Jets... the basics

3 replies to this topic
  • Thesykboy

Posted October 18, 2011 - 08:16 PM


I've looked over the stickies and was very happy as to how helpful they are in dialing in a carb. However, I'm at a loss when it comes to the jets since I'm not used to there being 4! I'm old school and used to just 2 in a single carb.

In the carb body itself there are 3:

Main Jet
Pilot Jet (or slow jet)
Unknown Jet

In the bowl there is 1:

Leak Jet (I think)

I'm trying to get all the jets dialed in and am aware of which ones the Main and Pilot jets are, but I am not certain about the 3rd one in the body and the one in the bowl? If the one in the BOWL is the leak jet, what is the 3rd one in the body?

  • MANIAC998

Posted October 19, 2011 - 03:50 AM


Main jet/ Pilot jet/ Starter jet/ Needle jet/ Air jet/ Leak jet, there I think that's all of them! Yes, that's a lot of jets, but some of them you don't need to mess with. Main jet, functions just like what your used to on the ol' two smokers. Pilot jet controls idle, and just off from idle throttle openings. Starter jet I think is basically your choke. If I'm wrong someone will straighten me out! Needle jet is the needle that slides up & down with the slide. Air jet, hmmmmmm..... I think this one is part of the starting/idle circuit. So it controls the amount of air bypassing the slide when the slide is closed like during starting and at idle. Again, if I'm wrong, someone will correct me! And the leak jet. Yes, this is the jet located in the bottom of the float bowl. It's part of the accelerator pump circuit. The accelerator pump squirt can be adjusted by changing the size of the leak jet. The leak jet basically, "leaks" out a certain volume of fuel from the accelerator pump circuit, and the rest is squirted into the venturi of the carb. Some bikes squirt too much, so a larger leak is needed to lower the volume squirted into the venturi. Others need a smaller leak so more is squirted. There! See how easy that is!!! Whew!!! I need a beer!!! Maniac

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  • bg10459

Posted October 19, 2011 - 12:06 PM


Air jet, hmmmmmm..... I think this one is part of the starting/idle circuit.

There are two air jets; main and pilot. They control the air to their respective jets. Only the pilot air jet is replaceable, but there's no need to mess with it.

  • Krannie McKranface

Posted October 19, 2011 - 03:09 PM




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