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Discussion Starter · #1 ·
So I picked up a Koso Air Fuel Ratio Meter and followed the installation for welding the bung into the pipe. It is a wide band meter and looks like it will work pretty well.

My question is how do I test the air fuel ratio? Can I do is by just having it sit on the driveway? Does it have to be with a load (riding)? On the gas really hard? The instructions don't really explain how to use it ... more how to install it.

Anyone with experience that can give me some tips would be appreciated.
 

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I am unique
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Drive it like you stole it..............lol..........allow the bike to idle and get to temperature and drive it, check the A/F ratio at all throttle positons under all loaded conditions, allow to idle to get the ratio there also and adjust accordingly, simple.........
 

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how hard was this to install?where did you buy it from?Mounting locations?thanks
 

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Discussion Starter · #4 ·
I got it through work. You can get them through dennis kirk though. It was pretty easy to install. Once you weld the bung into the exhaust there are only two wires to hook up: a power and a ground.

Took it for spin around my apartment driveway and it idles at 13.8 (rich). So if I get on the gas it goes to 15.2 (lean) once I stab the gas.

If its lean for a second is that ok? How long can it be lean for before I need to worry. I know it will be lean for a second before the accelerator pump kicks in. Should I more worry about once it levels out and cruising?
 

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Discussion Starter · #6 ·
Ok. I'll back my idle screws out a little. It was down in the 12 range but I turned them in because thought I was supposed to shoot for the 14.7 range.
 

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What brand and model number is your gauge and did you mount it or is it only hooked up for testing...Pictures?
 

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I use a NGK AFX wide band O2 meter. I have been told by a couple builders to shoot for 13.1-13.2 :1 for under load at WOT.
 

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Also dont forget if your running FCR's that you have to hold the throttle at a certian spot for 3 seconds or more. Other wise your getting a false reading on your meter because of the accelerator pump. If you just doing quick stabs on the throttle the accelerator pump is also squirting fuel. Wich will not allow you to see if your main jet is lean or rich.
 

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If you have stock carbs and you stab the throttle and it goes lean then richens back up it is because there is no accel pump on those carbs. If it does it on FCR's you need to adjust your pump.

13.8:1 at idle isn't bad. 14.7:1 at idle will work but will run hot at an idle. I usually like to make it richer at idle that way when you stab the throttle or load the engine it is closer to its max hp afr and generally has better throttle response. the 14.7:1 stoich afr is a compromise between best mileage and emission output for cars, thus why cars idle and cruise at this ratio.

Also you need to ride and jet it that way. reving the engine and holding throttle position at different rpms while in neutral will be no where near accurate.

Oh and atv's like to run leaner than car engines. Cars produce max hp down into the 12's ~12.8 but typically a raptor is around 13.1:1. If you can get it setup to run between 13:1 and 13.5:1 at all times you will be golden.
 

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Discussion Starter · #13 ·
The one I bought is this one:
Dennis Kirk Part #: 173323
Manufacturer Part #: BA004064

It comes with a pivot mount that has two holes in it. Because it comes with a backer with matching holes and two pieces of rubber I figure they expect you to drill and mount it to a fender or anywhere else. I just enlarged one of the holes and mounted by means of the handle bar clamp bolt. This is going to work for temporary tuning and once I'm good then its going to come back off.
 

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Discussion Starter · #14 · (Edited)
Here are the pictures of it mounted (with my trailtech vapor) and where I put the sensor on the exhaust.

Terry,
I think it may also go from rich to lean but only for a second due to a lag in the accelerator pump. I'm assuming that is normal and perfectly fine for a second right? After that it should go to rich (due to the accelerator pump boost) and then level back out at a steady state right.
 

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You might want to look in to a heat sink for your o2 meter. It is possible to overheat them. I dont know the exact temp that problems start to occure. I have just herd of it happining.
 

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Discussion Starter · #16 ·
Ok. The instructions said that to mount the O2 sensor 200 mm from the flange (picture showed a flat flange on the end). Of course the raptor has the loose-slip-over flange but I decided to go from the flange instead of the end of the pipe. I actually went a little further than the instructions said anyway 8in instead of ~7.75in)

How would you say to do a heat sink? Piece of aluminum with a hole in it?
 

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you just put the sensor in the worst possible position.
the sensor may deff. NOT be hanging upside down.
right now moisture is dripping into the sensor wich is causing it to fail in short time.
replace the sensor to between 10am and 2pm.
i would replace the sensor just after the bend, next to the cil.
 

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this will help.

 

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Discussion Starter · #19 ·
$#!+... Wish the instructions would have told me that. I'm only going to have it on for a day or two and then the sensor is going to get removed (it comes with a plug to thread into the hole. I put the bung in that position so that when the sensor gets removed it will not be as visible.

Also how is moisture "dripping into the sensor"? I shut my gas off and run my quad until is starts to stutter (lean) and make sure I don't get water in my tailpipes when washing it. Also, I plan on tuning tomorrow (its dry out) and then removing the setup.
 

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Ok. The instructions said that to mount the O2 sensor 200 mm from the flange (picture showed a flat flange on the end). Of course the raptor has the loose-slip-over flange but I decided to go from the flange instead of the end of the pipe. I actually went a little further than the instructions said anyway 8in instead of ~7.75in)

How would you say to do a heat sink? Piece of aluminum with a hole in it?
It is just an adaptor that threads in to the O2 bung. Then the sensor threads in to the heat sink. It just gets the tip of the sensor out of the exhaust.

http://cgi.ebay.com/ebaymotors/OBX-...faeQQitemZ390303432622QQptZRaceQ5fCarQ5fParts

 
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