Author Topic: carburetor question  (Read 10010 times)

csor.zola

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carburetor question
« on: May 16, 2014, 08:03:53 AM »
Hi everyone,
 
I have got a kymco 125 agility. I took off the carburetor to clean it and to inspect it more closely because at the moment it won't start. It fires up for a second couple of times but then nothing. I bought it like this yesterday. I checked the fuel system and the carburetor has plenty petrol. I took out the spark plug and it works perfectly and was fully wet with petrol. (Maybe too much) So, I took off the whole carb give a good clean. But surprisingly it was not bad at all. (The scooter has only 5000 km and 1 year old). I set the pilot screw, 2 and half turn. I don't know the position of idle screw. I gonna play with it. Or anyone knows?
Now I took off the auto bystarter and gonna check its resistance. The manual says it should be under 10ohm.
I checked the air filter. Nothing special. It is a bit wet of petrol. But I think it's normal.
BUT....
I found something on the carb. It is a some sort of electric part  close to the engine site connected to the butterfly valves next to the bystarter and in front of the pilot screw. I have tried to attach a picture of it but Itoo large. Does anyone know what is this and how to test it if it works? Could it be my problem?
If the bystarter will be fine I going to check the valve clearance.
Or Any advice what I can check?

tortoise

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Re: carburetor question
« Reply #1 on: May 16, 2014, 01:20:42 PM »
I found something on the carb. It is a some sort of electric part close to the engine site connected to the butterfly valves next to the bystarter and in front of the pilot screw.
TPS (Throttle Position Sensor) . . similar wiring diagram

csor.zola

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Re: carburetor question
« Reply #2 on: May 16, 2014, 04:19:20 PM »
Thanks.
Been looking around I have seen that the most gy6 carb does not have that  tps installed. Interesting....
Anyway
I measured the resistance of the by starter 13-14 ohm. According to the manual it should be changed. But the funny thing is that easier to buy a whole carburetor than the bystarter only.
But luckily I managed to start the engine after all. The main problem was the spark plug. It did not give a strong spark and when I checked it properly I saw that spark is reddish and is not between that two thing. So, I changed it and woala...starts. But not easily. I have to pull the throttle to get the engine started. But at least it starts.

tortoise

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Re: carburetor question
« Reply #3 on: May 16, 2014, 06:09:36 PM »
Definitely check valve clearance and cylinder compression!  If no joy, there may be an intermittent spark issue.  Check stator, pulser, and ignition coil Ohms.  If still no joy, the DC-CDI may be the gremlin.

csor.zola

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Re: carburetor question
« Reply #4 on: May 17, 2014, 03:22:59 PM »
I am still looking for a carb with tps but I have not seen any. Or am I blind?
 They have only a brass cap inplace of the sensor. Is my one special or just that sensor needs to be transferred? Or any gy6 carb will do for me?

CROSSBOLT

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Re: carburetor question
« Reply #5 on: May 17, 2014, 03:30:18 PM »
Why would there be a TPS on a carb? TPS is for fuel injected systems.

Karl
Karl

Three motorcycles 1960-1977 (restored a 1955 BSA)
Agility 50
Yager 200i
Downtown 300i
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csor.zola

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Re: carburetor question
« Reply #6 on: May 17, 2014, 03:38:59 PM »
Well...ask who made my bike. Or someone told me incorrectly. But if you read my first post I ask a question about some electric part on my carb. I did not know what is that and I was told that is the tps.
But I am quite sure that is a tps. And since then I am looking for a same carb like mine unsuccessfully.
....
I have a question. Most of the gy6 carb has a brass cap next to the auto choke where my tps or I do not know how to call it is. Is that cap removable?? Can I put my tps in place of it?

CROSSBOLT

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Re: carburetor question
« Reply #7 on: May 17, 2014, 10:31:14 PM »
No, czor, it was tortise that suggested it was a TPS. Carbs seem to have the auto bystarter and fuel injection seem to have the TPS and ISC(idle speed control). There is no reason to mix them. I do NOT know what the electrical thingy is on your carb near the bystarter. A picture run thru Photobucket would help. A service manual would help also: MAYBE ONE OF THE FORUM GANG HAS A COPY ON HIS COMPUTER HE COULD SHARE WITH YOU. HINT HINT!

Karl

Karl

Three motorcycles 1960-1977 (restored a 1955 BSA)
Agility 50
Yager 200i
Downtown 300i
Navy tech, Ships Engineer, pilot and aircraft mechanic

zombie

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Re: carburetor question
« Reply #8 on: May 17, 2014, 10:50:26 PM »
Re-size the picture with Paint. Right click the image, and you will see Edit. Click that, and paint will open with an option to Re-size on the top left.

Since you have to crack the throttle that tells me you are indeed rich. You can remove the Bystart, and see if it moves the pin when you turn on the key. It tales about 90 seconds for the pin to extend about 4mm. If it does not extend that is the entire issue.

Automatic Enricher Operation (10x Speed) : Choke Bypass Bystarter
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

csor.zola

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Re: carburetor question
« Reply #9 on: May 17, 2014, 11:04:24 PM »
Here we come....so, I have already taken off the auto choke. But next to it between my two fingers there is an electric device. I plaged the cable out. Once I took it off from the carb to see what it is and it connected to the butterfly shaft. Inside it has a spring. You can't see it but you can feel it as you turn it. Only one screw hold it. It can't be seen from this angle but the screw has some kind of groove to move in. So you can turn the whole device until a curtain point.
I was thinking maybe I put it back incorrectly that is why hard to start .

So...what do you think? What is this. I think is the tps
« Last Edit: May 17, 2014, 11:43:22 PM by csor.zola »

zombie

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Re: carburetor question
« Reply #10 on: May 17, 2014, 11:19:17 PM »
That is a throttle position sensor, and it does require an EXACT setting. You need to locate the service manual to find the procedure. There is also a procedure that calibrates the sensor/computer once it is adjusted correctly.   

kymco downtown 300i reset

You need to find the voltage setting first. It is usually 0.5 volts out on most engines but I am not sure for the 125 Kymco

KTM Throttle Position Sensor (TPS) Adjustment Made Easy - Special Tool
« Last Edit: May 18, 2014, 02:21:23 AM by zombie »
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

csor.zola

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Re: carburetor question
« Reply #11 on: May 17, 2014, 11:26:49 PM »
Bloody hell...It does not sound good. So, if I turn this thing it will change the voltage?
And why I can't find same carb at all? What if I just replace it with a normal gy6 carb?
And anyway....why you two are not sleeping yet?

csor.zola

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Re: carburetor question
« Reply #12 on: May 17, 2014, 11:40:53 PM »
I have checked the manual that I got. Its headlight says agility 125 but picture of the carb in it not the same with mine. It does not have the tps and the whole book does not mention it at all. I am having a bit difficulty. If you find something about the exact voltage please let me know.
Thanks in advance
Zol

csor.zola

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Re: carburetor question
« Reply #13 on: May 17, 2014, 11:45:04 PM »
And one more question. What is the purpose of this tps? Why mine has it and others does not

zombie

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Re: carburetor question
« Reply #14 on: May 18, 2014, 02:20:54 AM »
Throttle position sensor. It tells the computer exactly where the throttle is, and how much fuel to supply and or what the Ignition timing is supposed to be. I would suggest you use a DVM, and set the initial voltage to .5 volts. See how that goes.

Just buy the nw choke if the carb is good.
 
http://www.ebay.com/sch/i.html?_trksid=p2050601.m570.l1313.TR0.TRC0.H0.Xgy6+auto+choke&_nkw=gy6+auto+choke&_sacat=0&_from=R40
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

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