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Main Area => General GS500 Discussion => Topic started by: tripleb on February 28, 2009, 08:22:10 PM

Title: What jets for lunchbox and stock exhaust?
Post by: tripleb on February 28, 2009, 08:22:10 PM
I've searched the forums and found that there isn't much of a consensus on what jets to run with a lunchbox and stock exhaust.  If you have any experience with this setup, please list your jets and any advice you may have.  I'm in Florida so I'm at sea level.  Thanks for your help.
Title: Re: What jets for lunchbox and stock exhaust?
Post by: bill14224 on February 28, 2009, 09:21:55 PM
Hi there.  Elevation doesn't matter much until you're above 2000 feet.  The reason you get mixed advice is because you're going halfway, like me.  You are doing the reverse of what I'm doing, but the result is the same.  Allow me to explain.  I have a K&N drop-in filter in the stock air box with a V&H exhaust, and it runs fine with stock jetting and we have the same bike.  I noticed in your photo you have an E model like me.  If we were to get a high flow air filter AND a high flow exhaust, then we would need bigger jets, but for now we don't.  You see, the amount of flow through the engine is equal to the amount of flow the most restrictive part in the system will allow.  For you, it your exhaust.  For me, it's my air box.  Doesn't matter which, the result is the same.  We essentially have stock intake systems until ALL components are changed with high flow components.

I happen to have a Cobra F1 slip-on I would send you cheap.  If you put that on, you'd have to cut your muffler off with a hacksaw, or use the pipes I have, and you would get a few ponies more IF you put in larger jets, but until you do all 3, air filter, pipes, and jets, you're essentially still stock, and if you upgrade the air box and exhaust without re-jetting you'll be running too lean.
Title: Re: What jets for lunchbox and stock exhaust?
Post by: Weston on February 28, 2009, 09:33:57 PM
Filter is different than exhaust though. I don't know what year your bike is, but if its the old style carb with one main jet I can help. I used a 140 jet as suggested in the wiki. It didn't run right till i rejetted.
Title: Re: What jets for lunchbox and stock exhaust?
Post by: ineedanap on February 28, 2009, 09:59:45 PM
It's in the wiki for both carb styles.  For some reason it's only in the blue table, not the other one too.


http://wiki.gstwins.com/index.php?n=Upgrades.Rejetting (http://wiki.gstwins.com/index.php?n=Upgrades.Rejetting)
Title: Re: What jets for lunchbox and stock exhaust?
Post by: tripleb on March 01, 2009, 05:17:44 PM
so you suggest I run a pilot 40, main 140, 1 washer with 2.5 turns?
Title: Re: What jets for lunchbox and stock exhaust?
Post by: jdw03n on March 01, 2009, 06:01:27 PM
I asked the same question about three months ago, and I'm in Tallahassee.  From Buddha, carb god himself, I got some general advice, but most folks haven't had much success with stock exhast and lunchbox, from what I've researched. 

So my lunchbox is still sitting in my room until I can afford a new exhaust system.

PM me and let me know what success you have, if you try this.