on decel is entirely normal and not indicative of a fuel scheduling problem.
Title: Re: Deceleration Backfiring
Post by: wheels on August 22, 2008, 01:31:48 AM
I had the same problem when my K&N air filters were really dirty.  I cleaned them and the backfiring stopped completely.
Title: Re: Deceleration Backfiring
Post by: RsRide on August 24, 2008, 09:44:31 PM
Cool. Thanks everyone. I'm going to check some stuff out. Does anyone know what the stock jets are???
Title: Re: Deceleration Backfiring
Post by: lilbill on August 25, 2008, 02:06:41 PM
Pilot: 37.5 Main: 122.5 for stockers
Title: Re: Deceleration Backfiring
Post by: mi_dude on August 25, 2008, 05:57:53 PM
For the past year I have had backfiring on decel.  Earlier this year I started to have problems with the bike not wanting to idle or constantly needing to change the idle air screw.  I finally got fed up and took the carbs off and thoroughly cleaned them.  Bike is running great and not one backfire.

My 2 cents, the backfire is definitely due to being lean.  Since it is on decel, the main jet size shouldn't matter (at least for backfiring).  It's really a function of the idle fuel/air mixture.  In my case, I think I was lean due to debris cutting the idle fuel flow.
Title: Re: Deceleration Backfiring
Post by: starshooter10 on September 10, 2008, 07:24:10 PM
check your pipes for holes and cracks..

and make sure your header bolts are tight

Title: Re: Deceleration Backfiring
Post by: ohgood on September 10, 2008, 07:55:19 PM
Quote from: GeeP on August 21, 2008, 09:35:13 PM
Popping on decel is entirely normal and not indicative of a fuel scheduling problem.


dayum, hope you got change from that $5 word !