Disconnecting GY6 Emissions? By bigkahuna427 (Read 26,172 times)

[bigkahuna427]

I have seen some examples here and on other forums of people who are recommending disconnecting PAAR and crankcase vent systems. One of my scoots is a 50cc GY6 Peace and in looking at these systems I find them to really be harmless from a performance aspect. In fact disconnecting them without other modifications would probably hurt performance. I am not talking about replacing exhaust and air box modifications or re-jetting a carb.

Can anyone tell me how just alone disconnecting these things would actually improve performance?

[Bashan]

Well you would never want to remove your crankcase breather, the hose off of your valve cover, it's vital to the engine function. I took the vapor canister off of my Motorino because it was cutting off the gas tank venting. That will definately hinder performance ala stopping the engine. The PAIR system works post exhaust port so yeah, that's not going to affect the performance. However, I did take that off of my Motorino, and all of my other GY6s come to think of it, because I felt it junked up the engine compartment and was a potential source of vacuum leaks. There have been some bizarre pollution devices show up on the forum that plugged into the intake manifold and those DID hinder performance. In fact, one of the dealers said they routinely remove those varieties all the time. Here is a picture I found of one of them:

So if you have a pollution device that plugs into your system before the intake port then yes it can affect the performance of the engine. Anything on the exhaust side shouldn't affect the function of the engine. That's my opinion, some other guys might feel differently. Rich

[jct842]

I think the best reason to remove is prevention. with all the possibility's of leaks and the poor rubber hoses and the manifold eliminating a few makes sense to me. the KISS principle. those engines vibrate nicely and to knock just one hose loose is not hard. john

[bigkahuna427]

I have seen thus far people disconnecting three systems.
Carbon Canister:
This is evaporative emissions. It simply stores fuel vapor that comes off the tank and perhaps the carb bowl as well. It then takes these vapors and introduces them into the intake to be burned.
Crankcase Vent:
Is basically a vent system for the crankcase and takes blow by off the crank case. Blow by contains raw fuel that has leaked past the rings and also combustion gases that also contain hydrocarbons or raw fuel.
My point here is that these engines are probably on the hairy edge of being too lean but they are engineered to be right at the best performance and milage and the fuel air ratio is dialed right in. These now disconnected systems were in the equation of that balance of fuel and air. Now you could just re-jet the carb but I question whether many folks doing this is really all that accurate. Reading plugs there really is not all that much difference between 9:1 and 15:1 and in any of these ranges the performance is fairly similar. Reading a plug is really a crude way to judge mixture.

Paar system:
This introduces a bit of air into the exhaust. It is not to dilute the exhaust. Air includes oxygen and oxygen is an accelerant. You need oxygen for a wood stove you need oxygen for a oxy acetylene torch. Introducing oxygen into your exhaust provides an accelerant for the unburned fuel in the exhaust. Providing oxygen for the catalytic converter makes the converter heat up better and more efficient at burning un-burnt fuels. Don't care how well your converter works? You should care. Most converters are monolythic style with long very small passages. If it doesn't heat up enough it could start to collect carbon and soot and start to plug. Plugged or restricted exhaust would certainly detract cause poor performance.

Perhaps disconnecting these things is more trouble than it is worth?

[Alleyoop]

The Paar system i agree with you could leave that on BUT they eventually will leak.

The Canister is a different story all together, you will find that sooner not later you will see gas hopefully on the floor and not on a hot part of the motor or exhaust. They tend to suck gas through the hose if you fill the tank up to much or even when riding and going over rough terrian or bumps or holes the gas splashs around in the tank and goes out the Vent hose to the canister. Then you have problems with how the engine runs.

Best solution is disconnect the Tank Vent line going to it and plug up the Vacuum line also going to it and put a fuel filter on the end of the Vent Hose and tie it up high on the frame.
If you have the hose setup to be above the tank you will not experience gas being squirted out or dripping out on to something that might cause a fire.
Alleyoop

[bigkahuna427]

So it seems that disconnecting the carbon canister has it's concerns too. Why not fix the system? I haven't seen the issue you are talking about but seen the system. My guess is a few of them have done it so the common advise becomes, it's emission junk rip it off and throw it away. Why not put a loop in the hose between the tank and the carbon canister as a cure. Heck I would probably do that if I had the hose vented to atmosphere to keep the gas from spilling onto the floor, exhaust etc.

[Bashan]

I have a couple comments. First of all, it's true that if you have a catalytic converter in the muffler it could get clogged up just like they do in cars. The classic diagram of the PAIR system shows a converter in the system:

However, I talked to several dealers that said most of the mufflers, especially on earlier, and cheaper, scooters don't have converters. The system is one of the Chinese "see, we're trying" methods of getting bikes in the country past the EPA. So the system in these cases supposedly uses the pulses of outside air to burn up uncombusted fuel in the muffler; very inefficient at best.

In regards to the vapor canister, a loop in the line would work if it was vertically oriented and high enough to drain back into the tank. I suggested this a few times on the forum and the response was that they didn't have enough room under the plastic. Orienting a vent line just slightly upwards without the canister will keep gas fumes out of the garage since they're heavier than air. Of course tipping the bike over would indeed cause a spill. They do make one way vented caps and vent tubes now that would prevent that. That might make the EPA happy too by keeping the fumes out of the air. Rich

[bigkahuna427]

Even in Mufflers without the cat then the air introduced into the exhaust at the exhaust port would "light off" unburned fuels from the combustion process. I suspect a system with a cat would be different than a system without. These are really very simple systems and once understood could easily be repaired. I think the general attitude though is "you don't need it rip it off". I believe this can create other issues that the person ripping it off won't comprehend.

[kz1000st]

The problem I had with my PAIR system originally was a secondary valve that stuck open and made the system run lean. A simple bolt in the hose attached to it solved the problem. As with all the components on Chinese scooters you have to worry about bad materials creating problems that are hard to track. I've watched people advise carb adjustments when I think the problem sounds electrical. Even recent issues with my intake manifold involved the cheap o-ring leaking. Why not just a fiber gasket?

I think people take the path of least resistance and just remove the offending items before those parts bite them, for better or worse. In most instances it only seems the scooter is running better because the parts removed were already beginning to fail. My scooter ran better than new once I plugged the valve off. I imagine the valve was slightly defective to start with and finally gave up after 500 miles.

[89newbie]

This thread reminds me of all the stuff we went through on the mid 70 to the mid 80's cars. I think the requirements are so loop holed the manufacturers do what they can to comply but face it how much emissions can a little 50 or 150 emit? I remember the 302 1978 Mustang with 4 speed was exempt from a cat and actually had that on the sticker the MFG. glued to the valve cover. That combination had nothing except a fuel canister for fumes and a PVC. The v-6 had all the emissions junk you could imagine for the same year. Its a game we all have to jump through the hoop on, and if we can eliminate the loop we are better off. My wildfire has the old style valve cover and have had no problems. The ice bear 50 has all the crap and Im ready to junk that its such a pain in the butt! The JCL 150 has the emissions and while a vent for the engine is fine dont think it needs to go where it is going!

[bigkahuna427]

The fact that you "ripped off" a system not knowing how it worked or the benefit of it with no gain in performance illustrates my point. It is a common theme amongst the shade tree mechanics in the auto world. The effect of removing this system is that your scooter now dumps 50 to 100 times more pollutants than a scooter with this system left intact. Also, the converter will not work as designed and could get restricted actually causing a performance decrease when you had hoped for a gain.

No China man is going to spend a single cent on something that does not reduce pollutants. These systems work and have proven themselves in reducing emissions without affecting performance. Keep in mind performance and emissions go hand in hand and is a bit of a balancing act. The better an engine runs and the closer it is to the ideal 14.7:1 fuel air ratio the less exhaust emissions it would need. Really these systems clean up an inefficient dirty engine by burning what is left of unburned fuels in the exhaust.

Diluting the exhaust is not the purpose of the PAAR system. It is introducing a small amount of air to excite or accelerate the burning process that is already occuring in the exhaust pipe near the exhaust valve.

Anything that introduces exhaust into the intake I know as an EGR. This is another commonly misunderstood system. It is NOT there to re-burn exhaust gasses as many people do think. The amount being metered is so small that I can see how people would think this is another useless system. It's effect on emissions is to reduce NOX.

It's performance BENEFIT is it reduces combustion temps and pre-detonation or ping. Pre-detonation or ping IS a performance deficit. It is a quick flash off or quick burn of the fuel air charge in the cylinder. What you want is a controlled burn and an expansion that occurs at the ideal crank position and for a good portion of the down stroke. Because designs that use EGR run more advanced timing curves the effect of a not working EGR is ping. So for the person that does disconnect that system they have created a problem. The next thing they do is retard the ignition to cure ping which is another performance deficit.

[scooter12]

I have had others tell me to remove the canister and plug up the emissions system. That it would not hurt it, but I did not do that.. The canister looked as if it had caught fire on my Bali 250.. I could not find the part no where on the Roketa site, so I bought a simular type filter system at Oriely Auto Parts Store. The canister is really a filter system that connected to the EGR that connects to muffler. But mine has run fine and not got hot..

Now I have been doing some thinking on scooters in general. The 89 octane I used for nearly a year, might have caused the canister to catch fire or melt. 89 octane sparks easier than 90 octane gas. Another thought on octane is 91 octane is 100% pure gasoline and 87,89, and 90 octane has 10% ethanol in it. Ethanol is bad new for boats, small engines and destroys the carburators. It dries out rubber parts such as hoses, rubber gaskets, ect.. I heard China does not mix gas and ethanol. I replaces a vacuum hose a year ago. The hose became hard in one year- suspect is ethanol.. Ethanol dries out rubber and makes it hard and brittle. It also seperates and causes one to loose octane.

[lostforawhile]

mine only has 800 miles on it, and the vacuum controlled valve for that system is already leaking to atmosphere, causing a giant vacuum leak, get rid of everything but the crankcase breather which is needed , then you don't have cheap hoses and parts randomly failing 

[lostforawhile]

I finally took the rest of my pair canister off, it does nothing, vacuum or no vacuum, air goes right through it, you can stick a filter directly on the end of the hose going to the engine, the big hose, and it will function exactly the same. the canister with it's vacuum control, appears to be for appearance only, it does nothing useful except maybe filter the air. There is no logical reason for that hose to be shut off when the engine isn't running, even if it actually worked

[czmdiver]

Oct 8, 2017 13:35:55 GMT -6 lostforawhile said:

I finally took the rest of my pair canister off, it does nothing, vacuum or no vacuum, air goes right through it, you can stick a filter directly on the end of the hose going to the engine, the big hose, and it will function exactly the same. the canister with it's vacuum control, appears to be for appearance only, it does nothing useful except maybe filter the air. There is no logical reason for that hose to be shut off when the engine isn't running, even if it actually worked

Oh No it did something, it made someone feel good that they added a cost to your Scooter in a mindless attempt to keep air cleaner and as always in the end accomplished Nothing other than lightening your wallet.