Poor idle and starting. Is my jetting wrong? - Yamaha ATV Forum
 
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post #1 of 5 Old 09-09-2019, 09:01 AM Thread Starter
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Poor idle and starting. Is my jetting wrong?

I have a 2003 Warrior 350. It has a k&n air filter and FMF exhaust pipe. Iím having trouble getting it to run smoothly. It does not idle great and stalls, hard to start. I have to keep the idle really high. It runs just okay at full speed. I get some popping out the exhaust sometimes. Iíve been trying to adjust the air/fuel mixture screw but that doesnít seem to be helping. Iíve tried from Ĺ turn to 2.5 turns out. Iím now wondering if I need to change the jet(s)? Iíve cleaned the carb twice and it helped slightly but didnít fix the problem. Currently my main jet is 145 and the small jet is 42.5

To me it seems as if itís not getting enough gas.

What is stock jets?

Would the air filter and exhaust affect the jetting?

If so what jet(s) do you recommend?

Iím in Canada in the prairies so itís low elevation and 70f average temp.

Also, if I need to change the jets do I buy one from the dealer, online, or is a kit better?
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post #2 of 5 Old 09-09-2019, 10:27 AM
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sounds like you are lean ad need to rejet? did the problem start after the pipe and k&n? if memory serves that is stock jetting and would be lean with your mods. if you are not familiar with jetting a great place to start is sigma jets. dyno jet also makes a warrior kit but they are not my favorite. they have an awesome web site and all you do is plug in your machine and mods. they make a kit just for your machine with jets above and below for fine tuning. i have done a lot of jetting and i still use them because it is cheap and easy. if you dont want to use the kit go 1 up on the pilot and a 150 to start on the main. that should get you close. after that you will have to make some runs and read the plug to dial it in. ( that is why i use the kit, by the time you buy 3 or 4 plugs and a hand full of jets the kit is cheaper )
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post #3 of 5 Old 09-09-2019, 11:00 AM Thread Starter
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Originally Posted by cory52000 View Post
sounds like you are lean ad need to rejet? did the problem start after the pipe and k&n? if memory serves that is stock jetting and would be lean with your mods. if you are not familiar with jetting a great place to start is sigma jets. dyno jet also makes a warrior kit but they are not my favorite. they have an awesome web site and all you do is plug in your machine and mods. they make a kit just for your machine with jets above and below for fine tuning. i have done a lot of jetting and i still use them because it is cheap and easy. if you dont want to use the kit go 1 up on the pilot and a 150 to start on the main. that should get you close. after that you will have to make some runs and read the plug to dial it in. ( that is why i use the kit, by the time you buy 3 or 4 plugs and a hand full of jets the kit is cheaper )
Thank you. I bought the quad as is with the mods on it. it has never ran good. I did some checking. The main and pilot are both stock sizes. Iíll go up 1 size on each and try that. (Based on the intake and exhaust mods). Iíll also check out the dynojet website. Thanks for your info.
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post #4 of 5 Old 09-09-2019, 12:34 PM
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check out the sigma as well it is a better jet kit for less money
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post #5 of 5 Old 09-10-2019, 09:04 AM Thread Starter
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Originally Posted by cory52000 View Post
check out the sigma as well it is a better jet kit for less money

I also noticed I have a "power bomb". Not sure if that will affect the jetting as well.

I'll buy the jets from the local dealer.

I'll get a 45 pilot and a 147.5 or 150 main. The needle clip is in the middle currently.
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