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Hi all. A couple of questions about mixture. First, I meticulously set the floats to 15.5mm and they were parallel to the body of the carbs.

So when I did the emissions test, I was too high on Hydrocarbons. They told me at the testing place that means my mixture was too lean. I ran home tore the bike apart and reset the floats at about 15 mm. I didn't pass again, but I had turned the petcock off before the test and forgot to turn it on. I went through the test again with my choke partly engaged. I passed with flying colors.

Questions:

Is it possible that the bike was meant to run leaner than would be acceptable by the arizona emissions test?

Do you think I should adjust the floats again in the same direction?

When cruzing in high altitudes do you need a leaner or richer mixture? If J use the choke to control mixture (to a small degree) would it be convenient for going up into the mountains regularly?

Thanks,
Trent
 

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Damn emissions. Don't you just hate them. I have been fortunate enough not to go through all that BS especially on a MC.

I like the idea about keeping my carb running in tip top shape, but I blame Honda for making it so difficult due to the inherent design. The carb does not bother me on my GL1500 , it just getting to it.

I have never heard any emission requirements for MCs, so I just learned something. I would guess they would fall in some special class.

Yes, altitude will have an effect on F/A mixture. As you go up in altitude, they get richer. In a airplane, there is a control for this otherwise too much power is lost.
 

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You need a richer mixture for high altitude. Using the choke to obtain it is not an efficient way of doing that. Another turn out on the idle mixture screws might do the trick. The reason the HC is high with a lean mixture you get an incomplete combustion so there is unburned fuel in the exhaust.
 

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I don't quite understand how the examiner described your results.. I'll repeat a chart here..

Glad you passed, but you would have had to be extremely lean (and probably missing) to have high HC.... Since oyu had two things going (closed petcock and closed choke), it is hard to guess where you were..
 

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The form says these readings are in parts per million. The idle reading was about 2200. To pass you need less than 1800. The CO reading was 1.?? needs to be below 5.50 to pass.

With the choke on and petcock open I got an HC reading of 1648, and a CO reading of 3.81. I took the test once with the petcock closed (I think it was closed) and the last I took with the petcock open and the choke on (partly)

Lets see how that fits to your chart....
 

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I'm confused but thats easy to do! Rich to me means to much fuel and not enough air. Lean is to much air and not enough fuel. Rich would be unburnt fuel in the exaust chambers and lots of hydro-carbons. Lean would be higher CO readings from burnt exhaust gases. I would think that your bike would be exempt from emissions test because it's so old. I'm just glad we don't have that crap on motorcycles in Oklahoma.
Rumple
 

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It looks like the "precondition" standard (as opposed to the idle standard) is 500 ppm - 3 times fewer ppm. That one I failed really badly the first time at 2108 - had me rev the engine to 2200-2800 rpm. They didn't check that the last time. I think they were tired of me :D - gave me the certificate to register anyway.
 

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Maricopa county,in Arizona, is the only place in the WHOLE United States that tests motorcycles for emmisions. It was repealed in Pima county 2 years ago. There is a law repealing motorcycle testing in Maricopa county that has been signed into law, however,it does not go into effect until the EPA signs off on it.
 

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Boys, I hate to cut down your states: AZ appears to be trying to out due CA as far as being a leader or starting a new trend. Either that, or AZis way too slow for change.

AZ: Congratulation, you are one of two counties left in the US that still requires emissions testing for motorcycles. Maybe its only one now. I hope they are both not in AZ ( I hate internet sources).

http://www.mma-az.org/Legislators.html

These emission laws were always and stillare crazy and a waste of everyone's money. It's pretty funny so long as it is in your back yard. It become serious if it were in my back yard. Funny in yours, serious in mine.:goofygrin:

I was is Albuquerque for four years. Work location required vehicle emissions, but my residence did not. No exemption like"Area A". Amazing, at times I think states do more stupid $hit than the federal government. Ooo.:shock: :gunhead:
 

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I do like the sheriff of Maricopa county though! Hope he's still there.
 

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I am glad we do not have to put up with emission standards around here. But I suppose if it does come to pass, one would have to carefully adjust the air/fuel mix. I have such a device it is called a color tune, it has a special spark plug so you can see the color of the spark. I used to use it for the Harley and Yamaha bikes to perfectly tune the Carbs. Have no use for it with fuel injection and computerized ECU units.
But does work well.

Kit
 

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...But I suppose if it does come to pass, one would have to carefully adjust the air/fuel mix....
A carb needs to be able to provide proper mixtures at all engine rpms. The only adjustments on acarbs is at idle. Off idle, there is no adjustment.

Emission testing is done at low and high rpms. The only adjustment for higher rpms is changing jets or float levels. Disconnecting vacuum hoses would not be an adjustment.
 

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Foosman(5) wrote:
...But I suppose if it does come to pass, one would have to carefully adjust the air/fuel mix....
A carb needs to be able to provide proper mixtures at all engine rpms. The only adjustments on acarbs is at idle. Off idle, there is no adjustment.

Emission testing is done at low and high rpms. The only adjustment for higher rpms is changing jets or float levels. Disconnecting vacuum hoses would not be an adjustment.
Agreed, older bikes might have a time passing that test if they do it properly and do test at 3000 rpm or so. New bikes have Cats and other things to control pollution, older ones do not. A hardly with open full flow pipes and enriched fuel would never pass that test. Surely they have some exceptions for older bikes.......maybe not, it is after all the government.

Kit
 

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You need a richer mixture for high altitude. Using the choke to obtain it is not an efficient way of doing that.
Other way around. High altitude less air - Carb venturi nozzle create a pressure differentialwhich results in less air same fuel. Rich requires re-jetting or smaller jets.

In a small airplane, they do not have chokes. The old definition for a choke was an obstruction to the air way. FAA would never allow this - no air filter and no choke. Chokes are different in Hondas. Small airplanes have a fuel enrichement valve that is controlled by the pilot, and basically it is a manually controlled main jet. He could use it to assist starting, but it is there for altitude. The pilot leans the mixture as he goes up inatitude and vise versa.

Polution control: All that crap does is serve to confuse and fail emissions.Even if you have no emission testing, it is a pain towork on andis probably 90 percent neglected. EGR, Smog pumps, air injections reed valves, and AIR all make diagnostics that much harder. Simple diagnostic trys to eliminate these function as if they were not there. That gets you to a simple baseline, but then the "controls" screw everything back up.
 

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I appreciate the sympathy. I am a student so I will likely get a real job in the near future and move away from all these regulations.

I need to know if I am running too lean for the good of my engine. Any thoughts on this? If it helps I left the HC readings above in another post in this thread.

Running too lean would also cause a loss of power wouldn't it? When starting off in first gear, the engine shutters like it wants to die. My guess is it is starving. Could I be right?
 

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Damn emmision, aren't you the lucky one.
Running too lean would also cause a loss of power wouldn't it? When starting off in first gear, the engine shutters like it wants to die. My guess is it is starving. Could I be right?
Correct, but your have two fuel delivery systems.

Typically, a leaner mixture does not delivery max power for a given amount of fuel. The F/A stochiometry mixture is say around 15:1.For performance, a richer ratio is preferred, and for fuel economy a leaner mixture.

A typical carb F/A ratio chart would look like a bath tube curve. Richer at idle, leaner in the mid-range power for cruising, and richer at high power.

At idle, the mixture screw is typically set to deliver thehighest rpms for a given vacuum. After set, half turn richer is the final setting. This idle circuit is typically only good for approximately ~1,500 rpms. Then, the air flow transitions to the main jets for fuel delivery which is dependant upon float height. An accelerator pump aids the F/A ratio from going lean during this transition or rush of air through the throat. I like mine to run rich to prevent that bog/hesitation.

I can not say I am an expert with emissions. Your initial HC readings were high, but they told you it was lean.I would have thought the opposite, and my thinking would have been too rich initially, and choking would make it worse.

From your second post and the chart, looks like you passed, right? When I passed, I figured I was good for another year or two.
I need to know if I am running too lean for the good of my engine.
As far as running an engine lean, the only real problem would be for high performance engines. Excess oxygen and elevated temperatures would oxidize the aluminum and blow holes in the piston. You will not have this problem. Like I said, I set mine a little rich.
 

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From your second post and the chart, looks like you passed, right? When I passed, I figured I was good for another year or two.
Yes I did pass. Just worried about (1) damaging the engine and (2) running below peak performance, or at least very far from peak. This is my first wing so I am not sure how it would feel running perfectly.

That is a lot of really useful information Foosman. THANKS!
 

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Check your plugs after a run..if any of them is white or light gray you running lean on that carb ..if tan just right and if black or sooty too rich..

Stuttering on take off is more likely not enough throttle from you.
 

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If you run too lean for too long there is a risk of burning an exhaust valve. I bought a bike last summer that had no compression on one cylinder. After taking the head off I found one exhaust valve that had a large hole in it. The other two had the faces eroded so bad you could cut yourself on the edges they were so sharp. I replaced all 3 and found a large air leak that was causing the lean condition. Runs like a new one now still after 11.000 miles.....
 
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