Ok so after an hour of reading all of the search results for rejetting I'm more confused than I was an hour ago. There are SOOO many questions!
It appears that EVERYONE has problems with their carbs after taking it apart and putting it back together, be it for cleaning/rejetting/etc.

My bike has a Muzzy after market exhaust -- I thought it was fine, but now theres a whole list of crap I need to do now? So heres the questions that are confusing me:

1. In what circumstances is rejetting not only necessary, but recommended?

2. What are the pro's/con's with "lean" vs "rich"

3. How will rejetting affect gas mileage?

4. What exactly do I need other than jets for an optimal rejet? (K&N Lunch box, exhaust?)

5. What will happen if none of number 4 were to be done?

I ask these questions because it seems that once you do ONE thing to the bike, it snowballs and affects the entire machine. And I'd like to do it without being off the ride for longer than I need to (I dont want a 4 hour job to become a 2 week deal for the lack of parts).

It seems if I were to go about cleaning, taking apart, rejet, ANYTHING I'm gonna screw things up

1. Whenever the fuel mixture is not ideal jetting is the main way to control the mixture with carbs.  A poor mixture can be caused by a change of air filter, exhaust or even climate.  The jets in a carb control the amount of gas which reaches the cylinder to be burnt.

2. Check http://cgi.stanford.edu/~sanjayd/gs500/Upgrades/Rejetting-LeanOrRich? and
             http://cgi.stanford.edu/~sanjayd/gs500/Upgrades/Rejetting

3. When rejetting usually the size of the jets goes up i.e more fuel so fuel mileage will go down...but I don't think it's considerable.  Someone else with a more aggressive jetting will have to chime in on that one.

4. Nothing.  That's entirely up to you.  If you plan to eventually do that stuff get whatever you can right now so that you can make one change since each thing (lunchbox, exhaust...) will require a different mixture. 

5. I rejetted mine with stock everything since it is a bit lean from the factory and it's great!  Again, jetting is nothing more than an attempt to optimize the air/fuel ratio in the engine.  An easy way to check the mixture is to follow the link to the spark plugs in the first link I gave you.

The first time I worked on carbs was on this bike.  They are very simple...I know it seems overwhelming at first, but really once you crack one open it's not that bad.  One main thing to be careful of is not to loose a tiny little o-ring that sits under the black diaphragm cap on top of the carb...it's only about 1/8 in in diameter!

Best of luck to you and don't be afraid to ask more questions

You have lunch box and exhaust and you've not rejetted - I'd almost guess it will run so badly if you have not that you'd not be asking at all.
So tell us the history of the bike. Like PO did it, or you did this but some thign was laready done etc etc.
Cool.
Buddha.

Quote from: The Buddha on July 24, 2008, 05:42:24 AM
You have lunch box and exhaust and you've not rejetted - I'd almost guess it will run so badly if you have not that you'd not be asking at all.
So tell us the history of the bike. Like PO did it, or you did this but some thign was laready done etc etc.
Cool.
Buddha.

No, I just have new exhaust and read that once you do ANY of those things then you need to do the others (rejet and get lunch box in my case). Who's PO?

Thanks for the info lilbill, I'm starting to look more and more forward to modding this baby!!

OK a stock bike, could be rejetted. A pipe = definite rejet. However you can run a pipe with stock filter etc. Run 125/40/1 washer 3 turns on mix screw (its an 89-00 bike right).
I sell kits for doing that - only the parts you need. $22.
I can do it for you - send me carbs, I also can trouble shoot other parts of the bike sometimes with just your carbs - $45 and return shipping for this.
You can run just a pipe and jet it right for that. No problem. Lots of people do that.
Cool.
Buddha.

Ok, so slapping on that Slip on Muzzy would be considered grounds for a rejet? Just to get a more clear understanding as to the mechanics of it, what exactly is so special about the pipe that needs rejet?
I have a 2006 GS, and as I understand you havent made kits for 2001+ yet but will in the future? How much labor do you charge?

Muzzy on there and rejet - I could do the 04+ for $45 but I dont have kits yet. I am unable to find the right mids - I want 1 size up mids, not 2 sizes up. I also have to test ride a bike several 100 miles in varying conditions before I conclude its good.
I will get started on it when I finish the bike I am working on.
Cool.
Buddha.

Quote from: The Buddha on July 24, 2008, 09:31:37 AM
Muzzy on there and rejet - I could do the 04+ for $45 but I dont have kits yet. I am unable to find the right mids - I want 1 size up mids, not 2 sizes up. I also have to test ride a bike several 100 miles in varying conditions before I conclude its good.
I will get started on it when I finish the bike I am working on.
Cool.
Buddha.

So you dont rejet the 01's and above yet?

I can, I just dont unless someone was really having trouble. I need to run the jets I will use and get the right setup to get it perfect.
Cool.
Buddha.

I have ran my 04 with a slip-on and the bike ran fine I did open the mux screw a lil to fix the leaness at idle and such.

I have a2005 with a K&N lunchbox and jardine exhaust


I just put in 20 pilots, 65 mid mains and 145 main jets and she runs sweet, I notice no difference to fuel economy if I'm light on the throttle, but she does use more fuel than stock if i ride her hard (Dirrr!).

No washers ? Yea, I just do what is in the FAQ. I need to have tested it to actually feel good about doing it to someone's bike y'know. But If you are really in trouble, I'll definetly check and fix it for you.
Cool.
Buddha.

I did no other adjustment to my carbs other than to replace the jets and she runs sweet