This explosion is meant to take place in the combustion chamber of your engine and when it doesn’t, this causes an interruption in the engines function. Newer Virago carbs have an ‘enricher circuit’ which cuts in on deceleration to help this problem. It application is truly profound and if you have the time I highly recommend a reading of the Bernoulli family biography. As of yesterday, the backfiring problem has been resolved. Fifteen riders showed and off we went. A man named Daniel Bernoulli (1700-1782) was the first one to describe the effects of a venturi. Ride safe, Is backfire when decelerating a bad thing? We are brothers who got hooked after our first whiskey throttle. The cheapest solution is to by pass the emission system. 12. Comment below and let me know if I helped you out! These can get filled with dirt and “gunk”  preventing them from functioning as they should. IN REGARD TO THE COMPRESSION BACKFIRING PROBLEM WHEN DE-ACCELERATING, I THINK I MAY HAVE A CURE. not just once or twice, but on every little hill where I would decelerate. The mixture control valve works exactly like a flush valve for a commercial toilet! 1/06, Note: This Tech Article was created from the VOC site data. I like to think of it as skipping a heart beat. Also if its EFI you may want to get some spray cleaner and clean the throttle bore. I have gathered up all the information I could find on the subject and I hope it helps you gain some knowledge as well as that lost. When it comes to something with several connections and moving parts, it’s smart to snap a few quick pics for reference if needed. . Can you believe it!! 1 decade ago. There are a few different methods you could go about checking for an exhaust leak. Clean the air filter (should be doing this regularly) lube it and seal it with a thin layer of grease to the air box housing. Backfires on deceleration It can be tested with a vacuum pump. This thread is archived. Sometimes the issue can be as simple as the levels of Octane in your fuel. Editor’s note: Ted has requested that this information remain proprietary for use by Virago owners only and not to be used for commercial purposes. This particular morning, after starting the bike and cutting the choke back half way, the phone rang . It sits in the garage over the winter. It doesn’t do it all the time, so when it does it startles me. Archived. The air induction valve is the culprit. Sometimes you can really feel the cut out of power for a brief moment. Go check out my article on the best goggles in 2019! Should I Use Pump Gas or Race Gas in my Motorcycle? In the two and a half years I have owned it (bought new) I have enjoyed almost every one of the 39,000 miles I’ve put on it. However, many times, for different reasons, the air … If the exhaust pipes have ever been removed or replaced of if the exhaust gaskets have been stressed in any way, replace the gaskets. There are a few other things that can cause a backfire such as: weak or bad fuel pump, low fuel pressure, clogged fuel filters or anything that might cause an unbalance in the air-to-fuel ratio. The internal combustion engine of your motorcycle has a power stroke where the compressed air and gasoline mixture is ignited by the spark and pushes the piston down. The backfire is gone, the engine runs fine and the spark plugs are the color they are supposed to be. Recently I removed the rear wheel from my motorcycle and had to exert pressure on the front pipe in order to extract the axle bolt. The backfire is gone, the engine runs fine and the spark plugs are the color they are supposed to be. … proxemics. ...You can damage the engine by running too lean or rich. A backfire is an explosion that happens within the intake or the exhaust of your motorcycle. Discussion Click here to cancel reply. I was afraid at first that the mixture was going to be too lean. 2002 Yamaha V-Star 1100. Deceleration backfire is caused by fuel burning in the exhaust manifold or header. I tried it and it worked. This effect is what makes airplanes fly and motorcyles backfire. As some have said, running straight pipes on the newer motors can cause this because of the tight specs. My bike does not take much choke in the morning to get it started and as soon as it is started, I cut the choke down to about half choke. Since the publishing of this recommended fix, several other members have asked for solutions to backfiring problems. I SAY VIRTUALLY ELIMINATED AS I WILL STILL BACKFIRE WHEN QUICKLY BACKING OFF THE GAS IF I’M AT HIGH ALTITUDE. More From Reference. Then, once on the bike, I run the choke down the rest of the way. There are many variables when discussing the cause of a motorcycle backfire. Start up the bike and look around those connections for bubbles building up. The temperature here today was 105 degrees with a heat index of 110 … After 62 miles, I finally found the problem: Below are actual problems submitted by Virago Owners and Club members. 2 Posts . An engine backfire is an explosion produced by an internal combustion engine. How to Install Exhaust Gasket on a Motorcycle; Carburetor Models Check these out; Make Sure to Watch All EFI Mapping videos in Our Upgrade Categories; Tags: EFI mapping. I tried it and it worked. If your motorcycle has sat for a lengthy amount of time then it is very possible the old gas has sat in the carburetor and the impurities have settled, causing a clog and your engine to run poorly or maybe not run at all. In the event of a backfire when accelerating, the Harley backfires through the combustion chamber of the motorcycle. I was asked the question the other day, why does my motorcycle keep backfiring? a backfire is caused by incorrect timing or not enough back pressure in the exhaust pipe What causes popping in engine Car won't rev ocer 1700. Its the air leaks caused when the gaskets wern’t replaced and other leaks sealed when they were installed. How to Use a Personal Loan Calculator . You will save alot of … This explosion is meant to take place in the combustion chamber of your engine and when it doesn’t, this causes an interruption in the engines function. This applies to engines that use a carburetor for its fuel management system instead of fuel injection. In some cases, a backfire may cause a burst or flame to shoot from the vehicle’s exhaust. What a difference in the performance once I closed the choke . Following are some of the added recommended fixes and actual solutions, Specifications Yamaha Virago XV535 1981-1994, Yamaha Virago XV750 – XV1000 + TR1 1981-1983 Specifications, 1984 and later Yamaha Virago XV series specifications, Short Takes–Misc. This will cause excess fuel to pass into the exhaust and go BANG! One of the easier things to check off the list would be the spark plug. Generally, there are a variety of ways it gets there, and a variety of things that can make the backfiring worse. I will get right to the point. Basically I lost my baffle and I will only get a new one tomorrow, is it gonna damage my engine? I had just set the valves, balanced the carbs and changed the oil and the bike ran great on three previous rides. Air should be expelled through the large pipe for a short time and then stop quickly. A motorcycle backfires when the motorcycles engine is experiencing an emission system malfunction, resulting in a mistimed explosion in the cylinder or exhaust. When an engine is running too rich this means that there is more fuel present in the combustion chamber than there is air. Can be deceleration from high speed (60-80 kmh) or from low speed (40 - 60 kmh). He stated that the thimbel is the right size and is cheap. Other culprits could include corroded or cracked spark plugs or spark plug wires, a faulty ignition coil, a clogged air filter, or engine timing issues. I recommend always using a premium high octane fuel for your bikes. Fresh air is drawn in through those tiny holes and provides sufficient oxygen to ignite the unburnt gases inside. This occurrence can result in a flame emitting from the exhaust as well as a LOUD popping sound. These are just two different ways of saying the same thing. Happy now, although a bit dishearted about the dealer….Joe Addison. 8 posts Deceleration backfiring Deceleration backfiring. (Virago Owners Club), Since the publishing of this recommended fix, several other members have asked for solutions to backfiring problems. What happens is that the mixture leans out enough to where is fails to ignite consistenty. Additionally, there could be a problem with the valve springs. But in the last 4,000 miles it has a tendency to do a compression backfire when I have been holding the throttle at a steady pace and then let off fairly fast. Any time the exhaust is “opened up” the condition of deceleration pops is … Read through them and see which one matches your particular problem. Its too small. Here’s … The heat from the pipes then ignites the vapor and boom, backfire. Will suggest to make sure it is safe for map sensor type, that way it shouldn't mess anything up. Your carburetor has 4 components inside that make all the magic happen when you get a hand full of that whiskey throttle. NOTIFICATIONS. I suspect that this allows a much leaner mixture to be introduced into the exhaust manifold. Mac McCurdy. Backfire? It is still backfiring. When you suddenly close the throttle, the incoming air is choked off and the closed throttle also causes the bike to return to idle on the very lean idle circuit. darbytx. when the engine is running too lean this means the opposite of rich; there is more air than there is fuel in the combustion chamber and is basically starved of fuel. The stock muffler on a motorcycle is specifically designed to ensure the motorcycles engine runs the way it is supposed to. . He stated that the thimbel is the right size and is cheap. Sort by. QUICKLY draw a vacuum on the small pipe while blowing through the end of the valve (where air is drawn in) seal the valve tightly with your lips. MESSAGES. Backfiring is bad because it is a fuel ratio malfunction and will result in a loss of power. The mixture control valve, which is made of plastic runs $83.00 here in Wichita Falls. I finally cured the decel backfire by installing new exhaust manifold gaskets which apparently were letting oxygen rich air to be drawn into the pipes and igniting unburnt gases introduced by valve overlap. What it is, is incomplete combustion, fuel is left over, and shot into the exhaust pipes. On FI bikes DO NOT “blip” the throttle when decelerating. You need to remove the carburetor from the bike and drop the fuel from the float bowl. Does any one else have any theories? I recommend you use a squirt bottle and soak the connections throughout the full exhaust system; headers, muffler slip on and welds. So, the popping you are hearing is not back-firing. A machine, must be carefully maintained and assembled in order to perform to its full design potential. Running the motorcycle too rich  or too lean can also cause the internal temperatures of the combustion chamber to get too hot and fry your engine! Stay on the throttle my friends! This makes the backfire sound you describe, and only when the brakes are off and at a certain speed and rate of decel. Good luck with it, Rick, I own a 1983 virago xv920k with which I have had the decel backfire problem. This worked for the 1984 and 1985 XV1000, it should work for the other bikes as well. There are several reasons why a motorcycle sputters. If you want to get rid of the noise, you will need to de-tune your motor. The combustion chamber and the exhaust pipes and wiring are all part of a Harley Davidson exhaust system. This, in turn allows some unburnt fuel to get into the exhaust pipes. The temperature here today was 105 degrees with a heat index of 110 degrees. When either of these happen the fuel may find its way into your exhaust and explode from the heat of the exhaust. This principle has a dramatic demonstration any one can perform. Did everything ,went through the carb ,gas ,points,ect. I like to think of it as skipping a heart beat. A COMBINATION OF INSTALLING HIGH QUALITY SPARK PLUGS (SUCH AS SPLIT FIRE) GAPPED METICULOUSLY, CLEANING THE PLUGS AND CHECKING THE GAP EVERY 1,000 MILES, AND USING AN OCTANE IMPROVER IN THE GAS HAS VIRTUALLY ELIMINATED MY PROBLEM. Another reason why your motorcycle engine backfires on acceleration is that there may be a problem in your carburetor. It sounds just like a rifle shot. Our names are Tyler and Casey and this is where we share our experience and knowledge as motorcycle enthusiasts! 55 comments. My car is running great as far as stop and go, cruising, WOT, etc., but there's one small issue (hopefully) that I'm trying to tune out. When I had the 600 mile service, the dealer installed short-reach plugs. When spraying some carb cleaner to find - Answered by a verified Motorcycle Mechanic Oh! The XV1100 takes long-reach plugs. As the speed of a fluid increases its pressure decreases. HSATF Member. Many people like to modify their bikes with a new exhaust for better performance or sound BUT this comes at a risk. Joe Beautz. darbytx. DISCUSSIONS. On a recent ride, my bike was really starting to backfire . The bike started backfiring bad when decelerating. Hopelessly confused by information #1. supershaft, Sep 26, 2011 #2. Hard starting, backfires on deceleration, when warmed up, feels like plug foul and will shut off engine, turn off key wait a few seconds and turn on key fuel pump will run 3-4 seconds then it is hard to start but will eventually restart and run okay for 3-4 miles and then do it all over again.