foxy
Regular
Posts: 14
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Post by foxy on Oct 24, 2005 12:56:25 GMT
On my baotian i have a pipe that runs from my exhaust to my air intake. Havent known what this was since i purchased the bike last october and a couple of weeks back i just took it off to see what difference it would make. I noticed the only difference at the time was sound. Ive been running about without it on for a few weeks and recently went to change the feul setting on the pin in the carb. Whilst putting the cover back on i broke the diaphram seal (Think thats what its called) and then my bike was going along at about 10mph. So i ordered a new one fitted it etc but there was no difference. After hours of experimenting with different things, cleaning out the carb etc i decided id just put that pipe back on. Since doing this my bike has krept back upto 30-40 mph. However it is not as quick top speed/acceleration as what it used to be.
So what does that pipe do? Why didnt i need it before yet do now?
Sorry for the mass ammount of data but i thought if i gave you the whole senirio you might be able to make something of it.
Thanks alot
Nicholas Fox
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foxy
Regular
Posts: 14
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Post by foxy on Oct 24, 2005 13:16:27 GMT
forgot to mention when i took the pipe off i also took the tube to the airfilter out so just had to air going directly into the box rather than through the pipe then into the box. I added the mysterious tube into the air filter and it made my bike choke. However since me tampering with the bike it has the opposite effect where it chokes without it!!
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Post by Gavin on Oct 24, 2005 14:30:29 GMT
forgot to mention when i took the pipe off i also took the tube to the airfilter out so just had to air going directly into the box rather than through the pipe then into the box. I added the mysterious tube into the air filter and it made my bike choke. However since me tampering with the bike it has the opposite effect where it chokes without it!! Please don't read the post about gluing rubber bungs to the tyres  |
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Post by Badobsession (the real one) on Oct 24, 2005 20:25:56 GMT
When you put everything back how it was did you put the clip on the needle back to the original position?
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foxy
Regular
Posts: 14
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Post by foxy on Oct 25, 2005 8:58:02 GMT
Yeh tried that, i put it all exxactly how it was. But no difference. Is there anything i could have knocked out of place or something?
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Post by Badobsession (the real one) on Oct 25, 2005 20:34:16 GMT
Not got a chinese scoot anymore so not sure about the pipe, maybe someone else can help you?
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foxy
Regular
Posts: 14
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Post by foxy on Oct 25, 2005 22:57:14 GMT
ok thanks anyway
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Post by chcknugget on Oct 26, 2005 2:14:19 GMT
Could you post a picture of the pipe? Is it chrome? I'm very interested in this topic, because I have a pipe coming from the exhaust but it was blocked off from the factory. Is this it? |
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foxy
Regular
Posts: 14
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Post by foxy on Oct 28, 2005 0:10:50 GMT
nope, its located just in front of the actual exhaust box. There is a little metal (1cm in diameter) bi pass sort of thing which then goes into a little box and then has a rubber pipe leading to the air filter box. I cant see it having any use what so ever, just seems to be putting the nuts from the exhaust back into the engine... Yet it wont run without it in?!
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Post by Gavin on Oct 28, 2005 8:30:34 GMT
nope, its located just in front of the actual exhaust box. There is a little metal (1cm in diameter) bi pass sort of thing which then goes into a little box and then has a rubber pipe leading to the air filter box. I cant see it having any use what so ever, just seems to be putting the nuts from the exhaust back into the engine... Yet it wont run without it in?! In the parts list, the 'little box' is called a control valve, (Part No. BT50QT-120300), so it must control something. Just a guess here, but it might be to stop the scooter running if the exhaust is removed, or modified, i.e. if there is no back pressure from the exhaust, the scooter will not run. |
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Post by Botanic on Oct 28, 2005 19:38:56 GMT
I think that the thing you are talking about is the air cleaner thingie. It has a proper name that I have forgotten. It is a valve that takes air from the airbox into the exhaust. This is all it does.
By adding some air to the exhaust pipe, the temperature rises inside the pipe, which burns some of the unburnt petrol.
The enviroment likes this.
The only function that this pipe has is for making the exhaust cleaner. It should not affect the performance in any way, as long as the valve is working.
The valve can break down and blow exhaust into the airbox. This makes the engine run badly.
If you unplug the pipe that goes into the airbox, it will sound more. If you plug the pipe with something (M5 screw for example), you will blow more exhaust into the environment.
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foxy
Regular
Posts: 14
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Post by foxy on Oct 29, 2005 12:19:04 GMT
but if i take the pipe away from the airbox, or seal it my bike just chokes ?!?!
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Post by Gavin on Oct 29, 2005 13:49:05 GMT
I think that the thing you are talking about is the air cleaner thingie. It has a proper name that I have forgotten. It is a valve that takes air from the airbox into the exhaust. This is all it does. By adding some air to the exhaust pipe, the temperature rises inside the pipe, which burns some of the unburnt petrol. The enviroment likes this. Then why have the pipe going to the airbox? Surely it would be easier to just take fresh air from the valve inlet, and introduce it to the exhaust, also wouldn't adding cold air to the exhaust pipe decrease the temperature of the exhaust gas, not increase it? The bit about burning off unburnt petrol in the exhaust pipe also sounds unconvincing, but I am not up on catalytic converters, so I am up for persuasion about this |
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Post by Gavin on Oct 29, 2005 16:47:34 GMT
Right, after months of painstaking research  I have found the following about catalytic converters. Some types of these are fed from an air pump, which pumps air into the catalytic converter, the compressed air provides increased oxygen, which helps burn any unused fuel, so presumably in the case of scooters, the airbox acts as a pump by compressing the incoming air. Now unconfirmed theory, (well a wild guess) from me as to why removing the mystery pipe might affect performance. Presumably any unburnt fuel will clog up the converter, and block the exhaust, then when the pipe is refitted, the blockage is reduced as the increased oxygen helps clear it by burning away any residue. As I said, this is just a wild guess, so any other takers? Details of what I found about catalytic converters here:- www.meineke.com/services/catalytic.asp |
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Post by Botanic on Oct 29, 2005 18:53:04 GMT
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Post by hypojam on Oct 29, 2005 20:51:16 GMT
These bikes are way too cheap and simple to have a catalytic converter!  |
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Post by Gavin on Oct 29, 2005 21:37:20 GMT
These bikes are way too cheap and simple to have a catalytic converter! Have you seen the recommended retail price of the exhaust systems |
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Post by Botanic on Oct 30, 2005 15:41:35 GMT
I wouldn't call this a catalytic converter. It is just air into the exhaust pipe. The oxygen burns the unburnt petrol.
There are models (TWS Panda for example) that has a catalythic net inside the exhaust pipe. When the exhaust gases travel through this net, they get cleaner.
A very simple construction.
Since it brakes the exhausts on their way out, it steals some effect.
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I have found the following about catalytic converters. Some types of these are fed from an air pump, which pumps air into the catalytic converter, the compressed air provides increased oxygen, which helps burn any unused fuel, so presumably in the case of scooters, the airbox acts as a pump by compressing the incoming air.
