exhaust gas analyzer??

[cals400ex]

has anyone tried one of these?? i am not quite sure how they work or what they cost. any info would be great. thanks cal

[BIGRED400]

It read's fuel to air mixture for optimal tuning.here is a few of many for sale....takes the guesswork out of the old days with vacuum gauges
http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=112585&prmenbr=361
http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=1595&prmenbr=361
http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=1526&prmenbr=361

[Aceman]

The only way an analyzer would work well for you is if you drilled a hole in your exhaust pipe, welded a nut on and screwed the sensor in. Otherwise all you could do is hold the sniffer next to the exhaust pipe with your quad stationary and not under a load. So the only way to get a true reading is running your engine at different rpms under a load, etc. You can do that either by mounting one permanently to your exhaust pipe and reading the gauge while you ride your quad or possibly sticking your quad on a dyno and analyzing the exhaust. But the latter would be pointless because you can jet it by the hp numbers you read off the dyno sheet and not the exhaust analyzer. What I think you should do is not worry about an analyzer because you know how to jet carbs properly and the money spent on an analyzer isn't worth the gains, if any you would experience.

[JD400exrider]

The shop by me has a dyno with a sniffer. You can get the HP numbers but more important you can also get tou hetting dialed in through the sniffer. Aceman are you saying the sniffer on the dyno is not going to acurate.

[BIGRED400]

From the people I've talked to it put's the mixture at right on but each motor will be different, a 14/1 may work for a certain engine combination and 12.5/1 may be right for another...I hope this helps:)

[norcalatver]

The problem with jetting by h.p. numbers on the dyno alone is you could jet too lean and burn your motor up! The sniffer on the dyno goes up inside your exhaust, (you have to have an open end cap, no spark arrester) and it tests exhaust gases at different loads from o-however many rpm's your engine is designed for. I would never jet by dyno numbers alone! If you do then you also need to do a plug check after you've jetted to make sure you're not too lean.

[2004TRX450R]

Originally posted by norcalatver
The problem with jetting by h.p. numbers on the dyno alone is you could jet too lean and burn your motor up! The sniffer on the dyno goes up inside your exhaust, (you have to have an open end cap, no spark arrester) and it tests exhaust gases at different loads from o-however many rpm's your engine is designed for. I would never jet by dyno numbers alone! If you do then you also need to do a plug check after you've jetted to make sure you're not too lean.

This is not true. I have dyno tuned a few bikes. Even if they are lean it isn't going to be run long enough to burn it up and if it is that lean it will be pinging and if you have any idea what you are doing you would hear it and stop. The only exception might be an old clapper that is ready to go already anyway and if you forget to turn the fan on and it overheats and siezes. If you run it and get a air/fuel curve on it there is no need to check the plug as you can already see how it is running and weather it is rich or lean. Some bikes do like to be richer or leaner than others to make more power. If you get one that likes it a bit leaner then the only real problem you might run into is that once you go somewhere else if it is lower alititude or colder so that it makes it run leaner yet you may end up with lean problems and have some issues with it that way. But if you are tuneing to this exetent you really need to know how to tune it once you get to your rideing area too. It will change depending on where and when you are rideing.

[BIGRED400]

The problem with jetting by h.p. numbers on the dyno alone is you could jet too lean and burn your motor up! The sniffer on the dyno goes up inside your exhaust, (you have to have an open end cap, no spark arrester) and it tests exhaust gases at different loads from o-however many rpm's your engine is designed for. I would never jet by dyno numbers alone! If you do then you also need to do a plug check after you've jetted to make sure you're not too lean.

What make most HP most of the time is short lived....leaner makes most HP.....but for only for a short time....we need a happy medium...........in the long run for the least my wallet spent........what good if you can outrun someone today BUT not tommorrow??
:rolleyes:

[norcalatver]

Originally posted by 2004TRX450R
This is not true. I have dyno tuned a few bikes. Even if they are lean it isn't going to be run long enough to burn it up and if it is that lean it will be pinging and if you have any idea what you are doing you would hear it and stop. The only exception might be an old clapper that is ready to go already anyway and if you forget to turn the fan on and it overheats and siezes. If you run it and get a air/fuel curve on it there is no need to check the plug as you can already see how it is running and weather it is rich or lean. Some bikes do like to be richer or leaner than others to make more power. If you get one that likes it a bit leaner then the only real problem you might run into is that once you go somewhere else if it is lower alititude or colder so that it makes it run leaner yet you may end up with lean problems and have some issues with it that way. But if you are tuneing to this exetent you really need to know how to tune it once you get to your rideing area too. It will change depending on where and when you are rideing.
2004trx450r, you go ahead and run your motors lean, I prefer to run them spot on. A lean mixture WILL overheat your engine and cause premature engine failure. Just ask any engine builder!

[cals400ex]

well, has anyone dynoed their 400ex? if so, what jets did you end up with and what are the mods on the bike?? mention what carb too. thanks cal

[norcalatver]

Originally posted by cals400ex
well, has anyone dynoed their 400ex? if so, what jets did you end up with and what are the mods on the bike?? mention what carb too. thanks cal
When I went into the dyno I started with a 172 main jet. After the dyno session I ended up with a 162 main using ultimate 4 gasoline. Ultimate 4 causes a slightly leaner condition than conventional race fuels. If I were to use typical race fuel I would drop to a 160 main jet. B.T.W. , I'm running a 493 stroker with 12.88:1 compression, full race cam, large valves, 39mm FCR carb, etc. everything you can do is done. The dyno was well worth the 40 bucks!

[2004TRX450R]

Originally posted by norcalatver
2004trx450r, you go ahead and run your motors lean, I prefer to run them spot on. A lean mixture WILL overheat your engine and cause premature engine failure. Just ask any engine builder!

I never said I ran them lean. If you know what you are doing you can dyno tune a bike properly I was just saying that if it is lean you aren't going to burn it up in one dyno run especially on a 4 stroke and you will be able to see if it is rich or lean and adjust accordingly. I do it with an EGA so I know exactly where the jetting is. It's supposed to be in the mid 14:1 range but most bikes like it more in the high 12:1 to low 13:1 range If you plan on doing a lot of very long high speed runs at full throttle such as in desert raceing NOT drag raceing or sand dune rideing but I mean full throttle for minutes at a time you usually want to go one size richer on the main. This will help keep it cooler and last through the race.

[BIGRED400]

Originally posted by 2004TRX450R
I never said I ran them lean. If you know what you are doing you can dyno tune a bike properly I was just saying that if it is lean you aren't going to burn it up in one dyno run especially on a 4 stroke and you will be able to see if it is rich or lean and adjust accordingly. I do it with an EGA so I know exactly where the jetting is. It's supposed to be in the mid 14:1 range but most bikes like it more in the high 12:1 to low 13:1 range If you plan on doing a lot of very long high speed runs at full throttle such as in desert raceing NOT drag raceing or sand dune rideing but I mean full throttle for minutes at a time you usually want to go one size richer on the main. This will help keep it cooler and last through the race.


Optimal is around 14/1 most of the time 12-13 for most Hi-performance/trail riding(reliable) from what I've read.
http://www.docv.org/articles/bench4.htm

[cals400ex]

Originally posted by norcalatver
When I went into the dyno I started with a 172 main jet. After the dyno session I ended up with a 162 main using ultimate 4 gasoline. Ultimate 4 causes a slightly leaner condition than conventional race fuels. If I were to use typical race fuel I would drop to a 160 main jet. B.T.W. , I'm running a 493 stroker with 12.88:1 compression, full race cam, large valves, 39mm FCR carb, etc. everything you can do is done. The dyno was well worth the 40 bucks!


what are the other jets your using? what needle and clip position, fuel skrew location, pilot jet, air skrew location, and main air jet?? thanks for the help.

[norcalatver]

Originally posted by cals400ex
what are the other jets your using? what needle and clip position, fuel skrew location, pilot jet, air skrew location, and main air jet?? thanks for the help.
I'm not positive, LRD set it up for me when I originally purchased their engine kit. I called them and they couldn't tell me what they had done. The only time I've ever touched it is when I recently had the 493 done and all I did was change the main jet. Ironically, after dynoing it, the main jet went back to almost where LRD originally had it at 160.

[boogiechile]

Stoicheometric ratio is 14.7/1 but the most power is usually at 12.5/1. so there is really no danger of dynoing for power and being lean. Most of the analyzers shown in this thread are not really analyzers but exhaust gas oxygen sensors hooked to a voltage meter that shows rich or lean based on the volts it sees from the sensor. Most of these can not tell you the actual ratio and they require mounting a sensor in the pipe near the head. A real exhaust gas analyzer that measures 4 or 5 exhaust gases plus gives you the actual fuel ratio can be found at good auto repair shops. You have to be able to get the probe all the way up in the pipe so no spark arrestor could be on. A good portable unit costs around 4,000 bucks. a lot of car shops will test the exhaust for you, you can get an actual ratio reading at all throttle positions and use this info to set the needle and jetting. Believe me this is the best way to set up your carb. I work at a technical college where we have them in the auto program and I use one to set up my jetting, works great, no guessing or seat of the pants stuff.

[cals400ex]

yeah, well i know i won't be drilling a hole in my exhaust. i figured this probably won't be best for me.

[boogiechile]

you don't have to drill a hole to use the exhaust gas analyzer like you do with those rich lean monitors. you just stick the probe in the end of the pipe.

[hemp450r]

IF YOU WELD A BUNG INTO YOUR HEADER PIPE BEHIND THE HEAT SHIELD, YOU CAN SIMPLY REMOVE THE SENSOR WHEN YOU ARE DONE JETTING AND INSTAL A PLUG. YOU DON'T EVEN SEE THE WELD. PERFORMANCE IS NOT SACRIFICED, BUT YOUR JETTING WILL BE SPOT ON, WHEN THE TEMPERATURE CHANGES OUTSIDE YOU CAN PUT YOUR SENSOR AND GAUGE BACK ON SET JETTING AGAIN AND REMOVE. THIS CAN ALL BE DONE AT HOME, AND YOU DON'T HAVE TO TRUST THAT IT HAS BEEN DONE PROPERLY! I RECOMMEND IT FOR PEOPLE THAT ENJOY WORKING ON THEIR OWN EQUIPMENT .

[cals400ex]

this is one old thread.............

[JOEX]

Originally posted by cals400ex
this is one old thread.............
Noticed that when I saw you asking about jetting:p

[cals400ex]

yeah, i jetted that 400ex more times than i want to think about...