A/F Ratio...Dialing In

[Diablotin]

Yea same here - about 2.5 turns out of all 4, then ride some. Next time the spark plugs are out, if they look a bit white the A/F screws are going 0.5 turn out, if black they go 0.5 turn in.

Ended up doing that too, I would say i'm accurate with 1/4 turn of possible error

 

[DaMax]

Thanks guys for the great input!!

I am going to set them all at 2 1/2 out and go from there. :eusa_dance:

Cheers

 

[Sonoran6]

2 questions:
Is the a/f screw adjusting +,- fuel or air?
Should they all be the same? After removing the factory brass plugs, I checked them. 1 is at 3 turns out. 2 at 2.5 and 1 at 2.25.

 

[Rusty McNeil]

They're carbs. If you know it's firing on all cylinders and the plugs look right;

Then,

An A/F monitor in one of your exhaust pipes that's looking at only two cylinders is perfectly adequate.

After that you gotta kind of take it on faith that if all cylinders are firing, the valves are adjusted perfectly, your compression and leak down tests are equal and all four carbs are set up the same then you're good on all four cylinders for A/F ratio.

Kajllion dollar turbo street cars most often are only looking at half a bank of a V6 or V8.

If your really anal you can install bungs in both pipes and move it back and forth. Gets you all four two at a time.

Or go with a 4-1 exhaust and monitor all four of them.

Or two bungs on a 4-2 and a two channel two sensor setup.

Or install four bungs, one in each pipe, and move it around to check each cylinder individually.

Or spend really big bucks for a four channel, four sensor setup and go then all. And I do mean REALLY big bucks.

I don't Know about all WideBand a/f set ups but if its idle a/f ratio your after the ones I've seen aren't terribly meaningful at simple idle rpm and need more rpm's to get a good read.

 

[Rusty McNeil]

The exhaust bungs are easy, just drill and tig or mig weld. I even had one installed in the factory collector box/garbage can thingie when I had the stock exhaust.

 

[DMAN999]

2 questions:
Is the a/f screw adjusting +,- fuel or air?
Should they all be the same? After removing the factory brass plugs, I checked them. 1 is at 3 turns out. 2 at 2.5 and 1 at 2.25.

1. +/- Fuel ( I believe)
2. They are set at the Factory at the supposed Optimal Setting for each individual Carb.
Mine are similarly set: 1 @ 3, 2 @ 2.5, 1 @ 2.75, these seem to be the best settings with My Open Cap SuperTrapps.
Originally mine were all about 1/4 turn in from where they are now.

 

[Sonoran6]

1. +/- Fuel ( I believe)
2. They are set at the Factory at the supposed Optimal Setting for each individual Carb.
Mine are similarly set: 1 @ 3, 2 @ 2.5, 1 @ 2.75, these seem to be the best settings with My Open Cap SuperTrapps.
Originally mine were all about 1/4 turn in from where they are now.

So, turning them in would lessen the amount of fuel? I am going to pull the plugs in a few, if theyre black or smell like a lot of gas i need to turn them in a little? because theyre getting too much gas? I ask because at stoplights, my exhaust smells like a lot of gas, and my friend said he could smell tons of gas when i blew by him on the freeway.

 

[mr.maxx]

So, turning them in would lessen the amount of fuel? I am going to pull the plugs in a few, if theyre black or smell like a lot of gas i need to turn them in a little? because theyre getting too much gas? I ask because at stoplights, my exhaust smells like a lot of gas, and my friend said he could smell tons of gas when i blew by him on the freeway.

yes turning them IN will lean the mixture.....

 

[DMAN999]

If the Plugs are Tan/Beige I would leave them alone and live with a slight Fuel smell.
But if they are Black, I would try them 1 at a time and see how it does.
Maybe start with the one that's at 3 (if the plug is Black) and turn it in to 2.75 and see if that helps, if not try 2.5.
I would NOT recommend setting any of them at less than 2.25 though just to be safe.
Too lean can be MUCH more harmful than too rich.

My Plugs are all consistantly an almost Perfect tan, but I also have a slightly rich (fuel) smell at idle, I just ignore it because the Bike runs like a Raped Ape.

 

[Rusty McNeil]

Air from PAJ 1 and PAJ 2 combines with fuel from the pilot fuel jet ( the tiny one in the jet block) and is then fine tuned (flow) with the idle screw A/F adjustment.
This air fuel mixture predetermined by paj1, oaj2 and the pilot fuel jet is added to the airstream slipping past the barely open throttle plate.

It's easier to understand if you Ignore the air in that predetermined mixture and just consider it fuel that your controlling the flow rate of as it enters the air stream

Individual differences in valve adjustments, synch, compression, ring seal maybe, cylinder temp, etc cause them to be different if they are set perfectly for each cylinder.

I usually don't get to hung up on it, if the plugs looks good, it's firing on all cylinders at idle, and it doesn't spit back thru the carbs when cold (lean idle mix)
And it passes the blip throttle test then I'm happy.
Blip throttle test is at idle, slight blip and takes a bit to return to set point then it's lean, blip and it goes up, then down below set point and either recovers or dies its rich.
If its too lean it'll occasionally spit thru the carbs when cracked open from idle, and do it less or mot at all when warmed up completely.

If it starts without the choke then its way too rich to begin with.

I too have never gotten all cylinders too respond equally when simply closing them till it stumbles. I can get close that way tho'

 

[Sonoran6]

all my plugs are white.. did a plug chop, WOT in 3rd and hit ignition switch and let off the throttle. rolled into my garage. they all look like this.

 

[DMAN999]

Looks like you could actually open those A/F Screws up a bit.
Your A/F screws are set pretty close to mine but I have Open End Cap Supertrapps on mine which are a bit richer than the Stock Exhaust.
Which makes sense becuase the factory always did tend to set those on teh Lean Side for emisions reasons.

 

[Sonoran6]

i have my stock exhaust drilled out 5/8" and a K&N filter. i read that if you need to go more than 3 turns, re-jet. true?

edit

just re-checked em and noted the factory settings in my records this time.
1-2.5
2-2.75
3-1.75
4-2.75

 

[DMAN999]

i have my stock exhaust drilled out 5/8" and a K&N filter. i read that if you need to go more than 3 turns, re-jet. true?

You'd have to ask Sean Morley to see what he recommends but I know plenty of people go out to 3.5 without any problems.
If I remember correctly I set mine at about 2.75 -> 3.25 when I had the Drilled Stock Exhuast and K&N Filter.
And I know a few guys have set them as far out as 4 Turns with no issues.
I would turn then all out 1/4 turn and see what that does for you.
You really should Not have to re-jet with Stock Exhaust (even drilled).
PS
Here's a pretty good Spark Plug Chart:
http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

 

[Sonoran6]

2.75-3.25 is 1/2 a turn, if I do only 1/4 turn what exactly am I looking for? A difference in plug color?

 

[[email protected]]

all my plugs are white.. did a plug chop, WOT in 3rd and hit ignition switch and let off the throttle. rolled into my garage. they all look like this.

Doesn't look too white to me. How is it running?

 

[sdt354]

all my plugs are white.. did a plug chop, WOT in 3rd and hit ignition switch and let off the throttle. rolled into my garage. they all look like this.

I'd take that all day. Nothing wrong with those plugs. Don't drive youself crazy trying to get a perfect tune. Unlike injection, carbs.
won't compensate for changes in temp. elevation ect. The idle A/F does somewhat effect other circuits, but when riding? Unless way out of the ball park
with idle, tuning the midrange, and top end is more worthwwhile. The correct main jet is the starting point.
Steve

 

[tugla]

doing a wide open cut would more tell you about main jet not a/f screw.....plug looks good to me

 

[tugla]

try running reg ngk stock plugs,they work awesome vs other styles

 

[dannymax]

try running reg ngk stock plugs,they work awesome vs other styles

:surprise::surprise::surprise: Rov saying "Go stock or GO Home???"

Hahaha, what's this world coming to? :rofl_200::rofl_200::rofl_200: