07-11-2014 06:48 AM. Maybe I will sum this up and post it on the Yahoo Tweecer group. Dont know if it was jetted bought it used. Ask any serious mechanic and he will tell you that you can know almost everything about your engine just by looking at the spark plugs. The third, the carbs used on these bikes have an off throttle air circuit system that works with the SAS and causes it and nothing can be done to eliminate it, only thing is not every 950 does it seemingly or some are worst than others, how do you explain that, I have no exhaust leaks on mine either BTW. Popping on Deceleration: Lean or Rich? - Motorcycle Fuel Mixture Problems Explained. Maybe you're looking for the exhaust sound on decel that some call a "burble". PIPNUM Fuel - Shut-Off Decel Min PIP To Remain OL 4. Timing will only really be a problem on older bikes that still has points ignition. I had to bypass the PCV for now, so I have a the intake plugged, TB plugged, and a breather on the valve cover and a hose from the PCV to a catch can. It's always a good idea to take care of popping on deceleration before it becomes a big problem.
Backfiring could also result from poor timing. 3mph on my CRAPPY Nitto drag radials. My next 4 passes all would have been under the 11. If too much fuel is added to the engine, it may not all burn up before the exhaust valves open -- letting unburned gasoline into the red-hot exhaust headers, where it can combust and lead to a backfire. This doesnt make sense to me... adding extra unburnt fuel into the exhaust shouldnt make it pop less. If you snap the throttle fully closed, engine RPM will lower faster, and the constant RPM change will keep the Fuel Injection ECU in open loop - and the BoosterPlug will be able to provide it's fuel enrichment to remove the backfire. A rich mixture is more common and not necessarily detrimental to your engine. If the change in airflow is outside the range of the EFI mapping, you may have to get the EFI re-mapped. Last but not least, another pretty common reason for popping on deceleration is cracked or brittle vacuum lines. Probably the most common vacuum leak location on motorcycles is the rubber intake boots, that connect the carbs to the cylinder head. And that was 4 years ago, it hasnt changed no matter what ive done with the dashpot or any other component of the intake or fuel system. I have many friends that are outstanding mechanics and we chased everything we could to figure it out. Popping on deceleration lean or rich text. I am not even sure if it is OL or CL during this big bang.
But if you just ease off the throttle slightly, the RPM will sink slower, allowing the FI-ECU to return to closed loop operation, where the BoosterPlug is inactive. Dealing with vacuum lines is never fun. 0 runs lean, really lean, I fry plugs every 3K miles and have all kinds of pinging. Causes: Air Leaks: Any source of fresh air into the exhaust system can create or. If your motorcycle has a carburetor, it is most likely tuned too lean. Other reasons for popping on deceleration. If you're set up for 14. Look for a possible timing issue too. If all that checks out then you can alter the fuel curve at closed throttle to help this problem. Popping on deceleration lean or rich internet applications. The throttle valve is in the idle position, fuel does not flow. Lean when the throttle is closed and the engine is rotating well. The same will be true if you moved to a much lower altitude which caused a lean condition. If you are using a PCIII then go into the 0% column of the software and alter the fuel curve from 1750-5500rpm. Carb sync is needed.
It's used as a safety precaution. The dashpot is like a door closer; it keeps you from slamming the throttle plate closed, by closing it over a period of about one second. Popping on deceleration can be caused by both lean or rich Air-to-Fuel mixtures. Sometimes fires at the wrong time, then exhaust popping can become. Location: along the shore of Mishigami. Sometimes, it seems that only looking at the carbs the wrong way is enough to make them stop working, so it's quite common to disassemble and clean them. If the engine is running to lean, the spark plug can look greyish white. When I decelerate (usually in 2 or 3 gear), once the RPMs cross below 2000, I hear a rapid popping sound from my exhaust - disappears around 1200 RPM. Popping on deceleration lean or rich meal. Becomes too lean to burn reliably in the combustion chamber. In fact, one should expect a well-tuned high performance. Make sure that the float is set to the correct height. I haven't had a chance to try anything to fix this yet, but I was just thinking about the problem some more. Gap formed by the throttle valve and carburetor throat.
Thank you, Last edited by A. H. Y; 01-14-2018 at 11:37 AM. Leaning the idle mixture (turn screw out on Non-PD carbs) of the offending out of sync carb, should help abate the fuel buildup in the exhaust when the slide is in it's closed position. CBRXXRAGE Posted February 5, 2005 Share Posted February 5, 2005 I have a 97 and it has a full system Yosh.
You can also check the condition of the spark plug electrodes. I run VM38 Mikuni with long velocity stack length, a custom one into two exhaust muffler system with absolutely no leaks, a Pazon fully adjustable ignition system, a 10. Popping on decelleration - Motorcycle Jetting & Fuel Injection. I said what did you do, nail the gas? Twin Cam Harley Intake Seals Replacement. What repairs can fix the P0172 code? Your bike may be running lean if there is an air or vacuum leak somewhere on the intake boot between the carb and the engine intake. I didn't think that this really mattered.
Thanks everyone - this is great information!! Popping from exhaust lean or rich. Once you've identified the problem, it's important to fix it sooner rather than later to avoid any potential damage to your engine long term. A bit of popping from the exhaust on deceleration is not that bad for your engine and should not cause any immediate damage, especially if the timing is correct and the engine does not overheat. Some Magnetti Marelli bikes responded by having a -60 put in this column while most Delphi bikes respond by inputting a +25.
380" lift and unless I run a high idle it still pops so no idea what causes it? No, exhaust backfires are more likely due to lean misfire. Leaks in the exhaust system can provide oxygen to enable the unburnt fuel to ignite with an ember from the piston chamber. Why This (normally).
DSFTM Fuel - Shut-Off Decel Min Time At Part Throttle 4 Sec. Since putting the stock exhaust back on(except 2. Better double-check it. Be aware that you don't richen it too much.
Also make sure that you synch the Throttle Position so that it reads 0 while the bike is idling. I increased my fuel pressure so I dropped my offset a little, I must have over compensated becasue I didn't have this problem with the bigger offset and lower fuel pressure. More 'occasional'.... I have replaced my O2 sensor several times but didn't know about the issues with the Bosch universals. It is not only much quieter but also does not allow the fresh air to enter the exhaust due to reversion. CTDFSO Fuel - Shut-Off Decel Time To Enable 1 Sec.
So, yes, if you lean out your engine, going from 12:1 to around 14:1, your engine will run a bit hotter. 01'' W. Posts: 1, 746. But why does a lean mixture cause the engine to create popping and crackling noises from the exhaust? The best way to check whether the exhaust header gaskets or bolts are causing a popping sound on deceleration is by removing the exhaust and inspecting them for leaks.