Forum Rules. Since '02 xBhp is different things to different people. From a close knit national community of bikers to India's only motorcycling lifestyle magazine and a place to make like minded biker friends. We have one common religion - Bikeism. Forgot your password. Remember Me? Forum Do it Yourself! Page 1 of 2 1 2 Last Jump to page: Results 1 to 10 of Last edited by Samarth ; at PM. If its a stock replacement filter You don't need to or else You need to tune the carb.
Originally Posted by kaz. Turn the idle settings screw so that rpm reaches about rpm. Please refer to the above whether you must turn the screw clockwise or anti clockwise. At the same time, ensure that the engine does not stall, by turning the idle-screw.
Tough huh? If you notice from the engine sound OR if you see the tachometer, the engine RPM will not be steady at this point. You will notice that the RPM increases slowly and steadily. Again, do this very very slowly. Also count the total number of turns as you wind out the screw. It is this point that you must stop screwing more.
This probably is the optimal setting for your engine. When this happens, you are just putting in a too rich mixture in your engine. At this point the engine loses all the fuel efficiency and the mixture is not optimal. Repeat the process about times. Count the revolutions each time and get the setting which you feel is correct. OK the engine is humming perfectly, now what? Decrease the idle setting screw to about rpm in the tachometer. When the engine slows down, just twist the throttle. The response should be crisp and quick.
It should not give any hiccups! Try shutting off the engine and restarting. The engine MUST start in a single kick or self with out giving throttle.Justin Mark started writing professionally in Small engines have a float-type carburetor and most follow the same basic design.
Tuning a small engine carburetor is easier with a little mechanical knowledge, but this is not necessary. A carburetor is a delicate and sensitive piece of equipment, so a light touch is needed to perform proper tuning and maintenance. The carburetor idle is tuned and the float bowl is cleaned during a comprehensive engine tuneup. Remove the air cleaner. Unscrew the air cleaner cover screw with the flat head screwdriver.
Pull out the air cleaner filter. Clean the air cleaner filter with an air duster. Point the air duster from inside the air cleaner to blow the dirt off the air cleaner element. Replace the air cleaner element and tighten up the air cleaner cover. Look for the fuel valve leading to the carburetor and set it to the "off" position. Locate the fuel bowl under the carburetor.
Unscrew the single screw on the base of the fuel bowl with the flat head screwdriver. Take care not to bend or misalign the float inside. The float is set to a certain level so the carburetor does not flood. Pour out the gasoline and wipe off the sediment in the fuel bowl with a rag. Also wipe the rim of the fuel bowl so that any accumulated dirt will not drop into the bowl when you put it back under the carburetor.
Replace the fuel bowl on the bottom of the carburetor. Screw the fuel bowl back into place. Do not overtighten. It should be just tight enough so that no leaks occur when the engine is started. Turn the fuel valve lever to the "on" position. Start up the engine and allow it to warm up to operating temperature. Rev the engine once in a while so carbon does not build up with extended idle. Locate the air mixture screw above the carburetor--it is the only screw facing outward above the carburetor where the air cleaner filter hose connects to the it.
Using a flat blade screwdriver, turn the air mixture screw clockwise until the engine almost dies. Turn the air mixture screw up to one whole turn clockwise or counterclockwise. What you are looking for is the smoothest idle possible. Make the turns gradually. You will have to experiment both ways to see which screw position produces the smoothest idle. Adjust the idle adjustment screw so that the engine does not die at idle speed.
You should not set a very high idle speed because this uses more fuel and decreases engine life. The engine will start faster. All adjustments to the carburetor should be made with the engine warm, using fresh fuel and the air cleaner clean and in place.
Never run an engine in an enclosed space because of the ever-present danger of carbon monoxide poisoning. Never leave a running engine unattended.Carburator Theory and Tuning. Change a jet or two and boom, your there. Yeah, right! There are quite literally millions and millions of jet combinations. A rough check on Bing carbs shows there are at least 13, different combinations of jets.
If you are going to change carbs you'd better be prepared to spend some time and money on the job. If you look at a carburetoryou will notice a rather large hole going from one side to the other. This is called a Venturi. Air passes into the engine through this hole Venturi. As the velocity of the air entering the carb and then the engine increases, it's pressure decreases, creating a low pressure or vacuum in the venturi.
This vacuum moves around in the venturi, as the throttle is opened, and sucks gasoline through the different jets in the carb.
The gas then mixes with the air going through the venturi. The way the jets are made causes the fuel to vaporize as it goes into the venturi. Where the jets are placed in the carb and where the jet's outlet is located in the venturi, determines what part of the throttle opening that jet controls.
Adjusting an SU carburettor
As you can see, the different jets over lap the operating range of each other. That is, the jet needle starts to effect things before the effect of the idle jet ends. This is something to remember when working on carbs Change one thing and it will effect other things.
OK, let's go over the different systems in the carb and see what they do. Fuel level. The fuel level is controlled by the fuel floats and the fuel float valve. The floats are hollow or made of something that will float on gasoline, such as cork. Part of the float presses against the float valve, sometimes called a needle and seat.
Most times the part of the float that touches the float valve needle is bendable so you can adjust the level of the fuel in the float bowl. All plastic floats are not adjustable. If this level is way too high, gas can leak out the carb overflow tube or into the engine. If fuel gets into the engine it will thin out the engine oil, ruining it's ability to lubricate. This will, sooner or later, blow up your engine! If a full tank of gas in the evening turns into a half tank by morning, check your oil.
If the oil is OK, check under the overflow tube. If it's OK, then check where you are parking your bike 'cuse someone is walking away with your gas! If your fuel level is just a bit high, the mixture will tend to be a bit rich.
If it's low, the mixture will tend to be a bit lean. This is because a high level takes less vacuum to suck fuel into the engine and a low level takes more vacuum to do the same.
Pilot or idle jet system. The idle jet controls the idle and on up to quarter throttle, give or take a bit.
On some carbs, like Mikuni there is an air jet too. In conjunction with the idle jet there is an idle jet air screw. This screw leans or richens the fuel mixture for a smooth idle and on up to one quarter throttle.While all modern cars use computer-controlled fuel distribution systems, there are still many vehicles on the road that employ the traditional carbureted method of fuel delivery.
Before electronically controlled fuel systems were developed, vehicles relied on mechanically operated fuel delivery systems, oftentimes in the form of carburetors to supply the engine with fuel.
While carburetors are not really considered commonplace anymore, for many decades they were the preferred method for fuel delivery, and working with them was a much more common occurrence. Although not many vehicles with carburetors remain on the road, it is imperative that the ones that do are properly tuned and adjusted to achieve optimum performance.
Carburetors can go bad for several reasons. However, adjusting the carburetor is a relatively simple job that can be done with a basic set of hand tools and a little bit of technical knowledge. This article shows you how to adjust the air fuel mixture and the idle air speed - the two most common adjustments made when tuning a carburetor.
Step 1: Remove engine air filter. Locate and remove the engine air filter and housing in order to access the carburetor. This may require the use of hand tools, however, many times the air filter and housing are secured using only a wing nut that can often be removed without using any tools.
Step 2: Adjust the air fuel mixture. Use a flat head screwdriver to adjust the air fuel mixture. Once the air filter has been removed, and the carburetor is exposed, locate the air fuel mixture adjustment screws, these are often plain, flat head screws.
Depending on the make and model of the vehicle, different carburetors may have multiple, sometimes up to four, air fuel mixture adjustment screws. These screws are responsible for controlling the amount of fuel that enters the engine, and improper adjustment will result in decreased engine performance.
Start the vehicle and allow it to warm up to operating temperature. Take note of the running condition of the engine. Use the table below to determine if the engine is running lean or rich. Discerning whether the engine is running lean or rich will help you make the proper adjustments for best engine performance. This will let you know if it is starved for fuel or is using an excessive amount.
Step 4: Re-adjust air fuel mixture screws.Forum Rules. Since '02 xBhp is different things to different people. From a close knit national community of bikers to India's only motorcycling lifestyle magazine and a place to make like minded biker friends.
We have one common religion - Bikeism. Forgot your password. Remember Me? Forum Help Me! Passion carb tuning. Results 1 to 5 of 5. Thread: Passion carb tuning. Wanted DoA.
Passion carb tuning Hello to everyone! I have a questions in my mind. On passion's carb, where is the air screw located? I was trying to tune the carb coz bike was jerking a lot, but could't find the screw.
If possible please post some pics. Only a biker knows why a dog sticks his head out of a car window.
Query Approved. Self tuning a carb for proper efficiency is very difficult. Clean the carb once. I've been meddling with my CD's air and idle screw.
Ex : if idle screw is on the left side of bike, air screw is on the right. The air screw is always coated with copper like paint. Last edited by aargee; at AM.
Similar Threads Tuning a Discover's carb. By aaron in forum Help Me! Replies: 10 Last Post:PM. Replies: 7 Last Post:PM. Replies: 29 Last Post:AM. Replies: 4 Last Post:PM. Bookmarks Bookmarks Digg del. Contact Us xBhp. The time now is AM. All rights reserved. Runs best on HiVelocity Hosting. Connect with us on xBhp Connect. Our Partners.Forum Rules.
Since '02 xBhp is different things to different people. From a close knit national community of bikers to India's only motorcycling lifestyle magazine and a place to make like minded biker friends.
We have one common religion - Bikeism. Forgot your password. Remember Me? Forum Help Me! My pulsar tuning gone bad. Page 1 of 4 1 2 3 4 Last Jump to page: Results 1 to 10 of Thread: My pulsar tuning gone bad.
My pulsar tuning gone bad Dear onesIm not a techie in bike but I understand my bikes performance. Im a new user to this forum but I used to read the threads. Mine is DTS I ug3 blue pulsar. This is my first bike. I love it very much and I used maintain it very well. Every 2. Every 6 months once I change the brake shoes Every 3 months once i. In BP petrol pump I put the speed petrol for rs that time the speed petrol price is rs My bike was in reserve mode only I saw it is running more than km so I dont want to take risk so I have put petrol.
After that I sticked with normal petrol.Note: If your engine does not start or idle properly now, you should attempt determine the cause and repair it prior to making these carburetor modifications.
How to Tune and Adjust Your Carburetor
Do not under-estimate the ability of the stock Keihin CV carburetor to produce good horsepower. The stock CV carburetor has a venturi diameter of 40mm 1. A stock bike cc 80 CID can develop up to 64 horse power with a well tuned and modified CV carburetor. Click here to see dyno testing on the CV against other carburetors. With a few parts from your local Harley-Davidson Dealer and some tools, you can re-jet a CV carburetor and improve the performance of your bike.
Slide Spring 2. Slide Diaphragm 3.
How to Tune a Small Engine Carburetor
Vacuum Slide 4. Vacuum Port 5. Needle Jet 6. Main Air Jet 7. Main Jet 8. Slow Jet 9.Inside A Motorcycle Carburetor - Needle Height Tuning Adjustment - MC Garage
Idle Mixture Adjustment Screw Throttle Plate Step 1. You might get away with leaving the throttle cables connected. It is much easier to remove the carburetor and use a work bench. It is faster to cut the fuel line hose off rather than trying to save it. If you take out the rear fuel tank bolts and loosen the front bolts, the fuel tank can be raised a few inches. The extra room gained by raising the tank is the difference between struggling with the job and making it easy.
The aluminum plug covering the idle mixture adjusting screw needs to be removed.