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Post by userix on May 15, 2014 3:20:23 GMT -5
Here's a vid of my scooter idling. Is it normal for the idle to dip every so often like in the video above? I'll try to get a video of the scooter revving. Again, I made sure there are no air leaks anywhere around the carb, intake manifold.
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Freshman Rider
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Post by userix on May 15, 2014 12:59:56 GMT -5
So I upjet to a 105 jet on the carb and took it for a ride. I went wotting for a good mile and near the end of the mile, the engine started stalling out, as if it ran out of fuel, and I lost power and speed, I let go of the throttle partly and it still loses power, as if no gas. Then I let go of the throttle completely, and I get a bunch of popping. Then I come to a stop, and the engine idles fine and doesn't die and I can take off immediately afterwards without anymore issues. Does this mean I'm still running lean? Do I need to go up in jet size again to maybe a 108?
Does going to large a jet reduce top speed and low end accelration performance?
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Post by userix on May 18, 2014 17:21:36 GMT -5
I changed the main jet to 114 and pilot to 38. Just to test out. And I still get the random dying on wot issue. It really feels like it just runs out of fuel. But I pull to the side and drained the carb and a good amount of fuel drained out. It's so weird. There fuel in the bowl And the main jet is huge and I still get what feels like fuel starvation accompanied by popping when I let completely go of the throttle.
The problem doesn't happen consistently. That's what confuses me. I switched a cdi too
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Post by alleyoop on May 18, 2014 18:54:19 GMT -5
The POPPING when you let go of the throttle completely closes the BUTTERFLY really quick it snaps shut to where you have the idle set. That is a LEAN condition, it could just be that the IDLE is set to low and is closing to many of the PILOT jet fuel outlets and it runs lean and POPS. So if the idle is below 1500 or lower raise it to mayabe 1600 and see if that stops the POPPING if not then turn the FUEL RATIO mixture 1/4 Turn Counter Clockwise to feed it a little more fuel.
Alleyoop
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Post by userix on May 19, 2014 1:43:45 GMT -5
The POPPING when you let go of the throttle completely closes the BUTTERFLY really quick it snaps shut to where you have the idle set. That is a LEAN condition, it could just be that the IDLE is set to low and is closing to many of the PILOT jet fuel outlets and it runs lean and POPS. So if the idle is below 1500 or lower raise it to mayabe 1600 and see if that stops the POPPING if not then turn the FUEL RATIO mixture 1/4 Turn Counter Clockwise to feed it a little more fuel. Alleyoop My idle is around 2500-3000. And I still get the occasional pops. But the bigger problem is when I start stalling out during wot, like I am running out of fuel. The engine will start to die like there was no more fuel. This happens only after say 3-5 min of straight WOT. the carb bowl is still full of fuel after immediately pulling over when I lose power, so it's not actually out of fuel. But the engine still loses power as if it was running out of fuel, but it can start right back up after maybe attempting to start it for 10 sec. I'm at a 114 main jet now and it still has the same problem as when I was using the 105 and 108 jets. Now I'm thinking could this have something to do with the pump not pumping enough fuel due to the lower vacuum pressure during wot? But then I think if that was the case, there should have been very little fuel in the carb bowl when I pulled over immediately after stalling to check. I'm not sure what the problem can be now. As of now, I have jumped from a 102 main jet to a 114 and still encounter the loss of power after a straight 5 min wot. It doesn't feel like it got any better. I'm baffled as to what the issue really is. And it just doesn't happen all the time either. |
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Post by phatboy on May 19, 2014 4:03:39 GMT -5
as i understand, the float is suppose to maintain the fuel level not drain and refill the bowl. if the fuel level in the bowl goes down too much you could get bogging even if there is still fuel in there. some suggested the vaccum problem on my thread and suggested a better vacuum pump or an electric pump. im not sure if vacuum is my problem or some thing else. but i found a thread with links for a better vacuum pump and an electric pump for sale both cheap. scootdawg.proboards.com/thread/21099/electric-fuel-pump-install-video |
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Post by alleyoop on May 19, 2014 11:58:28 GMT -5
Idling at 2500-3000!!! You have that thing all messed up, no wonder you are having a lot of problems, it should be idling at 1500-1800 no more.
The First thing to do is ADJUST the Valves, and may I say mounting the carb backwards is one of your first problems. Reason is the front of the scoot there does not get much air and the filter has a cap on the end(but be it as it may).
Alleyoop
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Post by userix on May 19, 2014 14:43:12 GMT -5
Idling at 2500-3000!!! You have that thing all messed up, no wonder you are having a lot of problems, it should be idling at 1500-1800 no more. The First thing to do is ADJUST the Valves, and may I say mounting the carb backwards is one of your first problems. Reason is the front of the scoot there does not get much air and the filter has a cap on the end(but be it as it may). Alleyoop Valves have been adjusted .004 for both. If I drop the idle any lower, it will stall out after letting go of throttle from wot and coming to a stop. I tried 105, 108, 120 main jets and I still have the same problems. Tried. 36 and 38 pilot jet As well. The air filter of the carb is suppose to face towards the back of the scooter?? All the custom gy6 I have seen have the carb mounted with the air filter facing the front of the bike. But anyways. I tried various main jets and pilot jets and the problem is still there. Changing the carb float height didnt help either |
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Post by alleyoop on May 19, 2014 15:04:25 GMT -5
Ok, sounds like the pilot jet is not functioning and no gas is being suck out of the carb bowl, could be due to maybe the carbs angle.
Are you sure you have all the hoses connected right especially the vacuum hoses.
Can you take a picture of the both sides of the carb and how it is mounted on there with the hoses showing.
And by the way mounting the carb backwards take a good mechanic to get them to work right. And your wrong on the scoots having the carb mounted forward that is not true. What you will see is the carb in it normal position facing back and the Air Filter they put on tubing to have the Air Filter to the Side to get clean air.
Alleyoop
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Post by userix on May 23, 2014 22:21:37 GMT -5
Ok. I carried some tools while riding today and turns out I was runnin into fuel starvation issues. As soon as I hit the bogging problem at wot, I pulled over right away and dropped the float bowl. The level of fuel is very low. Now I have since them replaced the pump with a brand new mikuni and checked all vacuum lines and fuel lines. There are no leaks anywhere and the connections are all good. I noticed the check valve that was between the pump and carb was seemed very restrictive. So I removed if completely. I still have the problem though after all this. I still run into fuel starvation issue on long wot sessions. Even with a pump and the check valve removed, I still see bubbles appearing from the pump outlet to the carb. But again no fuel leaks from any hoses from the tank to pump to carb.
Do I need to upgrade to an electric pump setup?
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Post by alleyoop on May 23, 2014 22:34:46 GMT -5
I don't want to get pissy here but someone has got to put some sense into you. Mount that damn carb the right way, what do you think mounting that way is going to give you, might look cool but runs like and cannot get it tuned right. That is the start of your problems always has been. I mean idling at 2500-3000 when it should idle around 1500-1800 you have to know something is flat wrong. You have to have the brake on all the time so it does not take off on you. Also with the wheel spinning that fast when its on the ground and you have the break on so it doesn't take off on you puts a load on the motor and if you lower the idle it will die.
So the first thing is mount that carb the right way, and then we can work on getting the idle down to where it should be.
Alleyoop
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Post by geh3333 on May 23, 2014 22:39:00 GMT -5
I set my idle to 2000 rpms , I know it's a little high but I'm running lean on decel and it will somtimes stall if set to 1800 rpms . Of course my carb is big and can be a pain to tune in perfectly . I should just get a bigger pilot jet .
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Post by alleyoop on May 23, 2014 22:45:50 GMT -5
How do you know it is running LEAN on decel Geh3333?
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Post by geh3333 on May 23, 2014 22:50:03 GMT -5
I have popping on decel . Other than that I don't know . My plug is slightly dark, so I know it's not normally running lean .
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Post by alleyoop on May 23, 2014 22:54:28 GMT -5
Since your not running with a carb that has an ACV valve the only thing you can do is richen up the fuel mixture or high idle
But looking at your sig your way over carbed for your motor mods.
Alleyoop
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..BAD TO THE BONE..
