Carb jet setup

[irarref215]

Newbie here, bought an '02 recently. What a basket case it was. No maintenance and ridden in water at sometime. In addition to all the issues that were found, I have added an FMF pipe/header, and a stage 1 hotcams cam. I get a misfire sometimes in idle, but seems to pull well after I got those stock tires off there. Is there something I should do to adjust the fuel mixture? I have torn the carb apart trying in my efforts of trying to find the parking brake rev limiter BS, and notice that there is 5 notches on the jet. Should I adjust this with the setup I have? I tune turbo GM engines and usually use wideband O2. What do you guys use for tuning, temp? or is it hit and miss. Give me an idea what I need to do. Thanks guys!

 

[yamarider]

First, welcome to the site!

Did you add a full exhaust system and cam without rejetting it at all? If so, stop riding it until you get it jetted properly, unless you want to risk damaging your engine. These things come borderline lean from the factory, so anything that increases flow is going to push it over that line and make it dangerously lean especially as we're getting into the colder weather (i'm not sure where you're located).

You will probably need to go one size larger on the pilot jet (that's why you're getting that hiccup at idle, it's starving for fuel), and probably move the clip down one notch on the needle, and 1 or 2 sizes higher on the main jet. You may be able to get away with just turning the fuel screw out instead of replacing the pilot jet, but anything more than about 3-1/2 turns past from full in, it really doesn't make much of a difference and at that point a richer pilot jet will be necessary.

Most of us will just do the jetting by the seat of the pants. I've tried jetting based on spark plug color, but with modern fuels that burn cleaner than the stuff we had a few years ago, sometimes all that does is cause confusion. Although it can still give a decent baseline indication, if the insulator is pure white you're probably looking at a lean condition, and if the insulator is dark it's probably running too rich.

Sounds like you got a typical warrior. People buy them, beat the crap out of them for 5 or so years, and then sell them when they start having mechanical problems from lack of maintenance. Warriors are one of the most reliable quads ever built, but because people neglect them so frequently, it makes it look like they're unreliable pieces of crap at times.

If you have any other questions don't hesitate to ask, you came to the right place.

 

[griff]

Hmmm, the full exhaust system wont have a big effect on jetting unless he's also modified the airbox/intake to flow more. The air has to get in, before it can get out

Has anything been done on the intake side? No box? Modified box? Aftermarket air filter?

If its been sitting for any amount of time, make sure the pilot jet and main jet are clean! Remove them from the carb, soak'em in carb cleaner, and blow them out using an air compressor. Water contamination (and water contamination from Ethanol content in fuel) is slightly corrosive, and oxidizes the aluminum in the carbs to the brass jets. Its usually whitish, wet-powdery stuff, that can also have a greenish tint (from then ethanol).

 

[darebee]

The hotcam is likely going to make it breath a little deeper but the intake needs upsized to accomodate fosho

 

[irarref215]

OK thanks yamarider. No scientific way to insure the correct fuel mixture. Wanted a sure fire way (no pun) to get an indication of a lean condition. Turned the pilot out 1 full turn, now no hesitation off idle and so backfire into the carb. The pilot is now out 3 turns and seems to run good, no backfire or hesitation.

So, am I correct that I need to move the needle out a notch? I am in the middle of five notches. Plug looks good, center electrode ceramic not discolored nor white. You are correct on the lack of maintenance. I had a hell of a time replacing the bearings, and the brakes. Is that a sliding pin caliper they use on the brakes? Should that move freely in and out? If it is frozen ( threads are not frozen), should I work it out to remove and lube? Thanks for all your help, it sure is nice to have a good bunch of guys on a forum to help a noob like me. Eric

 

[DeadLastRacing]

The breaks do use sliding pins to hold the pads in.....those should not move once there in place. I believe there hex head pins. I also put some break pad grease on mine when I install new ones. I makes them move a lil better and also allows for the pin to go out and in better. Hope that helps. The rear set up is almost the same but uses a slack style mounting bracket. The bracket should have a little play in it but not the pad pins.

 

[yamarider]

It is possible to use a dyno, wideband o2 sensor, and all that happy crap to get the jetting dialed in perfectly, but I for one wouldn't spend that time on a warrior or any trail ridden atv for that matter, i don't see how it would be worth it. Especially with the stock carb, it'll never be perfect with the stock carb.

Another good indication of a lean condition is a glowing headpipe. It's normal for them to glow enough that its barely visible in the darkness, or to glow after idling for a while because of the lack of air movement, but if you notice it's really glowing hot, like more than the first couple inches of the pipe, i'd definitely look into it more.