Nice way to monitor air fuel ratio all the time

This nifty little tool shouldn't be a shock to anyone in the performance auto scene... I grabbed the gauge and sensor off my truck and i have been keeping an eye on the ratios... at first they were off the scale lean aka leaner than 17:1.. after bringing the low end adjustment screws out to 4.5 turns where they dont seem to do much more, it is idling and cruising low speed at a more acceptable 14-15 A/F.

I went up a few jet sizes and it seems that i went too far... over 1/3 throttle is pure 10a/f so ill see if i can make up a freer flowing exhaust, see if pods help, or get some smaller jets if all else fails.

This is a wonderful way to tune for pods or anything since you know immediately what your ratios are. These are getting cheaper, below the 300 mark, so it could be a good tool to have around, if you do a lot of tuning like me. (fuel injection, but getting places on my carbs)

Please excuse my messy garage haha

 

nice idea! does it only pull readings from that one exhaust though>?

 

Yes it does only read the one cylinder.. pod filters are on the way, so i went with an outside cylinder knowing they would be a little leaner with the more available and cooler fresh air.

Plans are to tune for the one cylinder and compare plugs.. i have a plug to fit in that port so its not too much of an eyesore when its off.. doesn't bother me though

By the way the header pipes are double wall... weird stuff

I would have liked to test the stock jetting / exhaust but thats not a possibility


This gauge / sensor ranges between 17:1 (super lean) and 10:1 (overly rich)

"perfect" mixture is right around 14.7, but you want a little extra fuel for cooling, especially for air cooled motors, so im planning to aim for 13-13.5 WOT.

At the moment WOT is around 10.5 and kind of bogs a little.. This makes me happy because i know ill get a lot of power out of leaning out the top end

It goes off the chart lean when you start running out of gas and have to switch over, so its nice seeing it, before you completely loose power and have to slow people down while you are waiting for the bowls to refill

 

Does it have to go in that spot of the exhaust, I have a 4 into 1 header and If I put it in the collector I could get the overall readings.

 

you could, i would have preferred that to not hinder the flow of exhaust on one cylinder. The downside, you wont see the change on one carburetor vs the set.. if you have 3 cylinders that are overly rich, and 1 that is really lean, it can look fine. I opted for the leanest cylinder and i hope the others are the same turns out. Realistically i can move that pipe around, but i don't want to risk snapping those damn exhaust studs.

 

I have seen those on e-bay for about 275.00. Just weld a bung in and start taking readings. I think it comes with software so you can go on a ride hit record and load the info into your PC. You can see really whats going on. Then the hard part is to try to tune the bad readings out.

 

I believe you are thinking of the innovative technologies wideband. Mine doesnt have logging capability, or any ability to plug into pc. Basically what you see is what you get haha

I have a close friend with that one in his car, its nice, but just shows numbers. The colored slider that goes around the gauge's face really helps when the numbers swing around a lot.. with his, its just a jumble of numbers.. kind of like why everyone hates electronic tachs!

 

When I was a kid, I did all this kind of stuff too. My '72 MBG had a host of Gauges it didn't need.

Oxygen sensors are an integral component part of FUEL INJECTION.
They adjust the Lambda Value (Fuel Injector Opening~Closing frequency) to maintain or adjust Fuel Supply.

At best it would be useful as a Diagnostic Tool.
Having that O~2 Sensor and Loop outboard like that is BEGGING for trouble.

 

On 2nd thought i shouldnt have put it on the kickstand side, but oh well.. It doesnt stick out as far as the picture makes it look. Plus im planning on having it plugged and running the sensor in my truck as normal, this is just meant for an aid so i know where the ratios are.

The stock sensors you are talking about are narrowband, and only accurate in a very small window around the ideal mixture. This is known as a wideband, and will tell you a wide range of mixture ranges 17-10 a/f.. this is what a dyno shop would use to tune your vehicle.. except for a less accurate in the tailpipe version... cant get much better than that.

 

I suppose that installing the sensor on the collector box would be more of a complete reading, but harder to diagnose a problem to one single carb.
The best way to do it is to have a bung welded to each header pipe to be able to take readings off each one by moving the sensor to each one. Take all four readings and adjust each carb, then remove the unit. Why not? You can just plug the bung with a bolt when your not using it.
So now you have me wondering if that idea is better or a colortune? Any thoughts?

 

This is what the little ports on the bottoms of the pipes are for; it's just that in 1980 nobody imagined it could be small enough to ever be "onboard."

 

Oh no! Another accessory I will need to get now.
I suppose a temporary mount will do and just use it to tune the carbs and remove it when I'm done.

 

this is what i used for the bung.. 4.99 for 2.... or hit up an exhaust supply place and get a couple.

I would believe its better than the colortune since you can use it on long trips and max rpm... but im not really familiar with colortunes

I was using it as a diagnostic tool for the pod filters. Ill take it off until i plan on doing some changes.

Its a wonderful thing when you can watch what your carburetors are doing in real time... after richening the low end screws I noticed my knee doesnt get uncomfortably hot on the side of the valve cover.. big difference.. poor motor! haha

 

Good to know. Thanks!

 

if i was going to make a setup like this for tuning purposes, tapped off the plugs on the bottom of the headers and use it with a volt meter and external battery for heat should i have a wide or narrow band sensor ?

 

If you are using an 02 sensor from a regular car then it could work, but not too accurately. It would be a narrowband, unless you got a wideband sensor for it.

Before i got the wideband, i was using the narrowband with a multimeter in my truck to tune.. It can give you an idea of where the mixture is, but its not accurate across a large scale like the wideband. If you are bored and have the parts sitting around, then by all means give it a shot... but keep in mind you need to know what voltage means what a/f... If you google narrowband oxygen sensor tuning you should find some info on what the voltages mean.

They sell gauges like mine that hook up to narrowband sensors for about 30 bucks. I wouldnt go that route again but like i said, if you have all the parts sitting around, slap a bung in there and give it a shot.

1 wire o2 sensors just arent heated. 3 wires are heated, widebands are 5 wire.

Look around on ebay and whatnot, there are a lot of these widebands on the market.. PLX, AEM, Innovative technologies.. This was worth it to me because i can tune both of my vehicles

My plan was to find someone in the area and borrow it but not many people had these.


With my stock airbox cut up and the K&N replacment filter, the low speed setttings are identical to the pods. High speed, the pods really lean things out in a good way.. I still need a little more leaning for power, but im a lot closer than i was before.. The bike will stay idling at 800 so im guessing its a good thing Definately feels better everywhere

In the near future i would like to block off the YICS port and see if it leans out WOT at all.. Which would indicate more airflow... Or lower vaccum signal.. either way i want to try this