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Post by rcq92130 on Jan 14, 2015 20:19:08 GMT -5
That is UPSTREAM of the carburetor and will not affect the a/f mixture in any meaningful way. The manifold - which is DOWNSTREAM (i.e., after) the carb - if leaking will let in air that is not mixed with gas since that air didn't go thru the carb. That is not true it will effect the Air to Fuel ratio it will suck in extra air and make it run LEAN which by the way it appears to be doing. A bouncing IDLE is a LEAN condition you either have the Carbs Air Fuel Mixture adjusted to lean or you have an AIR LEAK. Check out the TIPS AND TRICKS section I have written many fixs for just about everything you may run into. I got tired of typing the same things over and over so I wrote them up and posted them for people to go and learn how to do some of the adjustments and or fixs. You will actually find one for BOUNCING IDLES. Alleyoop OK, I'll bite ~~~ do not see how this would materially affect a/f ratio. A leak upstream of the carb is no different than a slightly less restrictive air filter. Whatever air that gets into the carb inlet will suck gas past the needle according to the venturi created; simply air mass x velocity. More air getting in will suck more gas, keeping the a/f ration nearly the same. A large air leak might require a larger jet (or, fixing the leak), but how will it significantly affect ratio at idle? |
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Post by geh3333 on Jan 14, 2015 21:38:45 GMT -5
That is not true it will effect the Air to Fuel ratio it will suck in extra air and make it run LEAN which by the way it appears to be doing. A bouncing IDLE is a LEAN condition you either have the Carbs Air Fuel Mixture adjusted to lean or you have an AIR LEAK. Check out the TIPS AND TRICKS section I have written many fixs for just about everything you may run into. I got tired of typing the same things over and over so I wrote them up and posted them for people to go and learn how to do some of the adjustments and or fixs. You will actually find one for BOUNCING IDLES. Alleyoop OK, I'll bite ~~~ do not see how this would materially affect a/f ratio. A leak upstream of the carb is no different than a slightly less restrictive air filter. Whatever air that gets into the carb inlet will suck gas past the needle according to the venturi created; simply air mass x velocity. More air getting in will suck more gas, keeping the a/f ration nearly the same. A large air leak might require a larger jet (or, fixing the leak), but how will it significantly affect ratio at idle? You are absolutely correct rcq9130. The only way I can see it affecting anything is if it was a big crack that would flex in a way that one second its closed and not leaking much and the next second its wide open letting in a ton more less restrictive air , but lol its not going to cause what he is describing. The only time the intake hose would flex would be when riding and hitting bumps. When stopped at a light it should go back to normal idle . |
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Post by JerryScript on Jan 14, 2015 21:47:34 GMT -5
alleyoop is exactly correct, I've tried this myself. When I originally purchased my BBK, I first installed the uni air filter and took it for a spin, wanting to see if it gained anything like people said it would, but I hadn't jetted for it. I barely made it around the block, bucking and stuttering and all kinds of problems. Put the stock airbox back on, and it ran great for the next week till I installed the BBK. After installing my BBK, I was running with a uni and had it all jetted great. I was experimenting with the idea of using my stock airbox as a toolbox, and put it back on to see how I would need to run extra brackets for the added weight of tools. About that time, I had to go to the corner store for something, and I barely made it there and back, once again bucking and stuttering like crazy. Put the uni back on, took her around the block, and it ran great. Your jetting and tuning of your carb is always done based on the airbox and exhaust installed (and other factors). If there is any change to either, it can cause problems with your a/f mix. After all, it's common knowledge you often have to upjet when installing a uni to compensate for the extra air being brought in.
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Post by onewheeldrive on Jan 15, 2015 0:59:31 GMT -5
Either way, it wouldn't hurt to clean the carb, if you haven't lately. All that air coming in through that crack is (or was) bypassing the air filter. I bet if you take that tube off the carb and run your finger along the inside of the tube, you'll feel dirt, and possibly even see some dirt along the opening of the carb--- largely depending on the size of the hole where the crack is.
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Post by lain on Jan 15, 2015 5:28:57 GMT -5
When I had the airbox on mine I had a crack right where your crack is. I went the frugal way and used what I had at the time, duct tape and electrical tape... I got the airbox nice and warm by running it under hot faucet water (it was very cold at the time, last winter) to make sure it wouldn't crack more while I was fiddling with it. I dried it off then made sure everything looked nice and straight. Then I wrapped duct tape around the part where the "hose" connects to the box and firmly pressed the duct tape on making sure it was applied evenly and there was no leaks or cracks. Then I took the electrical tape and wrapped it tightly around the hose and the box, used about half a roll alone making sure there was no cracks. Then just for added measure because I know how electrical tape likes to come off when the weather changes a lot, I put some duct tape around the box to hold the electrical tape, and the end of the electrical tape where I finished wrapping. JerryScript Nice idea for the toolbox made out of an old air filter. I think I might use that once I'm back on the road. |
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Post by alleyoop on Jan 15, 2015 12:59:07 GMT -5
Well Jerry, all we can do is tell them what the most likely problem is and they can take the advice or not. I did not want to mention it because it is rare but a bad CDI can also cause the same results internally with a bouncing timing.
Alleyoop
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Post by rcq92130 on Jan 15, 2015 15:50:19 GMT -5
Alley
What's the point with being antagonistic to your own members simply because they ask "Why"?
Most come here because they are interested in learning. Some might be lazy and just want to be told what to do to fix a problem, but (I think) most actually like learning why things are as they are. You can see that in the spirited back and forth between members as they share experiences and thoughts about problems.
You know more than anyone else here, but when asked "Why" you seem to become angry and belittle people. Why?
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Post by murkyapricot on Jan 15, 2015 16:52:06 GMT -5
Alright guys so I''ll pick up that airbox tape after the weekend and see if that does anything and check back in.
I'm really hoping it's not a carb issue simply because I have no experience working on engines in general, although it is probably time that I learn.
I have some mechanical experience, I'm actually a rickshaw mechanic so I tend to have to fix things that don't necessarily have a specific right way to do it, so I'm always up for a challenge.
I have watched some videos of removing and cleaning carbs, I'm just terrified of getting that deep into a project for the first time lol , if it comes down to that then so be it.
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Post by alleyoop on Jan 15, 2015 17:04:27 GMT -5
If you read the few nay sayers they did not ask why they said no way that would cause the bouncing then jerry chimed in and I just reminded him that one can tell someone what most likely is causing the problem and they can follow through and see if it solves their problem or go in a different direction. Notice the nay sayers did NOT suggest a possible cause or possible fix they just said what I said would not cause the problem.
Notice I try not to respond to much anymore and you can see why. I do get a lot of guys that want my input PMing me with their problems and or questions. As a matter of fact I just answered one just now. Now ask yourself why are some on here PMing me and NOT posting their problems? Does that maybe turn on a light up there for you, I know why and the ones that want my input tell me why they are not posting their problem they see what can happen and have seen it to many times.
Alleyoop
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Post by JerryScript on Jan 15, 2015 17:25:02 GMT -5
What it boils down to is the different way people communicate. Some people think of a request for help as a general discussion about the possible problem. Others think of it as a trouble shooting request where step by step methods are used to eliminate possibilities. As a troubleshooter, alley understands that the discussion aspect can get in the way of the OP's issue being fixed. The various suggestions keep the person asking for help from following a methodical approach to fixing their problems, and instead confuse them.
I'm not taking any sides here, there is no need to, this is the downside to forums we are forced to accept. The upside is that all these various thoughts and opinions are available in times when standard troubleshooting fails. We need both, regardless of how frustrating it can be for one forum member or another. We also need to fully utilize our ability to not press the respond button based on an emotional response, but instead think things out. Together we can help just about anyone fix just about anything on our scooters!
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Post by scooter on Jan 15, 2015 19:41:22 GMT -5
Alright guys so I''ll pick up that airbox tape after the weekend and see if that does anything and check back in. I'm really hoping it's not a carb issue simply because I have no experience working on engines in general, although it is probably time that I learn. I have some mechanical experience, I'm actually a rickshaw mechanic so I tend to have to fix things that don't necessarily have a specific right way to do it, so I'm always up for a challenge. I have watched some videos of removing and cleaning carbs, I'm just terrified of getting that deep into a project for the first time lol , if it comes down to that then so be it. Don't sweat the carb. They are simple and have few parts. Take pictures of all sides of the carb to make sure you can see what goes where, then take pictures as you remove parts. If you need to, look at the pictures as you put it back together. It's about a thirty minute job to take it apart, clean all the parts and spray carb cleaner through all of the holes in it, and put it back together again. The biggest problem I have is getting the sometimes very tight screws on the outside loose. Pliers come in handy for that. |
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Post by geh3333 on Jan 15, 2015 20:43:23 GMT -5
alleyoop is exactly correct, I've tried this myself. When I originally purchased my BBK, I first installed the uni air filter and took it for a spin, wanting to see if it gained anything like people said it would, but I hadn't jetted for it. I barely made it around the block, bucking and stuttering and all kinds of problems. Put the stock airbox back on, and it ran great for the next week till I installed the BBK. After installing my BBK, I was running with a uni and had it all jetted great. I was experimenting with the idea of using my stock airbox as a toolbox, and put it back on to see how I would need to run extra brackets for the added weight of tools. About that time, I had to go to the corner store for something, and I barely made it there and back, once again bucking and stuttering like crazy. Put the uni back on, took her around the block, and it ran great. Your jetting and tuning of your carb is always done based on the airbox and exhaust installed (and other factors). If there is any change to either, it can cause problems with your a/f mix. After all, it's common knowledge you often have to upjet when installing a uni to compensate for the extra air being brought in. I would agree with you about alley being right , however I thought he was talking about a crack in the air intake tube causing this problem ? Not just weather u r using a uni or a stock air filter . If you tune the carb to match the airflow coming into the carb and it idles just fine , I would expect the scoot to idle the same at every light . whether its flexed and letting in more air it should still be the same at every light. Not constantly inconsistent. |
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Post by geh3333 on Jan 15, 2015 20:48:16 GMT -5
I use to have the same problem " at least with the scoot not idleing correctly until u take it for a ride , I actually posted something about that not that long ago " it ended up being a vacuum leak causing the problem .
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Post by JerryScript on Jan 15, 2015 20:53:59 GMT -5
A vacuum leak is the same thing, it's allowing in more air, as well as affecting whatever is vacuum actuated. In his case, the normally restrictive stock airbox is being bypassed, allowing in more air. This may not be the only problem, but it is a common problem with engines tuned to a restrictive air box. Those of us who have tuned our carbs with a uni hardly notice a difference with it on or off.
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Post by geh3333 on Jan 15, 2015 21:00:35 GMT -5
I went back and took a goog look at the pics again and noticed that they do not really show any noticeable oped cracks " at least in the pic ", there very well may be . I also went back and read the posts . I think some misunderstood rcq went he said I won't affect the air fuel ratio. Of course if u have an air filter or carack letting in extra air u may need to adjust the air fuel . what he and I were saying was since its before the carb it can be controlled just like having a less restrictive filter. If it were after the carb your going to be loosing suction through the carb ",completely bipassing the carb" and is harder to control. And with the cracks seemingly not that bad and there being not much flexing to open and close those cracks ",especially at idle " there should be no real change in the way it idles after tuning it in .
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..BAD TO THE BONE..
