Pilot Air/Fuel Screw Adjustment Explained - Single Carb - Part 1

A carburetor backfire describes the small explosion that sometimes occurs when starting up a car. It generally makes a loud sound, like a gunshot, and occasionally is accompanied by a visible flame. Generally, a backfire is caused by an imbalance in the air to fuel ratio. Either the engine is not getting enough fuel, which is also called running lean, or the engine is getting too much fuel, which is also called running rich.

Yamaha kodiak 400 backfires through carb

There are a few different issues that can create this situation. If your engine is not timed correctly, it may backfire. If your car has an ignition distributor, adjusting it may be able to correct a timing issue. Otherwise, the timing of the engine will need to be adjusted with a timing light.

A faulty fuel pump, or a clogged fuel filter, is another possible cause of a backfire. Your fuel filter should be changed regularly.

A faulty fuel pump is a much bigger issue. If your fuel pump is failing, it will need to be replaced immediately. If your vehicle is equipped with a fuel injection system, make sure that it is cleaned and maintained regularly.

A clogged fuel injection system will not burn fuel completely and can cause backfires. A leak in the injection system, usually the result of a stuck air intake valve, is another common source of backfires. Using fuel injector cleaner might take care of the problem. If not, you will need to replace the faulty injector. This article was written by the It Still Works team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.

To submit your questions or ideas, or to simply learn more about It Still Works, contact us. Why Does My Carburetor Backfire? Fuel Pump and Fuel Filter A faulty fuel pump, or a clogged fuel filter, is another possible cause of a backfire. Fuel Injection System If your vehicle is equipped with a fuel injection system, make sure that it is cleaned and maintained regularly. Stuck Valve A leak in the injection system, usually the result of a stuck air intake valve, is another common source of backfires.

About the Author This article was written by the It Still Works team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.The oil capacity for the Yamaha Big Bear is 3. It is recommended you use 10w30 oil in the Big Bear. Mrs Smith has nine children half of them are girls.

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Wiki User Loose intake boot or the boot may not be on straight. Happens everytime.

yamaha kodiak 400 backfires through carb

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yamaha kodiak 400 backfires through carb

Community Guidelines.I have a 06 raptor and recently i added a jet kit and a pipe. Since then my carb has been sounding like it is backfiring. It is jetted like it said and the fuel mixture screw is 3 turns out like the instructions say. I've cleaned it out and put fresh gas back in and Changed the spark plug but still the problem persist, What is causing this?

Jetting reffers to throttle position and not RPMs so speed is not a factor. Heres what you need to do Lean means less gas, rich means more gas.

Again smaller is leaner, larger is richer. When jetting your carb if you find that you need to turn the pilot jet all the way in to improve response then you likely need to switch to a smaller number of screw.

If on the other hand you need to turn it more than 2. Now that you understand the why turn the screw IN to lean out the mixture a little bit. Don't turn it in too far, a lean condition over a period of time causes engine damage. Turn it in half a turn at time and test for results. The book probably says that to keep your engine safe since being too lean causes engine damage while too rich usually just makes the engine shut down.

Hope that helps. Sometimes drilling a few 1" holes in the airbox cover will increase air flow and improve running. The mixture is running too rich. Clean the carb. That will dissolve all varnish and gum. You mentioned he lapped the valves, but it sounds like the intake valve is not seating properly.

This would cause it to backfire through the carb. Have him replace the intake valve and spring and you will probably be good to go. Hope this helps and good luck. Trending News. CDC adds new signs to list of virus symptoms. Naya Rivera's selfless last act: Saving her son's life. States extend unemployment while Congress debates. Photo of Ted Cruz on a plane with no mask goes viral.

Inside Lisa Marie Presley's close bond with late son, All eyes are on Disney World following its reopening. Hosting shakeup on 'Dancing With the Stars'. Trump turns focus to Obama after coronavirus question. Answer Save. Travel Gal. It sounds like you're describing a rich condition so onto 2 2 - Every jet is identified by a number and that number relates directly to the size of the opening inside the jet.

This Site Might Help You. RE: Atv is backfiring through carb.? There was a recall on earlier Raptors. They would back fire and blow the carbs off the manifolds.Registration is fast and you can even login with social network accounts to sync your profiles and content. I have a couple of questions again please. In cleaning the carb i took the needle valve out I need to know for sure how these go back because they fell out of the carb when i took the needle valve out and I am not unsure of how they go back in I think the spring first slides onto the needle valve, but what comes next if so the washer or the rubber O ring?

Next I noticed the breather that i purchased does not set tightly into the hose that comes out of the carb would that keep it from idleing correctly? Thank you in advance. I called it a needle valve cause of not knowing much about atv's. I think its called a Idler anyways its not in the bowl where the float is at. I took it out to clean it and a small washer and 0-ring fell out before i could tell which one came out first So if anyone could help me I would appreciate it I think its the 0-ring that goes in first and then the spring and then the washer goes on the idler jet?

If someone that knows about these things would reply I sure would appreciate it Thank you. What you took out is the mixture screw.

Put spring on mixture screw, then washer, then O-ring. Holding the screw so that those parts don't fall off, insert it into hole. I hold the carb so I can insert the screw with tip up, that way the parts wont fall off. Make sure you lightly seat the needle valve and then back it out the same amount of turns it was originally. If you don't know what that adjustment was, you will have to find out. Good Luck.

I am trying to figure out how to "seat" this "pilot screw" outside of the float bowl before backing it out 2. This "pilot screw" can be screwed in so far that the tip can actually be seen coming through the hole in the bottom wall of the carburetor exit.

Why Does My ATV Engine Pop When I Give It Throttle?

And no, I am not talking about the "jet needle". There is also a "pilot air jet" set screw on the left wall of the intake side of the carburetor. That needs to be adjusted correctly too. I have read posts that it should be 2 turns out from a soft seat. That screw has a definite seat.Join us now! Forgot Your Password? Forgot your Username? Haven't received registration validation E-mail? User Control Panel Log out.

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Essentials Only Full Version. Mud Master. Yamaha Kodiak carb adjustment Does anyone know how many turns out the pilot jet should be? I cleaned my carb and forgot to check. Now it idles way too high. This is on a Yamaha Kodiak It's a Mukuni BSR Is the pilot screw part 14 or part 18? Should part 14, Pilot Jet, be turned out about 2 turns?

Should the Pilot Jet be fully seated and all adjustments made with part 18, Pilot air jet. I have never moved part 18 but had part 14 out. Part 14 is inside the carb bowl, part 18 is outside the carb facing the air box. Mud Pro. The pilot jet is inside the carburetor. Most of the time you can turn them out about 2 turns or so and they are fine.

yamaha kodiak 400 backfires through carb

PART 2 is what controls your idle. You should turn it counterclockwise to decrease the idle of the bike. Thanks I've got it now.

It was working fine until I drowned it.JavaScript seems to be disabled in your browser. You must have JavaScript enabled in your browser to utilize the functionality of this website.

General : Don't need to ride with the choke opened. Super fast shipping!!! Got it in 2 days, Florida to me in Colorado. What a difference. If you are having trouble with your carb and cleaning doesn't help. Come here and buy a new carb. Especially if you bought a used bike. I finally gave up on my supposedly rebuilt carb, bit the bullet and bought this Genuine Mikuni, bolted it on and haven't had to adjust anything but the idle speed. Now if I have to rebuild in the distant future I'm at least starting with an "unmessed with" carb.

Who knows what the prior owner did to the original carb.???? This carburetor bolted right on and my Yamaha Big Bear and started right up. It runs great now. Original Mikuni is the way to go.

Got it with in 2 day's put it on my kodiak hit the starter and it fired right up, throttles out good no adjusting to it. Thank's guy's. Ive bought 3 carbs for my atv and had nothing but problems.

Bought this one installed and cranked right up and ran perfect. Thank you so much. This carb came from MIkuni with the fitment specified as only for the Kodiak models. If the part numbers are the same, then this carb will work for you. Unfortunately, this carburetor is not correct for your year or model Kodiac FW Ultramatic. We do not list your Kodiak in our fitment guide, which is provided by Mikuni. I checked our stock and we also do not carry a replacement carburetor or rebuild kit for the carburetor for your Kodiak.

There is a brass emission control seal cap over the space where the screw should be located and you'd have remove that cap to adjust the screw. I cannot confirm there is a screw in this space, however, because I would not be able to sell the carb once I removed the cap.

It is conceivable that Mikuni could make this a permanent adjustment as well. The Yamaha part number is 5TE-E This is not the correct carb for the Kodiak models. The carbs for the and appear to be identical. However, I compared the OE part numbers for the and Kodiak models. The beginning of the part number is slightly different for these models, so I cannot confirm this carb will fit.

There may be a very minor difference that would not be noticeable, or it may be a more significant difference that may effect performance.Why does my ATV engine pop when I give it throttle? Here is exactly what reader Jayson asked the Answerman it is long and extremely detailedfollowed by his answer:.

I have a arctic cat manual shift. The problem, The machine will start fine and idle like it should, once you get into the throttle it will start to misfire and back pop but will not die even if you hold the throttle, it just pops.

Last summer I began to have battery charging issues, my dad, who was the original owner of the bike, came over we started looking into fuses and wiring connectors and YouTubed the symptoms.

The battery began charging correctly and everything seemed to run fine, appropriate voltage back and such. I then put the carb back on after a thorough cleaning and installing a inline filter and had the same problem. I figured quite a long shot but what the hell. I put the meter back on it and I was getting almost seventeen volts back, which was not the case when we first installed it. With the headlights on it drew down to almost perfect voltage, After three or four times of riding it it has begun to run like garbage again.

Backfiring and popping and dying and it would only start and run with the choke halfway on. Today I cleaned the carb and once again it was still very clean inside. I put it together checked the voltage at an idle with the lights off and was getting a good reading and ran it around the yard a little and it began to misfire and pop I pulled it in checked the volts again and was back up around seventeen, lights on it dropped to Have you heard of anything like this?

Should I just tear into the flywheel and stator and see what I find? I really want to repair it and put it back to work. Holy Moly, Batman, this is the longest question and the most detailed I have ever received.

I love it! That is what forums and the World Wide Web is about. Sharing is caring. Now some information can be misleading, but sifting through the core of it you can find the most common issues pretty quickly. With that said, lets try a few things to see if it helps the problem become better or worse. My very first thought is that the engine is not getting enough fuel.

The popping is most typically a result of a lean running condition.

Atv is backfiring through carb.?

Have you pulled the plug after a good warm up to see what it looks like? While some will argue you need to ride a few minutes and then pull the plug, we know by your comments that the machine will not run without popping or backfiring. So warm it up and place your hand over the snorkel opening to the air box to temporarily close off the opening. That is the shark fin looking thing on the front of the air box lid.

As the engine is running and you have your hand cupped over the opening, press the throttle to see if the popping gets worse, quits or smoothes the engine out. By choking the engine this way you introduce more fuel to the cylinder. The result tells us to either move on or stop and check the fine inlets for the primary fuel meter circuit.

Trust me when I say that I know how clean a carburetor looks after going into it 10 times and it still will not smooth out for you.