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Mahinda123

Emission test report CO high.

Question

Hi Experts, 
Please advice and share your suggestions regarding emission test report failure.

I have aJapanese made Honda 250 motorbike. Past few years emission test passed without any failure but in this time Emission test was failed and showing CO rate as 4.35 for 2500 RPM. 
I don't use this motorbike frequently and from last emission test to this time done only 330 km

Last time emission test report showing CO 1.73 and this time showing 4.35, I cannot understand why such considerable change for 330 km. 
Air filter condition is good and replaced around one year before.

Thanks,  
Mahinda
 

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Probably the jet requires tuning. Air to Fuel ratio is supposed to be adjusted.

High concentrations of CO is due to an inadequate amount of air/oxygen for the given amount of fuel. Therefore adjustment could help to pass the VET.

Considering the case, clean the spark plug as well.

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Posted (edited)

was the carb tweeked by anyone?   Is the engine difficult to start, - check the ignition,..

Edited by Twin Turbo
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Simply not using a vehicle doesn't mean that it's going to perform well the next time you start it. Plenty of things can go wrong with a vehicle which has been left idle including rust in fuel tank, stuck carburettor mechanisms, dirty spark plugs and even moisture in engine oil. So I suggest you clean up that carb, spark plugs and make sure you do an oil change as well.

Before the emissions test, make sure you warm up that engine well. Cold engines run rich.

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Posted (edited)

Dear all, Thank you for your prompt reply. I really appreciate your suggestions.

Normally I don't give my motorbike to anyone for repairing, all repair and maintenance done by myself.  Today I just removed the carburetor for cleaning but carb condition is good. 

This carburetor with a small petrol pump with a diaphragm. For a fast accelerate more petrol injecting to engine and fuel mixture is too rich (For a slow accelerate this petrol injecting diaphragm doesn't work).  Today I just removed this mechanism (after removing small spring).  And taken back to emission test and PASSED…  CO value is 2.19

I saw previous day that guy accelerated very quickly more than 20 or 40 times. I guess, that was the reason for high CO rate.  But some guys at testing centers do this job professionally.

Spark plug not tested few years.  I have to check spark plug too.
One more thing, I removed all petrol too.. because bad smell like kerosene mix and filled 7 months before.  

Thanks,

Mahinda.

Edited by Mahinda123
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Posted (edited)
5 hours ago, Mahinda123 said:

I saw previous day that guy accelerated very quickly more than 20 or 40 times. I guess, that was the reason for high CO rate.  But some guys are at testing centers doing this job professionally.

Sadly this is true and the same thing has happened to me and a friend of mine who visited the same emissions testing centre where a worker raced the engine to about 5000 RPM like a maniac just before starting the test. My car with a carburettor engine failed the test (I had done all necessary maintenance and I even went to my local garage any got them to do an emissions test as well and passed).

I took my mechanic (also friend) there during the second time (later on the same day) and when he revved the engine, my mechanic gave him an earful and asked him to show where in the process it says that they should rev the engine that hard before the test. The manager of the testing centre got involved, and we requested that we idle the car for 10 minutes before starting the test. Surprise surprise, after doing no alterations, the car passed.

@Mahinda123, it might have been the same case for you. The diaphragm might have got stuck open for a while after the worker raced the engine. Anyway, glad you got it to pass. Well done. 

Edited by Davy
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17 hours ago, Mahinda123 said:

Dear all, Thank you for your prompt reply. I really appreciate your suggestions.

Normally I don't give my motorbike to anyone for repairing, all repair and maintenance done by myself.  Today I just removed the carburetor for cleaning but carb condition is good. 

This carburetor with a small petrol pump with a diaphragm. For a fast accelerate more petrol injecting to engine and fuel mixture is too rich (For a slow accelerate this petrol injecting diaphragm doesn't work).  Today I just removed this mechanism (after removing small spring).  And taken back to emission test and PASSED…  CO value is 2.19

I saw previous day that guy accelerated very quickly more than 20 or 40 times. I guess, that was the reason for high CO rate.  But some guys are at testing centers doing this job professionally.

Spark plug not tested few years.  I have to check spark plug too.
One more thing, I removed all petrol too.. because bad smell like kerosene mix and filled 7 months before.  

Thanks,

Mahinda.

As Davy mentioned, a warmed engine works efficiently.

Inefficient engines produce CO as the combustion byproduct.

@Mahinda123 Glad that you sorted out the problem with the DIY job. Hooray!

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17 hours ago, Davy said:

it might have been the same case for you. The diaphragm might have got stuck open for a while after the worker raced the engine.

Hi,

Thank you for reply again.

I just attached carburetor picture for your review.

According to report, for 2260RPM hydrocarbon (HC) values is 278, so I guess engine condition is good.

One more thing I forgot to mention,   year 2017 they had done some changes with CO and HC standard.

 New standard is, CO below 4 and HC below 6000 (before 2017 CO is 6 and HC is 9000)

Regards,

Mahinda

AcceleratorPump.png

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Speaking of Emissions tests,looks like a new gazette was issued to introduce JC08 test mode.

http://biz.adaderana.lk/වාහන-දුම-ගැන-නීති-අලුත්-වෙ/

 

If they do it right all test centres will need upgrades like Rollers and new Emissions equipment.

Also most of the diesel Trucks and buses wihtou EFI and Exhaust after-treatment  will fail..

Edited by ajm

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On 7/19/2018 at 3:13 AM, Davy said:

Sadly this is true and the same thing has happened to me and a friend of mine who visited the same emissions testing centre where a worker raced the engine to about 5000 RPM like a maniac just before starting the test. My car with a carburettor engine failed the test (I had done all necessary maintenance and I even went to my local garage any got them to do an emissions test as well and passed).

I took my mechanic (also friend) there during the second time (later on the same day) and when he revved the engine, my mechanic gave him an earful and asked him to show where in the process it says that they should rev the engine that hard before the test. The manager of the testing centre got involved, and we requested that we idle the car for 10 minutes before starting the test. Surprise surprise, after doing no alterations, the car passed.

@Mahinda123, it might have been the same case for you. The diaphragm might have got stuck open for a while after the worker raced the engine. Anyway, glad you got it to pass. Well done. 

This was the same case for Nissan N 16. Failed it several times  and did all sorts to get it fixed.  The bloody car does not have an oxygen sensor - thus the fuel mixing is done though a manual unit which does not change as per the ones which has an oxygen sensor. So once I left the engine running  for a short while, it passed.

This was explained to me by a mechanic who worked for [email protected] Mind you when I took the vehicle to [email protected] with the issue, their reply was that the car was manufactured in 2007 hence emissions  can fail.  

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On 7/19/2018 at 3:13 AM, Davy said:

Sadly this is true and the same thing has happened to me and a friend of mine who visited the same emissions testing centre where a worker raced the engine to about 5000 RPM like a maniac just before starting the test. My car with a carburettor engine failed the test (I had done all necessary maintenance and I even went to my local garage any got them to do an emissions test as well and passed).

I took my mechanic (also friend) there during the second time (later on the same day) and when he revved the engine, my mechanic gave him an earful and asked him to show where in the process it says that they should rev the engine that hard before the test. The manager of the testing centre got involved, and we requested that we idle the car for 10 minutes before starting the test. Surprise surprise, after doing no alterations, the car passed.

@Mahinda123, it might have been the same case for you. The diaphragm might have got stuck open for a while after the worker raced the engine. Anyway, glad you got it to pass. Well done. 

When I took the first emission test(when it was unregistered) for my Hiace I went to an emission testing joint which I usually do no go to. I noticed that the fellow who was carrying out the emission test was revving it even after the computer screen showed a message saying to release the accelerator. 

I guess some places do try fail the vehicle deliberately to earn some side bucks. 

Those of who are in kandy I can recommended the emission testing place on the Gohagoda Road. It's the first emission testing center on to your left just before that new bridge if you are going from Kandy. 

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On ‎8‎/‎13‎/‎2018 at 8:59 AM, ajm said:

Speaking of Emissions tests,looks like a new gazette was issued to introduce JC08 test mode.

http://biz.adaderana.lk/වාහන-දුම-ගැන-නීති-අලුත්-වෙ/

 

If they do it right all test centres will need upgrades like Rollers and new Emissions equipment.

Also most of the diesel Trucks and buses wihtou EFI and Exhaust after-treatment  will fail..

CO AND NOx measurements? are You kidding? We are talking about a country where bus and truck drivers mix kerosene 50/50 in order to cheat on the emissions test where mostly Particles Matter are checked(it is the final but 100% working solution invented by garage baas)

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