This article will explain the difference between rich and lean, as well as how to tell how your dirt bike is running. This works for 2 stroke and 4 stroke bikes. What Does Running Rich vs Lean Mean? Running rich vs lean is regarding how the carburetor or fueling system is controlling the air and fuel supply 2 Stroke 50cc + Engine and Transmission. I'm just wondering if there is a clear cut way to diagnose whether an engine is running too lean or too rich? On my Milan I had the same problem you are having with the sluggish pickup and and popping sound. It was running too lean. Try messing with the mixture screw 2 Stroke Carburetor adjustment procedure for off-road motorcycles (it should still sound very slightly rich but it should respond and clean out instantly If the clip position is too lean the engine will sound quiet and have a dead feeling possibly hesitating. A needle that is set in a clip position that is too lean will also cause.
Rich= high gas/air ratio (not enough air), lean = low gas/air ratio (too much air). A bike jetted too lean will bog, detonate (ping), and no spooge will come out the exhaust, it also may overheat and spit coolant. A bike jetted too rich will sound blubbery, have excessive spooge, somewhat sluggish response, and will run cooler and potentially.
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Good running conditions: If everything is good, the spark plug should have a tan/light brown color. Rich running conditions: If your engine is running too rich, the spark plug will be black and sooty. Lean running conditions: If your engine is running too lean, the spark plug will be white. If the spark plug is black and oily, they are oil fouled It does not have the same normal 2 stroke ping as other bikes, it's a lot deeper. And when I'm on the throttle, about 1/4 and below (idle jet) it is always sounding very deep and poppy, any other throttle range it sounds like a normal 2 stroke. Does my idle sound rich or lean or ok? FMF fatty & FMF silence
2 Stroke 50cc + Engine and Transmission. I confirmed that a sound i have been hearing (started about 1.5 weeks ago) is a backfire. (sounds like running over a flattened aluminum can) so would this be a lean or rich condition? 2008 Roketa MC-54 - 10000 miles MC-54 Parts Cross reference list . motomech Great Big Guru Dawg You need to get the engine up to operating temp or it will cause excess ware on the piston. I need to vary from 4-cycling to 2-cycling at full throttle every 10 seconds. Vary from 300 rpms rich from peak rpms to just before it 4 strokes. I know the newer OS engines are made less tight but I still wouldn't 4 stroke it I have heard many people say lean until it's rough and then just rich enough to smooth it out. This leads me to a question. When I lean my engine on the ground this is what it looks like in order as I bring the mixture back: 1. engine rpm increases 2. RPM maxes. At throttle back all the way engine rpm will be up around 950-1000 RPM 3 Rich's post are always good, check his history. 2Strokerfun, sorry but that just doesn't work on a thumper. cthowards did a good job of describing the process. You just need the idle a little higher than normal so the bike won't die when you go in/lean. Going out gets rich and sounds flat if you go to far 11-12-2011, 10:46 PM. I've always held the logic that generally the higher octane rating the better for either a 2 stroke or a 4 stroke. So 95 over 91, and 98 when you can get it. Obviously an engine which runs more advance, higher compression or both will demand this, however I have read some stuff recently which suggests some bikes.
The opposite of the too rich setting is the too lean setting. This means there is too much air in the mixture which causes the explosion within the cylinder getting too hot. Whilst the engine usually performs very well in cold state, it often stops suddenly after a few minutes of riding and only turns on again after it cooled down In a two-stroke engine, the combustion cycle is completed in two strokes of the piston. It is a good practice to listen to your engine sound to judge the correctness of screw adjustment. Also, the reasons for the above troubleshooting can be: Carburetor out of adjustment resulting in a rich or lean air-gasoline mixture
lean-burn, 4-stroke lean-burn, and 4-stroke rich-burn. Two-stroke engines complete the power cycle in a. 3.2-2 EMISSION FACTORS 7/00 single crankshaft revolution as compared to the two crankshaft revolutions required for 4-stroke engines. All engines in these categories are spark-ignited Believe it or not, on a 2 stroke, the mixture also contributes to cooling the piston. Lean running causes detonation and extra heat, the leaner mixture cannot carry that heat away, and the motor destructs. But, at idle, you never really generate enough heat for this to be a problem. I agree, the motor will die at idle if too lean 2 Stroke naturally aspirated Target AFR/EGT AFR = 12:0-12.6:1 EGT = 1100-1200F 4 Stroke naturally aspirated target AFR AFR = 12.8-13.4:1 4 Stroke Boosted target AFR The more Cylinder Pressure the lower the number! The lower the Octane the Lower the number! AFR = 10.9-12.5:1 Where to install EGT bungs 2 stroke exhaust When should I use a 2-stroke engine vs a 4-stroke? After two tanks of fuel have been run through rich I lean it up and it runs great the rest of the night. What could be wrong? My large two-stroke engine makes a knocking sound at medium to low throttle settings. Large-bore engines, usually larger than .91 or so, tend to have a.
Similar Threads for: New to 2-stroke sounds: Thread: Thread Starter: Forum: Replies: Last Post: form on 2 stroke vs 4 stroke trail bike: mxmama393: Dirt Bike Riding Tips: 39: 03-20-2010 12:44 PM: Wanted 90's to early 00's 125 2-stroke or 250 4-stroke: littlebeep3: Classified Ads: 3: 08-08-2008 01:11 PM: haha, sounds of 2026 suzuyamah YM250. Then we adjust it lean causing it to sound smoother and then it starts to starve, also creating little power and creating a LOT of heat. As we back it off from lean to rich again, the sound becomes slightly rougher. This slightly rough sound (or 4-cycle sound, as it's sometimes referred to) is where you want it to be The sizes (rich to lean) are .5, 1.0, 1.5, 2.0, . Since it covers the same range as the main jet, it is often ignored, and in very many cases it is removed all together. The air-jet has it's greatest effect in carb setups that are running (long hex) main jets in the 400+ range
The one thing you want to avoid is going too lean (especially at high RPM) because a lean fuel mixture is a prescription for detonation, preignition and burned pistons. Advertisement If the engine is on a test stand (not a dyno) or in a vehicle, you can use a handheld A/F meter with a wideband O2 sensor to measure the A/F ratio in the exhaust It's a 5:1 movement ratio. CV: If the float sticks out further, down, into the float bowl, the carb will deliver less fuel (leaner), especially at low rpms and at cruise. Slide carbs: Float height controls 25% throttle at all rpm's, even at redline. You'd generally change the float height in 1mm increments when tuning Engine Basics: Detonation and Pre-Ignition. All high output engines are prone to destructive tendencies as a result of over boost, misfueling, mis-tuning and inadequate cooling. The engine community pushes ever nearer to the limits of power output. As they often learn cylinder chamber combustion processes can quickly gravitate to engine failure When an engine runs lean, there is an imbalance in the air/fuel mixture. Particularly in two-stroke engines, the term refers to the engine not receiving enough gasoline compared to the amount of oxygen used in the combustion process. Very little gasoline is required for combustion, but enough is needed to keep piston chambers cool while operating The sound occurs when unburnt fuel exits the cylinder and is pushed out during the exhaust stroke before being ignited by the spark of the next cylinder, causing it to explode out through the exhaust system. You can also tell that you likely have an engine misfire if it sounds like your car is struggling
The soot on this spark plug indicates a rich air-fuel mixture. An easy way to tell if your engine is running lean is to look at your spark plugs. If your spark plugs are clean and white after being ran in your engine, the air-fuel mixture is lean. 4. Reduce Gas Mileage. A lot of these symptoms go hand in hand This occurs commonly when the engine is running rich, running lean or has an exhaust leak. The sound of a backfire can be startling to the unexpected ear and worrisome or annoying to the motorcycle owner. A backfire is an explosion that happens within the intake or the exhaust of your motorcycle. This explosion is meant to take place in the. . When the main jet is Rich the engine will be a bit flat or lazy at ¾ to full throttle, giving off a flat, dead sounding exhaust note. When the main jet is severely rich the engine will sputter in the high RPMs and have a lot of trouble making power up top Make a note of the position of the screwdriver slot and compare it to the position of the lean adjustment. Now slowly turn in the screw to a position where it idles the best. It should be about midway between the rich and lean positions. Click on the link below and a WAV sound clip will be loaded into your browser. What you'll hear is an idling. A faulty MAF sensor is the most common cause of an engine that is running rich.. The MAF sensor calculates the air, which is going into the engine, and then calculating the air-fuel mixture that should be added. If this is dirty or failed, it will cause the engine to run too rich or too lean
The burning fuel expanding forces the piston downward. At this time the valves are closed. This is the power stroke. As the crankshaft turns, the piston begins to go back up and the camshaft opens the exhaust valve. The upward moving piston forces the burnt gases out of the cylinder. This is the second or exhaust stroke Alternatively you can take a 3/4 outside diameter washer and weld it to the top of a 3/4 x 1/4 bolt. STEP 2: Drill a 1/4 hole about 1 inside your head pipe where your aftermarket exhaust slip on. STEP 3: Take the tunable baffle and place a 1/4 nut and a lock washer (away from the large washer). Now insert your tunable baffle into the.
Troubleshooting Rich Condition: 1. The engine runs on rich mixture does not have the smooth and crisp acceleration, in fact the acceleration tends to be flat and uneven. The engine looses the smoothness. 2. The engine idle becomes rough and pulsating; you need to blip the throttle to get it back to the idle. 3 Best Ethanol Fuel Treatment Reviews. 1. STA-BIL 22240 Marine Ethanol Treatment. STA-BIL 360 is a top boat fuel treatment because it anticipates the average boater's habits and addresses plenty of ethanol problems at the same time. Despite its obvious strengths, I can't back the brand's claim that it makes fuel last up to a year A normal healthy idle air control valve (IAC) will provide smooth idling in your vehicle. But if the valve goes bad for any reason, the idling will go from smooth to rough. A rough idle will result in intense vibrations forming whenever your vehicle is stopped with the engine running. Since less air will be going into the engine during its idle.
A banging sound can be heard as the bike backfires. You can tell if the air/fuel mixture is too rich if there is a potent gasoline smell when the bike is idle or if the engine is running unevenly. If your engine is running lean, there is more air in the combustion chamber, and your engine is starved of fuel. The fuel will pass into the exhaust. 4. Make adjustments 1/2 a turn in either direction to find the smoothest idle speed. Turn the screw counterclockwise and clockwise 1/2 a turn from the middle position and listen to the sound of the idle. Set the screw in the position where the engine's idle sounds most even and smooth to balance the fuel mixture Typical symptoms of a lean mixture are: Backfiring as the throttle is closed (primarily during coast-downs) Lurching acceleration. White or light gray spark plugs. Requiring excessive amounts of choke to run/start. White or light gray muffler end pipes. Bluing (on chrome systems) of the exhaust header down-pipes Damaged vacuum lines will also make the bike running lean. These are easy to visually inspect, as well as fast and cheap to replace. Reason 2: Dirty, damaged or poorly adjusted exhaust valves. The exhaust valves inside your engine have the important job of closing when ignition happens, then opening to let the exhaust gasses out on the next stroke . A healthy heart is key for a healthy life. The same is true for engines, except their heart is a carburetor. Just like cholesterol in the heart, if dirt and gummy fuel residue bog down a carburetor, performance is hindered or the engine fails. Maintain efficient operations by keeping up with cleaning
A sooty plug is an indication of a rich fuel mixture resulting in frequent misfiring. Burnt plugs could mean the fuel combustion is too high or high ethanol concentration. To cure this, replace the sooty plug with a new one to prevent misfiring when cutting firewood Lean Air/Fuel Mixture A rich Air/Fuel Mixture runs cooler than a lean mixture. A lean mixture can get too hot and detonate. Too Much Compression Compression causes heat. If the air/fuel mixture is compressed too much, it can detonate. Engine Overheating Low coolant or a bad water pump can cause the engine to overheat
Carb Sensitivity and Pipe Bang. KTM/BETA/HUSQVARNA Jetting Issues and Carb Finicky-Ness is not really a carb issue. New Buzz-Term Pipe-Bang also not a Carb issue. Note: I am going to try and keep this VERY simple in order to get the points across. Intent is not to get into a fully involved technical discussion on what happens, but. . A fuel-air mixture that produces an EGT above the recommended maximum is considered too lean, even though it is still too rich for complete combustion As concerns valves in 2-cycle engines, there is a reed valve that is a flap of spring steel over a port. The fuel mixture can be pulled through it into the crankcase, but the valve closes when the pressure in the crankcase rises as the piston is on the downward stroke. Otherwise, the engine has ports without valves
That's the function of a four-stroke engine that is fitted in almost all modern car engines. A misfire occurs when ONE or more of these stages is wrong or missing. An overly lean or overly rich air-fuel mixture; Bad ignition spark / Wrong timing of the ignition spark; Low compression / Air-fuel mixture is leaking ou All the single cylinder bikes, 2 stroke or 4 stroke having a carburetor. OK the engine is running and the mixture is lean. If you notice from the engine sound OR if you see the tachometer, the engine RPM will not be steady at this point. The mixture is too lean or too rich. Try again Continued reduction of enrichment beyond a certain point may not detonate since the extreme lean condition results in a shortage of fuel to burn, and flame speed slows down. Somewhere in that lean direction, flame speed can be slowed, continuing past the exhaust stroke. That can then, like excessively rich conditions, cause a backfire in the. Also, I've just heard from my parts seller, it appears that my carb is made for a 2-stroke but my Yamaha is a 4-stroke. On that particular bike, I stated with a 3.0 (lean) and went to 2.0 (rich) and it made a drastic difference. I ended up going to the 2.5. So I experimented with a 20% difference. If the hesitation is a rich blubbery. This is caused by a rich mixture that is forcing the sparkplug to intermittently miss making it sound like a four stroke. This is not good. HOWEVER the good news is; gasoline two stroke engines are very tolerant of rich settings (most of the time) and will run fine. You'll just consume a little more gasoline than necessary, and create a little.
The overly rich condition makes the power delivery soft down low then above too lean, which gives tinny, weak power that pulls in to a decent top end. The Get ECU (with custom Slavens maps) corrects the rich and lean issues and creates a much stronger and more linear power from bottom to top. Using up every millimeter of Kreft's modded. If the mixture screw is more than 2 1/2 turns out turns then the Idle jet is too lean (too Small). When the mixture screw is less than 11/2 then the Idle jet is too rich (too large). These assumptions are based on the fact that the speed screw setting is not opened more than 11/2 turns How-To: Read Spark Plugs. Reading spark plugs is an easy way to determine how an engine is running. Now, I'm going to cover the 3 most common conditions, lean, normal, and rich. Before I get into describing these common conditions, let's go over on how one would obtain such a reading through conducting a plug chop 2,888. May 31, 2005. #4. Re: Johnson 2-stroke fuel/air mixture adjustment. Brendan,<br />You'll do best to run at a 50:1 mixture. As for the carb. If you havn't already opened it up, nows the time. Clean with carb cleaner and blow out all passages with compressed air
If the engine does not 4 stroke or give the too rich firing sound, any place on the track, it could be because the engine is running too lean ( not enough fuel ). This is easily checked by opening the needles out in 1/8 turn increments until the engine 4 strokes premium two-stroke fuel for break-in and testing. There are plenty of other fuels on the market that will perform just as well; just make sure that the fuel you select complies with the requirements listed in the user manual. O.S. specifies 12×6, 13×6-7 or 14×6 propeller sizes. As part of this review, we tested most o If the ring is taller than 2mm or darker than a Hershey bar, you're rich on the mains. If the ring is smaller than 2mm or lighter, or nonexistent, you're lean on the mains. If both plugs aren't almost identical, one cylinder may be richer or leaner than the other (if leaner then an air leak is likely on that cylinder)
BANG: Since this new upgrade has resulted into what is called a LEAN mixture (more air then fuel) we now have to increase the flow/volume of FUEL in order to get back into that sweet spot. Which for gasoline engines is the chemically efficient and complete combustion mixture of 14.7:1 (14.7 parts air to 1 part fuel) You will not get the same characteristics out of a 120 2-T that you will out of a 110 4 stroke. What you are describing here is typical two-stroke characteristics. The exhaust is a crucial part of a two stroke engines power curve. The exhaust is designed along with the porting to give a certain power curve and the curves are usually quite narrow
To start, it helps to understand what is happening inside the combustion chamber to cause that destructive pinging sound. What It Is Depending on engine load and tuning, the spark plug fires anywhere between 45 degrees down to 5 degrees before top-dead-center (BTDC) of the compression stroke and ignites the air/fuel mixture Does sound like the mixture is too lean. A half-turn CCW on the main adjustment screw might solve the problem. Occasionally a little piece of something gets into the carburator and limits the flow of fuel to the jet. The engine runs high and clear but bogs down under load and won't run without choke Most 2-stroke engines require that you mix the fuel with a special oil. In most small 2-stroke engines (like those for string-trimmers and chainsaws) the oil is mixed with the gasoline. In larger engines, the fuel is injected into the engine. This oil is required to lubricate the engine. In 4-stroke engines, the lubricating oil is in the crankcase . On a stock NA model MX-5 the timing point is set at 10 degrees before top dead centre (BTDC) when at idle and there is no load. 3. Top dead centre refers to the position of the piston. The piston is at its highest point when at TDC. The crankshaft angle is 0 degrees and the crank/connecting rod angle is 180 degrees
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. Use the table below to determine if the engine is running lean or rich 12 Symptoms of a Clogged Fuel Filter (How to Tell if a Fuel Filter is Bad) Lower Engine Performance. Any weak fuel filter will cause the engine to misfire and perform very low. Once this happens, immediate cleaning will help, but the best will be a full replacement. However, if the fuel efficiency starts to suffer or the engine behaves in an.
The EFI 2-stroke does not provide enough benefit over the carburated 2-stroke to outweigh the additional maintenance, in my opinion. I had a 2000 Yamaha Ox66 225 for 4 years on a Revenge 22 and while it was a good motor, the O2 sensor was its weak link Build a Tuned Pipe for a 2-stroke: Two stroke engines fascinate me. They are so simple and fun that I've always enjoyed tinkering with them. There are many ways to boost the power, one of which is by installing a tuned pipe. The way a two stroke motor w A 2-stroke engine makes one revolution for every power cycle. As the piston moves upward in the sleeve, it compresses a fresh charge of fuel/air mixture. The compression heats up the fuel mixture and is ignited by the glow plug. As the piston travels upward it also creates a negative pressure zone in the crankcase below the piston Example #2 The plug is showing me by the deposits on the tip of the electrode and also the deposits right on the edge of the threaded body. that it's slightly fat at idle. The white porcelain is showing a lean condition at WOT, it's not too far advanced as the total timing mark or color change is right in the apex of the ground strap curve This is more or less true for a 4 stroke engine, but for a 2 stroke there are other factors to consider: 1. Since a 2 stroke has combustion once every crank cycle (whereas the 4 stroke combusts once every 2 cycles) then the pistons top temperature can get high enough to melt it at high engine revolutions with the timing advance equal to that of.