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Post by JerryScript on May 9, 2014 12:20:40 GMT -5
Dipping in RPMs during idle is usually and indication of an air leak, or fuel flow problem. Since you have those air bubbles at times in your fuel line, I would say you need to find the source there before attempting to find air leaks.
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Post by userix on May 9, 2014 15:03:05 GMT -5
Dipping in RPMs during idle is usually and indication of an air leak, or fuel flow problem. Since you have those air bubbles at times in your fuel line, I would say you need to find the source there before attempting to find air leaks. But the dipping in idle only happens if I quickly twist the throttle to wot and let go. If I let it idle by itself, then then idle is consistent and can idle all day long. According to the af mixture screw tuning guide linked by alleyoop, if the idle dips below normal idle after a quick throttle twist, then it means it's too rich. But that goes against the fact that I am too lean, as indicated by popping on deceleration. I'm confused as to what is really wrong lol |
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Post by alleyoop on May 9, 2014 15:07:57 GMT -5
No actually If the IDLE drops down below your set Idle and it kills the motor that is a sign of it being to RICH.
No your pilot jet is not to small maybe TO BIG.
POPPING during decel is LEAN it could be caused by your IDLE set to low the idle should be 1500-1800 where ever it idles the smoothest.
If the Carb has a ACV valve that is what feeds it extra fuel on DECEL for the sudden closing of the throttle so it does not run lean.
Now from WOT and you let go of the throttle and it starts to pop, when does it start to pop almost down at idle or as soon as you let go of the throttle when the rpms have yet not dropped. That could be caused by your AIR BUBBLES which would make it run lean not getting gas.
So Like Jerry said I would FIRST find what is causing the AIR BUBBLES because that is what is throwing everything else off.
Alleyoop
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Post by userix on May 9, 2014 20:24:10 GMT -5
No actually If the IDLE drops down below your set Idle and it kills the motor that is a sign of it being to RICH. No your pilot jet is not to small maybe TO BIG. POPPING during decel is LEAN it could be caused by your IDLE set to low the idle should be 1500-1800 where ever it idles the smoothest. If the Carb has a ACV valve that is what feeds it extra fuel on DECEL for the sudden closing of the throttle so it does not run lean. Now from WOT and you let go of the throttle and it starts to pop, when does it start to pop almost down at idle or as soon as you let go of the throttle when the rpms have yet not dropped. That could be caused by your AIR BUBBLES which would make it run lean not getting gas. So Like Jerry said I would FIRST find what is causing the AIR BUBBLES because that is what is throwing everything else off. Alleyoop Ok. So it makes sense now, my pilot jet is probably too big because that is a problem I have been having for a while now. Now as for the popping, it occurs as soon as I let go of the throttle. Sometimes it happens maybe a little higher than halfway down from idle. But it mainly immediately after I release the throttle and the RPMs are still fairly high. It's nowhere near idle rpm speeds when the popping does occur. So as of now, it looks like the pilot jet might be too big and my main jet might be too small? |
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Post by alleyoop on May 9, 2014 20:34:02 GMT -5
Your main jet has nothing to do with the De-Cel popping when you let go of the throttle the needle drops down into the main jet and shuts off all gas coming out of it because the BUTTERFLY is closed and closing the air from creating pressure in the venturi.
This popping stuff is all due to the fuel from the pilot jet. Did you change the pilot jet and to what size?
Alleyoop
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Post by userix on May 10, 2014 3:31:42 GMT -5
Your main jet has nothing to do with the De-Cel popping when you let go of the throttle the needle drops down into the main jet and shuts off all gas coming out of it because the BUTTERFLY is closed and closing the air from creating pressure in the venturi. This popping stuff is all due to the fuel from the pilot jet. Did you change the pilot jet and to what size? Alleyoop I use a CVK Keihin carb and the pilot jet size is 36. And I haven't changed this jet since I got the bike. But because I still run into the occassional stalling out problem during WOT, that still means my main jet is too small? And once I come to a complete stop, the engine just dies. But it usually can be started again right away. As for the pilot jet, I am really confused now. Because I had the issue where a quick twist of the throttle causes my idle to drop way below normal idling RPM, it means my pilot jet is too rich, or too big. But at the same time, I still have the decel popping noise problem, which I just checked today during a ride, it could occur at any range of the RPM, from near WOT and also down closer to the idling RPM. And decel popping is indicative of a lean condition, which mean my pilot jet is too small. I'm not sure with the two opposite problems I am having, if the pilot jet is too small or too big. |
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Post by JerryScript on May 10, 2014 9:43:26 GMT -5
Have you tracked down the source of the bubbles in your fuel line yet? Bubbles mean extra air, which could make it lean when they are present.
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Post by userix on May 10, 2014 10:04:16 GMT -5
Have you tracked down the source of the bubbles in your fuel line yet? Bubbles mean extra air, which could make it lean when they are present. It weird, I actually don't see anymore bubbles in the fuel lines right now. Not sure what happened but so far they are gone. But the problems still are present. So mind boggling... |
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Post by alleyoop on May 10, 2014 12:40:50 GMT -5
Well a #36 Pilot jet is to BIG plain and simple, if it came like that its to big for you motor. People think dump a gallon of fuel in and the scooter or put on a bigger carb to get more speed WRONG, it actually floods the motor and the motor looses power with to much fuel.
So first go down on the pilot jet to stop it from loading up the motor at idle. Then we can work on other problems, one thing at a time.
Alleyoop
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Post by userix on May 10, 2014 19:15:29 GMT -5
Well a #36 Pilot jet is to BIG plain and simple, if it came like that its to big for you motor. People think dump a gallon of fuel in and the scooter or put on a bigger carb to get more speed WRONG, it actually floods the motor and the motor looses power with to much fuel. So first go down on the pilot jet to stop it from loading up the motor at idle. Then we can work on other problems, one thing at a time. Alleyoop But what about the popping on decel? Is that not caused by the pilot jet being too small? Because the throttle is completely closed during the deceleration pops. Update: just took a ride out and wotted it straight for a mile. At the end of that mile, I started losing power as if I ran out of gas but I kept the throttle wide open and I started getting pops while the throttle is held open, but I am losing power and speed at the same time, as if running out of gas. I checked the gas lines during this time and there are no bubbles at all. Fuel is flowing well. But as soon as I pull over and stop, the bike is idling fine and I am continuing to ride right now. Is this still a lean condition of the main jet? I haven't messed with the main or pilot jets yet Just throwing this out here but could a faulty cdi cause any of these symptoms I am experiencing? |
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Post by alleyoop on May 10, 2014 19:35:37 GMT -5
POPPING AT WOT is TO MUCH FUEL your main jet is TO BIG. What exactly do you have on the scoot?  Free flow Filter--?YES OR NO? Free flow Muffler--?YES OR NO? What size Carb--? What size Main jet--? What size Pilot jet-- 36 |
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Post by userix on May 10, 2014 19:53:11 GMT -5
POPPING AT WOT is TO MUCH FUEL your main jet is TO BIG. What exactly do you have on the scoot? Free flow Filter--?YES OR NO? Free flow Muffler--?YES OR NO? What size Carb--? What size Main jet--? What size Pilot jet-- 36 Free flow exhaust yoshimura. Free flow filter. (Mushroom looking cap) Carb size is keihin 26mm Main jet 102 Pilot 36 But I still have popping on decel and I lose power right before the popping starts during wot. It still feels like "running out of gas" feeling, which. I believe means it's lean right? |
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Post by alleyoop on May 10, 2014 19:58:26 GMT -5
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Post by userix on May 11, 2014 16:39:00 GMT -5
I thought you said the main jet was too small. The popping is still only happening on decel. What jets would you recommend I use for my setup as stated previously? Sorry I might have been unclear before the quick twist of the throttle test, the idle dips below normal idle after I release the throttle. Not during the quick twist of he throttle. When I quickly twist the throttle, the rev goes up normally and when I let go, then the idle drops way below normal but return back to normal after a couple seconds.
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Post by alleyoop on May 11, 2014 16:50:12 GMT -5
I thought you said the main jet was too small. The popping is still only happening on decel. What jets would you recommend I use for my setup as stated previously? Sorry I might have been unclear before the quick twist of the throttle test, the idle dips below normal idle after I release the throttle. Not during the quick twist of he throttle. When I quickly twist the throttle, the rev goes up normally and when I let go, then the idle drops way below normal but return back to normal after a couple seconds. What they hey, you apparently have TWO PROBLEMS BRO. you say it POPS AT WOT that is caused by TO MUCH FUEL. Then you say you have popping on De-Cel that is cause by NOT ENOUGH FUEL on DE-CEL. POPS at WOT mostly caused by the main jet been to big. POPS at De-cel not enough fuel fed when the butterfly is suddenly closed either the IDLE is to LOW or richen up the Fuel Mixture or both. Get a Video going on the center stand and Give the throttle a quick twist to see what it does. Alleyoop |
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..BAD TO THE BONE..