Bandit Alley

GENERAL MOTORCYCLE FORUMS => GENERAL MECHANICAL & TECHNICAL => Topic started by: BLK on June 02, 2008, 01:47:18 PM

Title: Exhaust Popping on Deceleration.
Post by: BLK on June 02, 2008, 01:47:18 PM
Been doing some light reading here on the board and am starting to get the feeling that the really cool popping and rumbling sound my exhaust makes when I come off the throttle might not be an intentional design feature of the muffler but rather an indication of something less than ideally tuned in the bike.

Now, I know you are “supposed” to do something or other to the carbs whenever you change your muffler but I always thought that was more of a recommendation rather than a necessity. Meaning, sure, there’s a performance issue but the difference in performance would be so negligible as not to be noticed by such a casual rider as myself.

Besides, the rumbling and popping sounds so cool.

My question is this: Is that sound an indication of my carbs needing adjustment? And if so what harm is it doing?.

The Particulars:
Replaced the stock muffler with a SuperTrapp. Everything else on the bike is stock – engine wise that is.

blk
Title: Re: Exhaust Popping on Deceleration.
Post by: Snubnose on June 02, 2008, 04:12:22 PM

My question is this: Is that sound an indication of my carbs needing adjustment? And if so what harm is it doing?.
The Particulars:
Replaced the stock muffler with a SuperTrapp. Everything else on the bike is stock – engine wise that is.
blk

I get that too , especially on hard decel, Im told that doing the PAIR removal system kit helps. I had the whole holeshot stage 1 jet kit in and it still popped on decel. I'm going to order the PAIR system removal kit also.
Title: Re: Exhaust Popping on Deceleration.
Post by: wizzobeer on June 02, 2008, 08:30:05 PM
Snub, Dale charges close to $50 bucks for the kit. If you want you can look at mine and get some one to cut some steel for you.
Title: Re: Exhaust Popping on Deceleration.
Post by: Mongo on June 02, 2008, 09:15:47 PM
Snub, Dale charges close to $50 bucks for the kit. If you want you can look at mine and get some one to cut some steel for you.

Did mine a few years back out of aluminum!

I knew I was going to spending some time in the tooling department at work so I stripped one of the tubes off my bike and used it as a template.

I found a good chunk of 1/8" thick aluminum stock in the scrap been and sheared down some 3/4" x 2 1/4" pieces. A little time with a scribe and a   duplicate punch and the layout was complete. Followed by a trip to the drill press and some shaping on the disk sander and this is what I came up with!

(http://i23.photobucket.com/albums/b393/mongo995/CIMG2414.jpg)(http://i23.photobucket.com/albums/b393/mongo995/CIMG2413.jpg)

The crap that came off!

(http://i23.photobucket.com/albums/b393/mongo995/CIMG2415.jpg):scaredmouse:
Title: Re: Exhaust Popping on Deceleration.
Post by: wizzobeer on June 03, 2008, 01:04:18 AM
Mongo, I painted mine with a high temp black rattle can and they just blend in
Title: Re: Exhaust Popping on Deceleration.
Post by: PaulVS on June 03, 2008, 01:08:29 AM
The Bandit is way lean from stock.  Adding a more free-flowing exhaust without a jet kit only makes things more lean... which results in the decel popping.  It'll still give more performance, but a good jet kit is the finishing touch.

With a full Muzzy exhaust system, stage one jet kit, and PAIR removal....  I have almost zero decel popping.  The PAIR removal was the third installment, and it only gave a very minor reduction to what was already a near perfect tune.

So in my opinion... PAIR removal helps... but if you have an aftermarket exhaust... a well-tuned jet kit is the numero uno solution.
Title: Re: Exhaust Popping on Deceleration.
Post by: Mongo on June 03, 2008, 08:18:21 AM
a well-tuned jet kit is the numero uno solution.

Paul is right I still had a decel pop after the pair removal the addition of Dale's stage two air box and jet kit made that problem go away!! :motorsmile:
Title: Re: Exhaust Popping on Deceleration.
Post by: pmackie on June 03, 2008, 12:51:15 PM
Quote
My question is this: Is that sound an indication of my carbs needing adjustment? And if so what harm is it doing?.

Pretty common, and shouldn't cause any particular problem.

As the guys have said though, the bike is running lean, and you can expect better performance with a jet kit.
Title: Re: Exhaust Popping on Deceleration.
Post by: Blade on June 04, 2008, 01:44:06 AM
The reason you get decel popping is because of unburnt fuel in the exhaust system and the addition of air through the P.A.I.R. system. This is normal but anoying. A P.A.I.R. kit will usually fix this.