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Discussion Starter · #1 ·
Ok..i did the carb mod, cut the spring and driled the holes.

A friend told me to turn the air screw out 2.5 to 3 turns. Where is the air screw..i need a picture! LOL not to bright with carbs!

What is the stock setting on the air-screw? will it hurt to drive as is?

Also..when i took the needle out and such i was real carefull, but im not sure if i got the order right or not with the washers. There was a small grey washer, does it go in before or after the needle? Cuase im sure i took the top off, then pulled out the SMALL spring, then the needle, then came the small grey washer..but again, im not sure. ANYONE??
 

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On the bottom of the carb, there is a small hole that has a brass plug in it. You have to use a drill &/or hole out to get the plug out, as it is flat. there is no slot/hole for a screwdriver, allen wrench, etc. Pull it out & the screw will be under it.

Now, what exactly is the carb mod you are talking about? The first time I adjusted my needle, I saw the spring you are talking about, but how much if it do you cut off? Also, what, where and how big are the holes you drilled?
 

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Discussion Starter · #3 ·
This is the mod right here..

http://thestevensons.homeip.net/predatorposts/PREDATORCARBSPRINGANDSLIDEMOD.htm

Copy and paste the link...
 

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Thanks.
 

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Discussion Starter · #5 ·
any one else??
 

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We're talking about the pilot mixture screw right? And it's a fuel adjustment not air. It's located near the back and if you turn it out you will add more fuel. Stock is 2.5 turns out, It's where I have mine and it works great.

CJ
 

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Discussion Starter · #7 ·
IM not sure, my friend said and i quote

"It's under the cap (brass) the airscrew remove it then turn it in until it gently seats then turn it out 3 turns."

So is this the air screw or the pilot mixture screw?
 

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If you look on my profile, I put up a picture of the bottom of the predator carb I found somewhere. In the pic below the float bowl there are 3 circular bosses. The one in the middle sticks out and has a brass plug with a small hole. This is the air mixture screw. above and behind that is another solid brass plug it looks like anybody know what that is?
 

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Discussion Starter · #9 ·
Cool..so the stock setting is 2.5 turns? So i'll probably be ok where im at now then..Thanks!
 

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CJ that screw you are talking about, the one that is under the brass plug that has to be drilled out to make an adjustment with, is a FUEL SCREW!!!!!!

Fuel screws are MUCH more touchy to set right, compared to an air screw. A very small change in fuel screw setting will result in large changes in the WHOLE carb set-up.

If you mess up the fuel screw setting you can throw off the whole carb! So be careful as to how much you change at any one time. Try small changes like 1/8-1/4 turns at a time!!


A simple way to tell what is a fuel screw and what is an air screw is to remember if it is on the air box side of the slide it is an air screw and if it is on the motor side of the slide it is a fuel screw.
 

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This is the air screw:
Mine is out 3 turns, helped alot, though I'm going to a 50 piolet tonight.
 

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That's a link to a server at my house. Apparently it's down. I'll have to fix that.
 

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polarisbob,

Yes you are right it adjusts the fuel.

So what is under the brass plug behind the mixture screw we are talking about?

CJ
 

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Erik, I hate to Tell you this, BUT that picture is 100% WRONG!!!!!!!!!!!!!!!

That is a fuel screw!!!!

Just to make sure we are talking about the same thing. Polaris, in their factory service manual, calls this air screw a "pilot mixture screw"!! This is what is circled in the picture!!!!!!!!!!!!!!!

It is dis-information like this that really messes up people!!

There is a reason why the mfg puts the "fuel screw" behind a brass plug/cover, and that is that most back yard tuners have no clue as to how to tune it the right way, and if tuned wrong the WHOLE carb setting is thrown off.

There is a larger issue also and that is trying to meet the government emissions requirements. But that is a whole different topic.


If the question is , Can a person get better performance by adjusting the fuel screw for "his/her" riding area and riding style?? Then the answer is YES 100% YES.

But you HAVE to have the knowledge as to what you are turning/ tuning before you start!

For your information there is NOT any "air screw" on the 2003 Polaris predator stock factory carb!!

While there are air jets that can be changed, note these air jets are fine and don't need be messed with, there is not any kind of adjustable air screw any where on the carb.!!!!!!!!!!!!!


CJ in your posts, you have posted that the screw we are talking about is both a fuel/pilot mixture screw and that it is also an air screw.

"
CJ
User
(Predator Owner)

Member No. 255
Registered: 05 Apr 03
Posts: 22
From: Richmond, Virginia



We're talking about the pilot mixture screw right? And it's a fuel adjustment not air. It's located near the back and if you turn it out you will add more fuel. Stock is 2.5 turns out, It's where I have mine and it works great.

CJ



This post was edited by CJ on 20 Oct 03 9:26 AM . "


I am not trying to bash anyone just to make sure we are all talking about the same thing!!!


bob out!!!!!!!!
 

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CJ, not 100% sure, I have not taken them out, but I think they are where the MFG had to drill passages in the carb for air circuits or some such and then covered them up so that the carb will work.

It is very common to find these kind of plugs on auto carburetors, and they are just to cover passages that are machined in to them after the casting process.
 

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Bob,

Again, your 100% right, the screw in question adjusts the fuel, no one is arguing that. Why the manual and other people call it an air mixture screw is beyond me. We're all talking about the same thing.

You really make it sound like the screw is magical...its nothing to be scared of. Your right, small adjustments is the key to making progress with tuning.

CJ
 

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CJ ...lol... Did not mean to make it sound magical..lol..

It's just that most people are used to tuning the air screw on their 2 strokes and a large amount of turns can be made, to a air screw, with out really hurting the performance of the bike. Where a small turn of the fuel screw will have large changes on the performance.

It is a factor of what the screw is controlling and how the air fuel ratio is affected.

With the "perfect" A/F ratio being 14:1, there are 14 parts of air to 1 part of fuel. So with the air screw you are changing the air ratio a lot less than if you are changing the fuel screw and the fuel ratio.

Small changes in the fuel screw will have large changes in the fuel to air ratio, that is all I was trying to say.
 

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so is it true that you need to drill that plug out and set it at 3 turns out when adding a clamp on filter or not? What is the stock setting?
 

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Discussion Starter · #20 ·
Thanks for the help guys!
 
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