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Post by HotStuff2 on Apr 21, 2012 7:14:46 GMT -5
So, as someone else posted that they were planning to remove the EGR and block it off, I'm thinking of doing this as well. What would be the advantages/disadvantages to doing so? As I understand it, the GY6 engine uses a very basic EGR system, and uses anywhere from 10% to 30% vacuum to perform it. From reading about EGR, if the system is designed for the engine, it can be beneficial, but it looks like the EGR system put in place on the GY6 is a generic system slapped on to help the engine meet CA emissions standards. Thoughts? Opinions?
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Post by Saber on Apr 21, 2012 11:21:47 GMT -5
I wish someone could throw some light on the subject of blocking off the PAIR system.
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Post by HotStuff2 on Apr 21, 2012 16:30:45 GMT -5
What is the PAIR system?
edit: Hmmm...apparently, what I thought was the EGR is actually the PAIR system. From ChineseScooterReference.com:
"It stands for Pulsed Air Injection Reburn. It sends pulses of fresh air into the exhaust during low pressure pulses in the exhaust side. This is a canister that has a vacuum line and a hose to the valve cover area. It is usually only on newer scooters. This helps burn uncombusted gases that make it through the engine."
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Post by Saber on Apr 21, 2012 20:54:09 GMT -5
What is the PAIR system? edit: Hmmm...apparently, what I thought was the EGR is actually the PAIR system. From ChineseScooterReference.com: "It stands for Pulsed Air Injection Reburn. It sends pulses of fresh air into the exhaust during low pressure pulses in the exhaust side. This is a canister that has a vacuum line and a hose to the valve cover area. It is usually only on newer scooters. This helps burn uncombusted gases that make it through the engine." Yeah so what's the benefit if any of blocking this off?
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Post by HotStuff2 on Apr 22, 2012 6:04:50 GMT -5
The Wikipedia article on EGR seems to indicate that it could reduce throttling losses, reduced heat rejection, reduced chemical dissociation, but also decrease the efficiency of gasoline engines via at least one more mechanism, reduced specific heat ratio. (A lean intake charge has a higher specific heat ratio than an EGR mixture. A reduction of specific heat ratio reduces the amount of energy that can be extracted by the piston.) But according to another user: So, the question I'm wondering now: is the EGR system the same as the PAIR system?
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Post by jogi on Apr 22, 2012 6:27:40 GMT -5
So, the question I'm wondering now: is the EGR system the same as the PAIR system? No, PAIR add air to exhaust to help catalyst converter to burn excess unburned mixture and EGR recirculates little bit "inert" exhaust gas to intake stream to reduce some "pollution" and lowers pumpping losses from engine (not much but little, in bigger engines -> cars..) Gy6 engines usually use just PAIR.. it does not rob engine power and may keep exhaust gasses little cleaner (less smell ) so no real reason to block it off.
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Post by HotStuff2 on Apr 22, 2012 7:43:39 GMT -5
Interesting. How can I tell the difference? From the description thus far, I'm pretty sure the Taotao uses a PAIR system, but I'd like to know for sure.
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Post by jogi on Apr 22, 2012 14:30:43 GMT -5
If it's valvecover/head is like this -> www.partsforscooters.com/core/media/media.nl?id=13874&c=ACCT120207&h=634b27dbbbe36c4cc7a3 it is PAIR... actually I have not see any EGR versions in these engines.. many times GY6 PAIR is identified as EGR but it is just mistake.. air moves to exhaust and not otherway around. If PAIR breaks then it is possible that exhaust gas goes in wrong direction and might create confusion about what it is. 50cc engines sometimes use PAIR valve system attached to exhaust pipe..
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Post by mainepeace on Apr 22, 2012 18:00:11 GMT -5
Some scooters have actual EGR systems. Most of those are older ones though. Most are PAIR incorrectly identified as EGR as jogi said.
Greg
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Post by HotStuff2 on Apr 22, 2012 19:42:24 GMT -5
Yes, that is what I have - thus, it is PAIR, not EGR.
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Post by Blueboy5000 on Apr 24, 2012 7:44:17 GMT -5
I just removed the PAIR system and man what a difference! My bike actually runs without vacuum starvation now. It's nice to be able to hit rpms higher than 5000. I also replaced the non adjustable carb with a Keinhin 24mm. My bike is definitely running much better and is no longer hesitating.
I would recommend this be done to any GY6 as long as it's not illegal to do so where you live. Your bike will thank you.
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Post by qwertydude on Apr 24, 2012 10:18:28 GMT -5
The PAIR system can be made to work without using vacuum. Some of the more complex smog systems like on Piaggio's use a weird vacuum regulated valve that shuts off the PAIR system at high RPM to preserve power since adding cold air to the exhaust stream can slow exhaust velocity due to added mass and lowered exhaust temperature. Generally the PAIR system isn't needed at higher speeds because the engine will be naturally burning its fuel better due to higher overall combustion chamber pressures effectively burning all excess fuel.
Now I say it can be made to run without vacuum and shut off at high RPM's naturally because the reed valve system can be tuned to exclude high frequency pulses, this is the reason for the long chrome vent tube. It needs to be a certain length to act as a low pass frequency filter. The GY6 uses this system. Why doesn't the Piaggio? Piaggio wanted to put out their own patent, there's just happens to be, like most Italian systems, overly complex and high maintenance.
You can get a better running PAIR system by isolating the vacuum lines that run the PAIR system from the ones that run the fuel system. Generally it works better because you don't want to be using so many T-splitters on the vacuum lines especially if your fuel system needs a vacuum fuel pump. On my 150cc scooters I simply isolated the fuel pump vacuum and switched the PAIR and canister vacuum lines to one of the other vacuum nipples on the intake.
Then again I eventually ripped it out because inevitably I overfilled the gas tank, when you do that, the charcoal canister floods and the scooter will be very hard to start and run erratically. But one of the disadvantages to removing it would be if you have a catalyst, at low rpms it needs the extra air to burn the excess fuel, without it you might get a carbon build up. A disadvantage to keeping it, and this only applies to our scooters with the vent right next to the exhaust valve, would be if you're running really rich, the excess air can cause the excess fuel to ignite near the valve, and constant running like that can burn the exhaust valve.
Personally even in California everybody removes it, on a carbureted bike they can cause so much trouble if not perfectly engineered. About the only one that didn't give me trouble was on my a GS500F. Even my Honda Rebel I had to desmog because the canister and valving malfunctioned causing difficult starts and erratic running.
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Post by HotStuff2 on Apr 24, 2012 10:33:25 GMT -5
I just removed the PAIR system and man what a difference! My bike actually runs without vacuum starvation now. It's nice to be able to hit rpms higher than 5000. I also replaced the non adjustable carb with a Keinhin 24mm. My bike is definitely running much better and is no longer hesitating. I would recommend this be done to any GY6 as long as it's not illegal to do so where you live. Your bike will thank you. How can you tell if you're experiencing vacuum starvation? I have to get a tach installed so I can see what RPMs I'm hitting.
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Post by chromestarhustler on Apr 24, 2012 11:14:59 GMT -5
pair steals a small part of the intake charge pulse to inject into the exhaust to re"burn" the exhaust for cleaner emissions, if you service you bike normally, the system is in the way. makes removing the exhaust more difficult, just ever so slightly, just like the poorly designed vent system, pull it rework it correctly and dont worry about it.
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Post by Blueboy5000 on Apr 24, 2012 13:13:02 GMT -5
I found out it had vacuum starvation by first isolating all vacuum lines. That wasn't difficult because there was only three, one to carb diaphragm, one to fuel pump, and one to a large vacuum solenoid switch valve connected to the hose to the PAIR.
I then installed 3/16 fuel hose as replacement for original China hoses. I installed a clear bodied fuel filter to observe fuel flow while engine was running. Tached up, found good fuel flow until 5000 rpm. Filter could not keep up with engine over 5000 rpm. So I used a hand vacuum pump to test the petcock. Petcock was fine. I checked all the vacuum lines and actually replaced them all with new hoses. Then I ran it and tested for leaks with propane on all vacuum ports and hoses as well as the carb and intake.
Then I removed the PAIR, installed block off plate and Keinhen 24mm carb. Bike no longer hesitates and fuel filter no longer runs dry. Also, bike is much snappier and a bit faster. I do not know my top speed atm since it only has 200 miles on it and I am easy breaking it in, but it accelerates much more smoothly.
I personally believe these no adjustment carbs and cheapo PAIR systems to be poor engineering.
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Post by larrball on Apr 24, 2012 13:57:05 GMT -5
This is a PAIR system on my scooter if it helps anyone to see a pic. It runs up too the air box. Side note: Taking off the hose off the PAIR valve will drown out most all rap music your Neighbors can muster out of there crappy a$$ beat up, oil smoking caddy that still has yet had a tune-up in the last 20 years. /rant Just FYI.
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Post by HotStuff2 on Apr 24, 2012 16:28:46 GMT -5
My scooter doesn't have that...
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Post by lee47848 on Apr 24, 2012 18:33:39 GMT -5
mine is a 2012 it doesn't have that.must be a cali thing.
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Post by timelancer on Apr 24, 2012 21:30:39 GMT -5
it just depends on the scoot you get, some have them some don't my rocketa had it. It was causing fuel starvation from day one. not sure what it does in term of vampiring vacuum but i do know that it can and will prevent the petcock valve from opening completely thus not allowing all the fuel to get to the carb. I have also heard of them causing fires or burnt out exhaust valves. Based on this info I decided that I would put in a CDI perf. coil and Iridium spark plug to make the exaust cleaner, and get some more power too without the risk of my powerrplant setting on fire over a chinese piece of S***. just my 2 cents.
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Post by orphansoul on Apr 24, 2012 21:33:17 GMT -5
My only gripe is that if you only have one vacuum nipple on your manifold, the system will inevitably cause a vapor lock. Never had the issue when I had a manifold with 2. But the larger one I upgraded to has 1, and I have been getting shut down from fuel vapors every other day. Finally unhooked the system today, got fed up with having to drain fluid/vapor out of the vacuum lines.
Edit: I just drove mine around post disabling the system. Drives a lot better, much smoother. No locking up from vapors.
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Post by jogi on Apr 25, 2012 1:49:55 GMT -5
My understanding is that PAIR itself is not related to vacuum issues, as it just gets fresh air from own source or from air cleaner so it does not rob vacuum. And blocking off PAIR _AND_ changing carb does not mean that PAIR was the bad boy. But yes, if PAIR brokes it causes problems. Secondly vacuum operated petcock is bit weird, it usually gets good vacuum but throttle wide open causes vacuum to drop near zero so it is bit mystery that petcock even works.. no wonder it can cause problems (for example open style air filter makes vacuum even lower)
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Post by Blueboy5000 on Apr 25, 2012 6:44:14 GMT -5
Nope that's not what I removed. I removed the metal 3/4 inch tube that is mounted to the head and runs over the valve cover to a rubber hose that runs to a solenoid that is connected to another rubber hose that is connected to the exhaust pipe. The solenoid itself is a two inch long by 1 inch diameter cylinder ported to it's own port on the intake manifoid (there is two ports). The solenoid was clearly a vacuum activated switch.
Being an automotive technician, when I see a steel line that runs from the head to the exhaust via a vacuum solenoid valve, I tend to think it's an Exhaust Gas Recirculator. So I figured it was an EGR. It is clearly a vacuum operated valve of considerable size.
Whatever it is I removed, the NCY kit was simply called and "emissions block-off plate kit."
I am rather confused as to why there is so much debate as to rather or not this system is effective. If dumping high rpm vacuum to this mysterious solenoid causes vacuum to decrease to the petcock to the point of fuel starvation, then the system is clearly 1) defective or 2) a poor design.
Regardless, my 2008 Wildfire and 2008 Sunl do not have this emissions system at all. No emissions of any kind. It became logical to assume the system was unnecessary. Plus the carb was slugged. After removal of the system and replacement of the carb, the bike (a 2011 Baccio) runs excellent. It even appears to be able to easily hit 60+ mph now.
Lastly yes it does mean this emissions system was the problem. According to my vacuum gauge, the engine is producing the exact same amount of vacuum with the new carb as it was with the old one at all ranges of RPM.
It should be noted that I did not change the carb to remedy my fuel/vacuum starvation issue, but rather because it was a non-adjustable Bashu carb. It is completely impossible for a slugged carb to be set to the correct air/fuel ratio everywhere in the world on every engine of every age. In fact, the assumption that the slugged carb is capable of such operation is completely false. No carb is automatically adjustable to the degrees needed to vary their mixtures in relation to things like elevation, humidity, engine age, type of engine ect.
So it is rather moot as to whether or not a carb was necessary. And the emissions was starving the bike's vacuum at RPM's over 5000. Thus emissions had to go, and a new carb became installed.
The bike runs awesome now. I generally consider repairs made with controlled analysis of a problem that succeed, to be success.
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Post by HotStuff2 on Apr 25, 2012 10:25:42 GMT -5
I don't have a petcock; my Taotao uses a fuel pump.
Still, I think I will remove this. I should just be able to put a cover on the nipple(s), no? I saw nipple caps in the auto store, and they should work...
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Post by Blueboy5000 on Apr 25, 2012 11:38:39 GMT -5
I don't have a petcock; my Taotao uses a fuel pump. Still, I think I will remove this. I should just be able to put a cover on the nipple(s), no? I saw nipple caps in the auto store, and they should work... Yep. That's what I did. I capped the vacuum port on the manifold with a 3/16" vacuum cap. It is very good that you have an electric fuel pump. They provide much more consistent fuel flow.
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