I was just wondering if anyone knows the specs on the stock needle in a 2002 Warror? I am having some issues with backfiring and cutting out right at 1/8 throttle, and adjusting the air screw is having little to no effect.

I read that at this throttle position, the needle diameter has the largest effect on the mixture. I'm pretty sure the taper is fine, I just need a slightly narrower diameter needle....but I have no idea what it is...

 

Anyone?

 

the stock jet needle on a warrior is 145. if its backfiring wouldnt it be running to lean? in that case you would need a larger jet size

 

Yes, I believe I am running lean at this throttle position. According to the following Quick Jetting Guide, I either need to change the throttle valve cut away (slide) or go with a different diameter needle. Since my 1/4 to full throttle response is good, I think my taper is fine.

Is the 145 number you quoted for the jet, or the needle? According to that guide, the last two digits of the needle number represent the diameter of the needle. From what I gathered, the smaller the number, the richer the mixture at lower throttle positions. So if I currently have a 1.45, if I went down to a 1.34, it should solve/help my lean condition at 1/8 throttle...?

 

you lost me....

 

the stock warrior main jet is a 145 and the stock pilot is 42. stock needle clip position is the middle groove and the stock air screw position is 2 or 2 1/2 turns out.

hope that helps

 

What kinds of mods have you done over stock?
Try lowering the clip on the needle, that will raise it up and make the midrange richer.
You say the mixture screw has no effect, at all? It wont make the rpms drop as you adjust it? Or it just wont effect the problem?
When does the backfiring happen.... going on the throttle or coming off the throttle? Usually if there is a hesitation, going into the midrange, its a lean pilot circuit, either pilot too small or the mixture screw is out of adjustment.
Try using the choke, full on, for a test run. See if the backfiring and hesitation get better or worse. If it gets better, then for sure youre lean.

 

I haven't made any mods...except, I *DID* raise the clip on the needle, because my plug was pretty dark from running at mid throttle all the time. The plug looks great now. I had this same problem before I changed the clip position, and it didn't really affect it either way.

The mixture screw has no effect at all..assuming I'm turning the right screw. It's the screw thats really hard to get to, directly under the intake, between the carb and the head....Maybe I just need a richer pilot jet?

Yes, when the engine is cooler is when I have the problem, and playing with the choke virtually eliminates the problem at low throttle positions. I can't go over about 1/4 throttle then, because it makes the midrange choke out.

The engine seems to run fine at an idle, and slightly off idle. However, it's just between 1/8 and 1/4 throttle that I have a problem....

 

carb
The mixture screw is # 16 in this view.
Start at 2 turns out, and while idleing warm, adjust it in, until the rpms drop. From there , count the turns, going out, until the rpms drop again. Midway in between those points is the place to be.
If it doesnt drop rpm, going in, the pilot jet is too big. Which i really doubt, because i assume its stock size.
If it doesnt drop rpm, going out, then the pilot jet is too small.
Is the gasket at the top of the carb, in good shape? Its # 3 in the picture.

 

If you are running with stock exhaust you should not need to rejet. but if you want to rich the mixture you want to jump to a larger diameter of jet size maybe a little not too much or then you will run rich.