My NEW XF200 qingqi (Pics!)

**MJH** · 10-02-2010, 05:06 PM

I’m not a physicist, the combustion has peak temperatures and they occur at some point? Mixing air and fuel has some peak point in derived combustion temperatures. This device prevents that from occurring, it is timed or configured to open when that occurs typically. Adding the exhaust gas will do that, but seeing that Nitrous oxide production occurs at 2500 degrees really confuses me, that must be an internal flash temperature potential? Seems very high to me. Adding exhaust to the air keeps that from occurring that peak flash temperature in the combustion chamber.

The EGR opens and closes, its not always open but must be opening in a range that has the highest potential for that highest peak combustion temperature. So you never get to that peak with it operating correctly.

Now it is gone and you have an over all lower temperature on the head? But inside the engine you now have these flash points that are higher.

Man you have a lower average temp but you now have these peaks. The fuel to air mix and firing timing? The same as before in some of the range but in other parts of the throttle range you now do not have the EGR effect. Your getting these flash points that are hotter and that could be affecting the plug.

How does the time of firing work on these bikes, is it electronic? Its not fuel injected its mechanical so in some instances the fuel to air mix and firing is not correct. That would be the range that the EGR was in effect. I am not taking mine off because I cannot ignore that that bikes configuration is set for it to be there. A bike that did not have one from the factory would help, how is set up? Is the timing preset in the CDI or can it be adjusted? The carburetor may need adjusting to or in the range that the EGR operates, when is it open and when is it closed? Which jet is in effect in that range.

A white plug is a sign of the fuel to air mix being off or the ignition timing. Maybe I am wrong but it is currently configured for the EGR being there.

Everything has a range, it has high points and low points setting are configured to accommodate the range.

Put the EGR back on and then put in a new plug, then check the plug. Process of elimination if that has an effect on the plug then what is different and why.

I think the EGR opens in the midrange…..it not open at idle and closes at upper range to full throttle I believe. Other removed that device but they also added performance exhaust and increase the jet sizes? They may have set it better to operate without that device by doing that?

The half color is a sign of an uneven ignition and all related to fuel to air and timing. The EGR is integral in that….

**thedirtypickle** · 10-02-2010, 05:24 PM

You sound very knowlegable MJH, and I wasn't trying to down you man. Your probly right.

UPDATE:
I just installed a larger main jet of 127.5 and wowsers. This bike is the bees-knees after that. The two sided plug color has mostly gone away and is showing very nice color now (greyish/light-brown). I've seen other threads that are talking about the needed up-jet from stock and boy-o-boy were they right. If I were to say so, it had to have givin and extra 2-3hp gain. It's quite substantial, and I highly recommend the 127.5 jet.

One more thing, I'm retracting taking that canister by the battery off. Reason being that when you are putting along and you dont have a full tank of gas there seems to be negetive pressure in the gas tank causing you to sputter to a stop. Fixed of coarse by opening the gas cap and continuing on your way. I suppose you could leave the hose going to the tank open, but you may get some spillage from time to time. No Biggie, but keep it in mind.

I'm currently hunting for pooper pipes and found a few on ebay, but sadly winter is comming and I dont have much more time to ride here in minnesota. :(

**thedirtypickle** · 10-02-2010, 05:30 PM

You know MJH, come to think of it, I was blowing in the little unit and if I remember right, I thought it was only able to suck air in to the engine and not push exhaust into the air box. I've thrown mine away, so I cant check. It is, in fact, how scooter's systems work. They had the same kind of unit that ONLY injected air into the exhaust stream in the attempt to have "cleaner" emmisions.

**MJH** · 10-02-2010, 05:42 PM

Originally Posted by thedirtypickle

You sound very knowlegable MJH, and I wasn't trying to down you man. Your probly right.

UPDATE:
I just installed a larger main jet of 127.5 and wowsers. This bike is the bees-knees after that. The two sided plug color has mostly gone away and is showing very nice color now (greyish/light-brown). I've seen other threads that are talking about the needed up-jet from stock and boy-o-boy were they right. If I were to say so, it had to have givin and extra 2-3hp gain. It's quite substantial, and I highly recommend the 127.5 jet.

One more thing, I'm retracting taking that canister by the battery off. Reason being that when you are putting along and you dont have a full tank of gas there seems to be negetive pressure in the gas tank causing you to sputter to a stop. Fixed of coarse by opening the gas cap and continuing on your way. I suppose you could leave the hose going to the tank open, but you may get some spillage from time to time. No Biggie, but keep it in mind.

I'm currently hunting for pooper pipes and found a few on ebay, but sadly winter is comming and I dont have much more time to ride here in minnesota. :(

well there you go...I think that the 127.5 had no advantage over the 125 it offered no additional hp? But the DYNO test included a performance pipe and resulted in 19.4hp?

It was with a main jet from 122.5 to 125 and the slow jet from 32.5 to 35.

I will be looking at exhausts this fall....a local manufacturer HMF I want it to look stock. Flat black with a polished tip, I also want it to have the same mounting points. I want a very good muffler...that is made of good material. Here is their website: http://hmfracing.com/

**MJH** · 10-02-2010, 05:50 PM

Originally Posted by thedirtypickle

You know MJH, come to think of it, I was blowing in the little unit and if I remember right, I thought it was only able to suck air in to the engine and not push exhaust into the air box. I've thrown mine away, so I cant check. It is, in fact, how scooter's systems work. They had the same kind of unit that ONLY injected air into the exhaust stream in the attempt to have "cleaner" emmisions.

EGR devices are on cars also they are a reed valve they open with vacuum off the carburetor.
http://www.asashop.org/autoinc/nov97/gas.htm

**thedirtypickle** · 10-03-2010, 05:02 PM

I will say that those HMF pipes are pretty.

I agree with you what an EGR system is, and all i'm saying is that it drew air into the engine from the airbox. I have three chinese 50cc scooters and they have the same type of setup to where they...

You know what? this thread is getting nowhere... Your right... EGR blah blah blah

::Thread closed::

**MJH** · 10-04-2010, 02:35 AM

I agree it got boring...but at least people now can understand what the heck it actually is and what the heck it actually does. Maybe? LOL

**jape** · 10-04-2010, 03:13 AM

Actually it was interesting and slightly amusing too, thanks! Most here just watch and don't reply unless directly interested.

**thedirtypickle** · 10-08-2010, 02:07 PM

Not to beat a dead horse, but I found out that the little box that we were calling an EGR is only an air injection system. All it does is inject extra air into the exhaust to create the appearance of lower emissions (less carbons per unit). It's not an EGR people, they call it something along the lines of "secondary air intake".