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change needles?

  • Thread starter Thread starter ap72
  • Start date Start date
A

ap72

Guest
I'm looking at putting on pods on my gs650L and am aware taht the carb jetting will need to be changed accordingly. My question is the Jet kits that you buy come with new needles. I would rather just buy a handful of jets so I could have more to choose from when tuning it ( I plan to use a vacuum gauge and a A/F sensor to tune it- just like all of my cars).

Is the needle that comes with the jet kits necessary or can I use a stock one with pods?

Also which funtion of the fuel curve does it fill? What about the pilot and main jets?

Once I understand which function each of these satisfy I'll be fine. It's not a Rochester, Holley, or Edelbrock though, so its new to me.
 
I'm sure someone else will give an opinion on this but here goes:
The needles are primarily midrange and top end.
Pilots are idle and low speed. Don't forget the pilot air screws.
Mains are midrange and top end.
They all have a direct running relation with each other. They all play together.
I would use the needles that came with the kit. Tapers are probably different than the stock ones.
Trial and error and patience is the key.
Good luck.
 
I prefer jet kits, but you can always try shimming up the stock needle and trying separate main jets, pilot jets, and air jets. Many CV carb kits also supply lighter diaphragm/slide assembly springs to improve throttle response. It's also required you enlarge the vacuum orifice to the diaphragm chamber. My point is there's more to it than mains and needles.
I personally wouldn't run pods with a stock exhaust. They need a free flow exhaust to compliment them. May be questionable results that may not be worth the effort. You stand to lose some low end torque.
The main jet regulates 3/4 to full throttle position.
The jet needle regulates approx' 1/5 up to 3/4 throttle position.
The pilot circuit regulates from idle to about 1/5 throttle position.
There is some overlap effect between the pilot circuit/needle circuit and the needle and main circuits as the needle rises.
 
I know I won't see much of a difference power wise without an exhaust to complement it, but I really just want to get rid of the air box.

Also- while on the subject is it possible to use a 4 into 1 for a 550 on a 650?
 
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