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ATV Carburetor Adjustment involves tuning your ATV’s carb for maximum performance.
How do I know my jetting is off? My ATV bogs down a lot, is jetting to blame? I have performance parts, what now? These are all common questions so lets get you up to speed on ATV carburetor adjustment.
You can tune your own ATV jets and avoid common jetting mistakes if you understand some jetting basics, explained below. A comprehensive installation guide will come with the jetting kit you purchase for your make and model of ATV so instead this guide will focus on explaining the basic principles of how ATV jets work. How jetting works…
#1 – The first thing you need to remember is that ATV jetting refers to throttle position, not engine rpm. Each jet is effective for a specific throttle position range. The pilot jet, or pilot screw as it is sometimes referred to, controls the flow of fuel between Idle speed and about one eight of wide open throttle (WOT). The needle jet controls the flow of fuel from the one eight position up to about the three quarter throttle position.
Lastly your main jet controls the flow of fuel between the three quarter and wide open throttle positions.
#2 – The second thing you need to know is that aftermarket performance parts will change your jetting requirements. Increased engine performance usually means an increased demand for fuel so learning ATV carburetor adjustment techniques is important.
Other factors that affect jetting are rev limiters, altitude and fouled plugs if your jetting is off. Altitude directly affects engine performance because the higher you go from sea level the thinner the air gets.
The pilot jet, also referred to as pilot screw, controls carburetor fuel/air mixture between Idle and 1/4 throttle. Turning the screw IN makes the fuel/air mixture leaner. Turning the screw OUT makes the fuel/air mixture richer. Lean means less gas, rich means more gas.
Every jet is identified by a number and that number relates directly to the size of the opening inside the jet.
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 2.5 turns out you likely need a larger numbered screw. When your engine bogs down at the smallest increase in throttle position your pilot jetting is likely too rich.
The needle jet and its needle controls the fuel/air mixture from the 1/8th throttle position all the way up to the 3/4 throttle position. The needle within the needle jet is a long tapered pin. As you increase the throttle position the pin pulls out of its jet allowing the fuel/air mixture to become richer. There are several different shapes and diameter of needles/needle jets but the needle jet is often left alone during tuning as it doesn’t affect idle or top end performance. The same rich/lean characteristics apply as with the pilot screw.
The main jet controls the fuel/air mixture from 3/4 throttle position up to wide open throttle. Again the main jet is numbered and a larger number indicates a larger hole and a richer mixture. A stock engine will perform well with a stock main jet but once engine performance parts are added its likely that you will need to revisit at least the main jet of your carburetor. Different performance part combinations will create different demands from your carburetor. Anything that increases horsepower will also increase fuel demand.
All the performance parts in the world won’t improve performance if you don’t tune your carb. If you have a rev limiter in place you may need to tune or upgrade that as well because a rev limiter will tend to bog down the engine at full throttle. Make sure to follow the instructions included with most jetting kits.
Now that you, hopefully, understand a bit more about the basics of how ATV carburetor parts work these are the steps to take if you’re in a jam on the trails.
Blockage, damage, fuel contamination, mud in the air intake system and other conditions can cause your ATV carburetor to be unable to deliver the right amount of fuel to your ATV engine. You always want to tune your ATV carburetor at home or in the shop but that’s not always possible. If you’re in a jam, this is what you can do.
This is not attaching the carburetor to the engine, it’s going to turn freely if you adjust it.
You can continue to adjust it a bit until the engine sounds better and runs without hesitation. If you turn it too much you will eventually flood the engine with too much fuel and this will make it bog down and be hard to start as well. A flooded condition will require time for the fuel to evaporate.
Carburetor jets control the amount of fuel which is mixed with air inside the throttle body of your carburetor. This carburetor jet size chart shows you how effective each jet is at specific throttle levels. A Pilot jet is effective at idle speed up to 1/4 throttle(low-range). A needle jet is effective from 1/4 throttle to 3/4 throttle(mid-range). A main jet is effective from 3/4 throttle up to wide open throttle(top-end).
When diagnosing a carburetor or tuning problem look at the jet responsible for the range in which the problem is occurring.
ALWAYS follow the manufacturer’s specifications whenever possible. Jet size is usually stamped onto the jet itself, typically in milimeters(mm), ranging from small to large. Changing a carb jet for a smaller sized jet will reduce fuel flow. Likewise, installing a larger jet will increase fuel flow and may help a performance engine run more smoothly. Note: an engine that runs rich is less likely to sustain heat damage than and engine that runs lean.
I hope that this carburetor tuning guide helps you understand how jets work so that you can best dial in your ATV for maximum performance(and fun!).
Note: compressed air is extremely helpful in clearing obstructions.Carburetor jets become clogged naturally over time and a periodic carburetor cleaning is required. Always consult with your ATV owner’s manual for specific maintenance instructions. Always check the fuel lines, filter and gas tank for contaminants and clean as required at the same time to avoid further clogging.
The majority of carburetor problems are a result of blockage and worn out parts. Troubleshooting a clean ATV carburetor is also much easier than troubleshooting a dirty carb.
Typical tools required include a flat head screw-driver, compressed air, an 8mm wrench and carburetor cleaner. Note: Some gaskets and plastic components will swell if exposed to carb cleaner so remove these prior to use.
ATV is most often used for driving on difficult terrain. On the way riders encounter mud, potholes, sharp climbs and deep fords. Loss of concentration or inattention can lead to the most deplorable consequences. For example, to drowning an ATV.
Before crossing the ford, it is imperative to check its depth. However, this very ford is often deceptive. In one place it seems shallow, but if you deviate just a meter to the right or left, you dive headlong into the water. Most often, this is how the ATV is drowned. nine0003
What to do if you drowned the ATV? We will tell you about some activities that will help resuscitate your car. Note that if you do not respond promptly, you can get an engine water hammer.
So, the ATV is out of the water. Let's move on to saving our patient. Never try to start the car. It is better to deliver the ATV to the garage on a trailer.
Open the lid, drain the water and dry. Then we lubricate everything with oil and install the filter in place. nine0003
Thoroughly clean the carburetor and blow out the passages. For flushing, you can use pure gasoline or specialized fluids.
Pour out all the gasoline from the tank, rinse everything with clean gasoline, change the fuel filter.
Unscrew and drain the water. Then the pipe must be cleaned and dried. nine0003
Wire connections are the most exposed to water. We separate them and pour them with silicone grease.
Open the lid and drain the water. We clean the plates and dry the belt.
Let's move on to the most difficult part. You need to determine if water has entered the engine. To do this, check the oil dipstick. If water does get to the engine, the oil will react and form an emulsion. nine0003
If the worst assumptions come true, immediately drain the oil and flush the engine. Change spark plugs and oil filter.
For the next step, you will need an M8 motor mineral water. Pour it into the engine and scroll the starter. Please note that this must be done without a candle.
After that, install the candles and start the engine. We let the engine run for a couple of minutes and turn it off. Then drain the oil and repeat the procedure 6-7 times.
We change the oil and load the gearboxes.
After that, it is better to drain the oil and pour new.
These items must be syringed.
Well, this is the simplest. Just dry the seat.
After rescuing the quad, carefully inspect the machine again and remove all traces of moisture.
If you do all these 10 points quickly, your ATV will be saved. In any case, after that it is better to contact the service center. nine0003
Be careful not to drown your ATV!
ATV engine ATVs 4x4
10.03 at 10:32
TK-RAS (carrier):
???
10.03 at 10:30
TK-RAS (carrier):
Is your order still valid?
10.03 at 10:29
TK-RAS (carrier):
Alexander is ready to load tomorrow
10.03 at 10:29
TK-RAS (carrier):
Good afternoon!
09.03 at 13:19
Alexander (customer):
OK
09.03 at 12:28
TK-RAS (carrier):
I will clarify everything and write to you nine0003
09.
03 at 12:28
TK-RAS (carrier):
Good afternoon!
09.03 at 11:15
Alexander (customer):
ATV size 2.36x1.20x1.50 weight 400 kg
09.03 at 11:14
Alexander (customer):
Ask for price
09.03 at 11:14
Alexander (customer):
Good afternoon. You will only need to carry an ATV without a trailer from Ust-Luga, Leningrad Region, to the village of Starominskaya, Krasnodar Territory. Date care March 11 at 11:00 nine0003
07.03 at 21:01
Alexander (customer):
Understood. Good
07.03 at 21:01
TK-RAS (carrier):
Not a very convenient download location
07.
03 at 21:01
TK-RAS (carrier):
9.03 write to me and I will look at the car
07.03 at 21:00
TK-RAS (carrier):
I can't tell you the price right now. nine0003
07.03 at 20:55
Alexander (customer):
March 11th
07.03 at 20:55
TK-RAS (carrier):
What numbers do you need to load?
07.03 at 20:53
TK-RAS (carrier):
Now I will clarify
07.03 at 20:53
TK-RAS (carrier):
5800r make a reservation and I will immediately put you on the schedule nine0003
07.03 at 20:53
Alexander (customer):
The ferry turns out to come not to St. Petersburg, but to Ust-Luga. How much will the shipping cost change?
07.03 at 20:53
TK-RAS (carrier):
In order to order transport, you need to click on the button “BOOK BY PRICE”. Next, the system will ask you to make a reservation. Reservation is a guarantee of the price and conditions for the execution of your order. By paying a small part of the cost of the order, you thereby confirm your intentions for transportation, which allows the contractor to plan their schedule taking into account your load! After paying for the reservation, you will automatically receive all the contacts of the carrier. nine0003
07.03 at 20:52
TK-RAS (carrier):
Payment takes place in 3 stages 1) Reservation of transport 2) Prepayment to the card of the Security Council of the Russian Federation after signing the contract 3) Cash balance on unloading.
07.03 at 20:52
TK-RAS (carrier):
We draw up a contract from IP for transportation
07.03 at 20:52
TK-RAS (carrier):
We accept orders in advance. Everything needs to be planned well. At the last moment, prices sometimes rise here, for urgency. I want to warn you not to get into this situation. nine0003
07.03 at 20:52
TK-RAS (carrier):
I will do everything honestly, you will be satisfied
07.03 at 20:51
TK-RAS (carrier):
We ourselves are from the Krasnodar Territory, since I will help my fellow countryman
07.03 at 20:51
TK-RAS (carrier):
The day before loading I will know for sure and we will send you a contract, we will indicate everything there
07. 03 at 20:50 nine0003
TK-RAS (carrier):
There is a car from a gazelle to a truck
07.03 at 20:50
TK-RAS (carrier):
Alexander machines are different all the time in the work do not stand still
07.03 at 20:24
Alexander (customer):
Please tell me what kind of car you plan to transport?
07.03 at 18:02
TK-RAS (carrier):
We accept orders in advance. Everything needs to be planned well. At the last moment, prices sometimes rise here, for urgency. I want to warn you not to get into this situation.
07.03 at 18:02
TK-RAS (carrier):
There is a solution?
07.03 at 15:31
Alexander (customer):
OK
07.
03 at 15:20
TK-RAS (carrier):
I'm waiting for your answer nine0003
07.03 at 15:19
Alexander (customer):
I'm looking for loading options
07.03 at 15:17
TK-RAS (carrier):
Alexander are you here?
07.03 at 15:04
TK-RAS (carrier):
Are you ready to negotiate?
07.03 at 15:04
TK-RAS (carrier):
We carry different equipment all the time
07.03 at 15:03
TK-RAS (carrier):
If not, then you need something to load into the body. Lots of options
07.03 at 15:03
TK-RAS (carrier):
If you find a ramp, the car will drive up backwards and you will drive in
07.
03 at 15:02
TK-RAS (carrier):
Fix in the body
07.03 at 15:02
TK-RAS (carrier):
So the load will take up less space along the length
07.03 at 15:02
TK-RAS (carrier):
And put the trailer next to the edge
07.03 at 15:01
TK-RAS (carrier):
The quadric from the ramp can be rolled up either by a tow truck or a manipulator
07.03 at 15:00
Alexander (customer):
I have a question about loading and unloading nine0003
06.03 at 18:43
TK-RAS (carrier):
And which one will do?
06.03 at 18:42
Alexander (customer):
No, I don't like this option.
06.03 at 18:36
TK-RAS (carrier):
Are you ready to negotiate?
06.03 at 18:35
TK-RAS (carrier):
Your loading and unloading nine0003
06.03 at 18:35
TK-RAS (carrier):
Alexander we ourselves are from the Krasnodar Territory, I will be glad to help
06.03 at 18:34
TK-RAS (carrier):
Hello, Dear Customer! *** WE WORK WITH "LUCK EVERYONE" FOR MORE THAN 8 YEARS. MORE THAN 2,700 TRANSPORTATIONS HAVE BEEN CARRIED OUT.*** WE WORK CONSTANTLY ON YOUR ROUTE***.Official transportation at any time convenient for you***.Contract guaranteeing the safety of the cargo and providing the car.*** If necessary, we will provide loaders in two cities*** .The machines are all in good condition: dry and clean body, there are belts and fasteners***.
The needle jet is seldom changed in everyday tuning, but it's still worth mentioning the fact that it's there. The needle itself is a basically a tapered rod connected to the throttle slide. As the slide opens the needle is pulled upwards. The needle is tapered so that as it's pulled up, it takes up less space in the needle jet. This allows the fuel flow to be gradually increased as the throttle is opened. The needle has a clip that allows it to be lowered or raised in relation to the carb slide, which gives an overall richer or leaner setting. Raising the clip up a notch drops the needle down farther, causing a leaner mixture. Lowering the clip raises the needle up, causing a richer mixture. You can also get different diameters, and tapers of needles. If the clip is lowered all the way, and the mixture is still lean, you need the next size smaller needle. If the clip is raised all the way, and the mixture is still rich, you need the next size larger needle.
The pilot jet is similar
in design to the main jet, basically a small screw with a
calibrated hole in it. As with main jets they are identified
by number, a larger number pilot jet is richer, and a smaller
number pilot jet is leaner. The pilot screw on an ATV regulates
fuel flow.. Turning the screw in makes the mixture leaner,
and turning it out makes it richer. If the pilot screw winds
up being turned almost all the way in, you need the next size
smaller pilot jet. If the pilot screw is more than about 2
1/2 turns out, you need the next size larger pilot jet. Basically
the pilot screw is an adjustemnt that allows you to fine tune
the pilot circuit.
