Carb Rejeting?

[Anonymous]

I bought my GS550T two months ago and I'm doing some work to get it road worthy. I have never changed the jets in a carb before and have the following Questions to ask:

This bike has four into one Vance&Hanes exhaust. I have no idea if the person who put it on rejeted the carbs. How can I tell if they did? If they didn't how exactly would I go about changing them? Is there a certain number higher than stock that I need to change to or do I just guess untill it runs right? What carb modifications must I make to install them? If I go to high can I change back to a smaller jet?

ANY info. would be great.

Thanks

MOONSHINE

 

[Anonymous]

OK you will have to just look up the bike you have in a manuel or call someone like a parts dealer for your bike so he or she can look up what jet size came stock in your bike. Then you can look on the bottom of your main jet and it will have # on it for example 117 or something like that.

To get your bike running perfect you will have to just trial and error it. Do spark plug checks on the bike if it is running lean it will be white or very very light colored and if it is running too rich it will be very black and suity. Ideal is a light brown in my book but everyone has thier flavor. Bigger #Jets make it a richer mixture. Smaller # Jets make it leaner.

Carb jets are like screws you don't have to modify anything they just have a bigger or smaller hole in the middle thats all. Once you go bigger yes you can go smaller again.

I wish I could tell you the right jet to use but thats well impossible without trying it out first. Try to see if the plugs look right with the current setup it might save you alot of work.
Good luck on finding your right # Jet!

 

[Anonymous]

Thanks for the info Ryan. I changed the plugs right after I bought it and ran it awhile until I figured out the RR was shot. This is what I can remember from the plugs after looking at them: Cylinders 1-3-4 are all rich(dark sooty) 2 is just about perfect maybe, alittle lean (light brown white).

 

[Anonymous]

I think there is a misconception that all aftermarket pipes require richer jetting. Many of the pipes out there are sold as street or sport types rather than full on race headers, and these may actually operate fine with the stock jetting, or may need only slight changes to one or two of the carb circuits. I would suggest finding a shop in your area that has a dyno with an exhaust gas analyzer. This way they can tell you if your bike is running rich or lean at certain throttle positions, then you'll have an idea where to start.
Axel

 

[Anonymous]

I did some rejetting on my bike, which has a Vane and Hines pipe on it.
I called their tech support up and they were very helpful with recommending what jets you should have. They will certainly get you in the ballpark. My stock mains were 107.5, V&H recommended 114, I needed 117.5`s. They told me they couldn`t be sure of what I needed because I had a Wiseco overbore kit in it, but you can see that they were pretty good. Here`s V&H contact info if you need it.
Hope that helps.
Jack

http://www.vanceandhines.com/pages/Tech.html

 

[Anonymous]

Thanks for the info Jack Appel I'll try the link out.