I'm reading an article about carbs, they mention main and slow jets. The main jet is for wide of throttle? Or is there a certain RPM or throttle position it will take over from the slow jet? The slow jet is for small to mid range throttle?

Lets say I was lean at idle or low throttle, would I swap out the slow jet or adjust the idle screw? If I was rich at wide open throttle I would put in a smaller main jet right?

In a carb kit do you get main and slow jets? I always hear people talk about replacing jets, do they only replace the main jet? I would think the slow jet would play an important roll in jetting. Do our carbs have slow jets? Maybe this carb article is not what I should be reading? This is the article


Here is another link about carbs and jetting, its more comprehensive. I'm going to read that now.

 

Slow jet is for idle only. When the circuit is closed and idleing.

 

When you say circuit you don't mean something electronic. You mean a pathway for the fuel to flow?

 

Yeah, I should have explained that part better. When I said curcuit I meant fuel and air flow. When idleing the fuel is shut off through the main jet by the needle jet. The fuel passes through the slow jet at this time.

This is why when guys add aftermarket mufflers and let off the gas all at once from a full throttle they get a backfire. It goes from a wideopen main jet curcuit to a closed one an the slow jet takes over. It "slow jet" doesnt supply enough fuel for the air thats there. It then cant make combustion and expells the gas out the muffler in the form of a backfire.

 

ahhh, makes sense. I have heard of a needle jet called a bleeder, it has holes in it to allow for more fuel?? Its been said it will increase mid range power. Do our Kawi's have the normal needle jet or do we have this bleeder type? If we don't have it, has anyone tried it?

 

Slow jet is for light throttle applications. Eg ~5% to 20%

Idle Air Bleed Screws are for Idle Rich/Lean settings. Eg Idle

 

I wont edit my above post but I wanted to clear up what is misleading. The way I made it sound is you can "adjust" the slow jet. You cant adjust it but you can change it like the main jet can be changed. When you get the backfiring you can adjust it out "or at least I have" with the mixture screw. I call it the mixture screw but I guess its proper name is the pilot screw. I have fooled with jetting a lot on my old Kodiak and the P650 but Im no where near an expert or claim to be.