(TL;DR on bottom)

First of all, I popped the tops off of my carbs today to check my needle shims. I found out that I had NO idea what I was doing when I first rejetted. So, I re-shimmed and went on my way. I also found out that I'm missing the little o-rings on each side of my carb tops.

With that information in hand, I have an afterfiring problem. Well, maybe not necessarily a problem, which is why I'm asking. I have a Jardine and pods, and my exhaust pops quite a bit on deceleration. I've jetted according to the matrix, and have played around with the mixture screws (2 to 3 turns in .25 increments). 2.5 seems to be where I get the least popping. I have also triple checked my header bolts, so I think I can rule out an exhaust leak. It also idles fine and runs like a dream, so I don't think I have a vacuum leak, either. Carbs have been synced, and valves were within spec as of spring.

TL;DR: Will a performance aftermarket exhaust pop a lot on deceleration if properly tuned? Will those little o-rings cause this issue if they're missing?

I believe I have read that on this forum... answering being yes, especially if the pair system is intact.  Maybe some others can say why or add info to that to confirm? ... but I really don't know if its true, but I've read it on here before and I'm not sure I remember the source 

- Bboy

My hd did. my gs' not so much one had a vance an dhines, other one was punched. ( stock)

Quote from: BockinBboy on October 02, 2013, 09:41:22 AM
I believe I have read that on this forum... answering being yes, especially if the pair system is intact.  Maybe some others can say why or add info to that to confirm? ... but I really don't know if its true, but I've read it on here before and I'm not sure I remember the source 

- Bboy

That's another puzzling point. I supposedly have a 2004, according to the VIN. But I have no PAIR system of which to speak. There aren't even block-off plates; they're sealed on the block itself. Perhaps the PO swapped motors or something. Not that it really matters. That's just one less thing to worry about lol.

As far as the exhaust goes, it's not really bothersome. I just want to make sure I have it tuned properly. I have severe OCD when it comes to my vehicles. They HAVE to be in top shape, or it really bothers me. (I have a 2005 Stratus 2.7L sludge machine with 108k that runs like new.)

You need to replace the O Rings on top. That can make it misfire.
Cool.
Buddha.

Awesome-sauce. Know where I can find some of those little guys?

Quote from: JAS6377 on October 02, 2013, 01:37:21 PM
Awesome-sauce. Know where I can find some of those little guys?

Take the carbs and match it @ autoparts store. Buy neoprene/BUNA O rings, not rubber.
Cool.
Buddha.

Alright. How big are they supposed to be? Just big enough to fit around that little post thing on each corner of the carb cap?

Quote from: JAS6377 on October 02, 2013, 05:00:18 PM
Alright. How big are they supposed to be? Just big enough to fit around that little post thing on each corner of the carb cap?

They should leave that air hole open, the rest they should seal up against the top. I use pretty fat ones, stock is rather thin. The smallest in a 432 piece kit from harbor freight works fine. Auto shops have those kits but never use the tiny ones. They may give you some.

Cool.
Buddha.

I just took a look at the parts list and pictures for the K4 carburetors, and it shows no o-rings under the caps... So,I guess I'm not missing any o-rings, as I didn't have them to begin with..?

Alright... In light of recent events, I just need something to do to take my mind off of things.

I have found that I have 3 lines that are questionable under my gas tank. My valve cover hose is currently unfiltered, which I should probably fix ASAP. The hose connected to the top "T" (that rubber connection between the carbs) has a small breather filter on it. The lower "T" hose is currently connected to what I believe used to be the airbox drain hose (the one that has that little rubber cap on it). Should I be looking to do anything else with these hoses that may help alleviate some of this afterfiring? I may also, if I can get the time this week, do another valve check and carb sync, just to double check everything if no solutions come up.

OK 01+ bike has no Orings on top.
So that not your problem.

Hoses ... valve cover vent could be open, ot fitted with K&N type filter ... Or fitted with PCV valve.
The top T should be relatively open to atmosphere. Filter may be OK, but it should flow air in.

Bottom carb T ... should get fuel from the petcock.

Cool.
Buddha.

I was slightly mistaken when I said the lower "T". The fuel line is obviously hooked up correctly, as the bike has been running strong. There is a second rubber T connector between the two carbs that I believe used to be connected to the airbox, but I'm not sure.

The "Ts" that I'm talking about are numbers 48 and 50 in this diagram:

48 is vacuum, had to go to petcock.
50 is the vent and I think its just filtering the air coming in.
Cool.
Buddha.

Quote from: The Buddha on October 07, 2013, 03:52:35 PM
48 is vacuum, had to go to petcock.
50 is the vent and I think its just filtering the air coming in.
Cool.
Buddha.

Maybe not, the 50 T thing is to the rollover valve whatever that is, not vacuum.
Looks like vacuum comes off the right carb - 44 goes to it.
Cool.
Buddha.

I'm thinking that rollover valve is probably something like a PCV valve to help keep proper vacuum pressure..? Idk. The valve is there lol. I'll play around with 48, plugging it and whatnot, and tinker with that filter doohickey. You've piqued my curiosity now lol.

Edit: It seems as though I was halfway right on that valve. It's to prevent excessive fuel leakage, apparently. So, it is a one way filter. Who knew?

Quote from: JAS6377 on October 07, 2013, 05:07:03 PM
I'm thinking that rollover valve is probably something like a PCV valve to help keep proper vacuum pressure..? Idk. The valve is there lol. I'll play around with 48, plugging it and whatnot, and tinker with that filter doohickey. You've piqued my curiosity now lol.

Dude PCV valve belongs on an engine vent ... not on a carb vent.
The Rollover valve, essentially is like marvel mystery oil. What it does is the mystery.
Cool.
Buddha.

Quote from: The Buddha on October 07, 2013, 05:09:31 PM

Quote from: JAS6377 on October 07, 2013, 05:07:03 PM
I'm thinking that rollover valve is probably something like a PCV valve to help keep proper vacuum pressure..? Idk. The valve is there lol. I'll play around with 48, plugging it and whatnot, and tinker with that filter doohickey. You've piqued my curiosity now lol.

Dude PCV valve belongs on an engine vent ... not on a carb vent.
The Rollover valve, essentially is like marvel mystery oil. What it does is the mystery.
Cool.
Buddha.

I'm well aware of what a PCV valve is... I was just noting a similarity in the fact that they both are one way valve devices. The PCV valve only vents, but doesn't allow intake. A rollover valve does the opposite, and with fuel, not crank case gases.

Oh. And 



Another edit (I seem to be doing this a lot): From the parts diagram that I'm looking at on BikeBandit, it looks like that doohickey really is just a filter. It lists the part as FILTER,2ND AIR.

Did some more research. I found this post, and this how-to from, believe it or not, GSTwins! Go figure. It seems as though my hoses are not the issue here. Both top Ts are air-related. The topmost has the filter, the lower is just left open, and the bottom T is for fuel, as you said, Buddha.

So, onward. I'm at a loss. I guess I'll just take it apart, do a valve check, sync the carbs, and put everything back together. Perhaps I did something wrong the last time. 

A rollover valve does somehting ... danggit ... there is like 300 in the ravine across the street form me ... they must be up to something, Lately I've seen big dogs go down there ... and never be seen again.
Cool.
Buddha.