Anyone real sure about the jets on the Predator carb???? There are three jets inside. Pilot, main, and ??? The problem I am having is that when I let the bike cool down over night I have a real hard time getting it started. I usually kill the battery and have to jump start it. I know that the idle portion must be too lean be cause when I take a more restrictive filter and put it on it will start. Once it is warm it runs great. Ok to the question at hand??? Of the three jets the one in the center is the main at 150 stock then there is another one to the side that is 45 stock and is long and perferated then there is another one to the rear of the main I believe that it is 42.5 stock and looks like the main (dimensionally). I think that I have been changing the wrong jet when I have changed what I thought to be my pilot. I changed the one that is long and is numbered 45 to a 50 but it doesn't seem to make any difference one way or the other. The question is which one is which?

 

Not sure on the Predator jets sizes, but I know some of the different jets. The main is inside the float bowl. The pilot is in the side and has the little holes in it. The jet needle is in the slide of the carb. The needle jet is the tube that the needle jet slides into. The knurled screw that adjust the idle air is the idle air screw or the idle enrichner screw. Here is how they work.
0 to 1/4 throttle use pilot air screw. turn in for richer out for leaner a little at a time.
1/4 to 1/2 throttle is jet needle.
1/2 to 3/4 is needle jet.
3/4 to WOT is main jet.
There is overlap in all of these.
I thinks these are right, any one else if I am wrong please correct me.

 

Then I changed the right one, maybe I just have to go even larger than 50 on the pilot???? Like I said it is a !@#$!@#$ to get started if it even starts at all. Once it is warmed up it barely has to turn over and it starts. I have tried the full range on the idle needle and it still is not easy to start. I understand all of the theories but wasn't sure if I was wrong on something. I must be, it still is not right.

 

Anyone have any ideas? The bottom half of the bottom half of the air box is cut off, main jet is set at 170, needle is one notch from the middle, 50 pilot 3 1/2 turns out on the mixture screw, 4 coils cut off of slide spring, 1/8 holes in slide, W/B exhaust and 87 octane new spark plug. Like I said it runs awesome once it is warmed up??????

 

OK lets try some stuff. First the knurled screw that pushes the slide open is the idle enrichner, lets unscrew that just to the point that the spring tension is zero or the slide is closed( not sure if yours is spring loaded). Next make sure you have a little play in the thumb throttle. This is to make sure your throttle cable is letting the slide go closed, if not adjust the throttle cable so that the slide will go closed. Next go back to your original pilot jet, screw in until it just barely seats. ( too tight could mess up the seat inside the carb) Now unscrew it as many turns as factory spec. I am not sure what that is(usually like 1 1/2 turns out or something). Adjust this in 1/4 or 1/2 turn increments. Screwing in is richer, out is leaner. Little adjustments on this are important. This is a good starting point. Cracking the throttle open a little with your thumb will help you figure out if you need to screw the Idle enrichner in, but with holes drilled in the slide it may not be needed.

 

The third jet you spoke of is the starter jet, fuel is drawn through this jet when the starter enrichment (choke) is on. It is located between the main jet and the fuel screw in the bowl. The 42.5 is the stock size, make sure the plunger is working properly, if the cable is too long the plunger won't lift far enough to allow the proper fuel flow through the starter jet. If that is correct you may need to go larger on the starter jet. I had this type of problem on a 38TMX carb installed on a 400 Scrambler, I had to open up the starting enrichment circuit to allow more fuel to flow, it starts much better now.

 

Fishslab, your fuel screw description is incorrect, you are describing an air screw which is always located on the air filter side of the slide in the carb body. The fuel screw is located between the slide and the engine and controls fuel flow instead of air flow. Turning the screw out will allow more fuel flow richening the mixture and turning it in reverses that (leaner)...

 

I think we are getting closer because I took the carb apart to find out if something was plugged and foud that the choke plunger was caked up with dirt and would not even move let alone be able to be pulled out. Finally after pulling it out and cleaning it it moves freely now but still does not aid in it's starting. So the third jet is a starting jet? Does that function without the choke pulled as well?

 

No the starter jet only works with the choke on..

 

Powerslide, I want to make sure we are not calling the same thing by different names. The Idle enrichner or the enrichner or idle adjustmen screw or idle air screw is what picks the slide up to let more or less air in while idling. It is a knurled eneded screw that you adjust with your fingers, no tool needed. All of mine are located right in the middle of the carb. The pilot jet or sometimes called the idle circuit jet is usually on the air filter side of the carb and allows more fuel in at 0 to 1/4 throttle opening. It has several little holes in it. Turn it in to let more fuel in turn it out to lean it out.