engine sucking air somewhere

[Bhawkins854]

I've been battling this issue after I completed a bunch of new mods to my 08' 117. The first issue I noticed is the fact I can back my a/f screw all the way out before the engine wants to stumble. Also I get a backfire at the air cleaner when I rip the throttle at idle. This all points to a lean condition or intake leak I've been told. I'm running a .032 intermediate. I've checked numerous times by spraying brake cleaner on both intake manifold flanges. My plugs have soot around the base so that tells my I'm not lean on my int. Side if I am correct. A knowledgeable bike mechanic told me I'm sucking air somewhere but where could the problem be, as I just changed both intake o-rings and carb o-rings? The a/f mixture screw problem seems to be a huge red flag? Any suggestions?

 

[Sven]

Look up manometer. Buy a cheap one. Make sure that step-down dowel is in every tube. You'll suck the crap into the engine if you don't.

Think of the low speed screw as a jet. Nature is going to want a different air adjust, you mod some intake/exhaust area. You already checked for air leaks. Next move. Where is the air screw? Enter manometer.

Find the highest peak. This says. I'm sucking in lean mean. I don't need more, I don't need less. The manometer is going to peak and drop or drop. Find peak so it goes nowhere but there. If you have an ear for the idle drop, go for it.

YOu'll wanna piss in your cereal you trust your ears or your eyes. Man0 calls the bouncing ball.

:2thumbs:

 

[Bhawkins854]

So manometer? I've seen them used at work a couple times before. Hook it up to my breather lines I'm assuming? I've done port and polish heads, oversized intake valves, decked heads jugs, 600 cam, daytona twin tech ignition, custom donnie smith 2 into 1 exhaust. I also noticed Ive began to build up some sort of sludge on my intake valve on the rear cylinder and not in the front? What does this mean? Ran a compression test and I'm at 200 psi on both cyl.

 

[Sven]

Hook it up to my breather lines I'm assuming? I also noticed Ive began to build up some sort of sludge on my intake valve on the rear cylinder and not in the front? What does this mean?

Hook up the one man0 line to the VOES's intake spigot. The man0 needs to have the liquid suck up the tube and then hangs there via vacuum, having that step down plastic [pinhole] plugged in the line. This restricts the fluid from being gulped down. You'll then notice how the man0 becomes very sensitive to the needle's in and out move.

Excess carbon is being over rich with the air screw/low/main out of phase. The air screw is a lean move. The low and main jets are the next move.

1. Low speed pop out the carb is lean.
2. High speed pop out the exhaust is rich.
3. Run lean to be mean.

 

[outdoorsman26]

I would check all your seals on the intake side of the motor before you hook a manometer up, if there is a leak now there will be after you set the bike wit that meter most liikely your intake seals didnt seal, you may also have to go to a 33int jet and up the main as well

 

[BadBrad]

I've read a lot of threads regarding carb/intake problems but never heard of the manometer. Sounds like something that would measure if you're gay or not. Like Matt said, I would start with re-seating the intake manifold with new seals. It can be tricky sometimes to get the manifold to seat properly on both cylinders. With all the modifications you listed, you may need more fuel, so increasing both jets is definitely a possibility. A few others have had the same modifications and may jump in here and tell you what jets they're running.

 

[Bhawkins854]

I've done two sets of intake seals in a month, second set was to be sure there wasn't a leak. If the engine won't change rpms when I spray brake cleaner ( tried WD40, and starting fluid as well) it can't be the manifold correct? Or do I have to use a different method like smoke?

 

[Bowhunter]

I have used the manometer on many of my bikes the "sync" the multiple carbs to be the same as the other carbs. I am not quite sure I understand the use of the manometer in this application. Are you tuning to maximum vacuum?

 

[Bhawkins854]

When my jugs and heads were shaved down I had to grind a cunt hair of material off my intake manifold to get it to line up. This is why I've been focusing on the intake manifold being the problem. Could a guy use o-ring grease to make a better seal?

 

[RRRUFF]

When my jugs and heads were shaved down I had to grind a cunt hair of material off my intake manifold to get it to line up. This is why I've been focusing on the intake manifold being the problem. Could a guy use o-ring grease to make a better seal?

Don't know how much you took off the intake but there is a clearance + or - that you need for proper sealing. If there is not enough clearance there then when everthing heats up it maybe binding. I am not a tuner but just my thoughts here.

 

[Sven]

I've read a lot of threads regarding carb/intake problems but never heard of the manometer. Sounds like something that would measure if you're gay or not.

Only the gay are clueless to carb and FI tuning with the man oh man ho, is your wife's name Fred? LOL

Like Matt said, I would start with re-seating the intake manifold with new seals.

I think he is running all sooty rich?

It can be tricky sometimes to get the manifold to seat properly on both cylinders.

For you it's tricky. I think he cleared the spray test? If I'm wrong, you must go back and read the OP.

With all the modifications you listed, you may need more fuel, so increasing both jets is definitely a possibility. A few others have had the same modifications and may jump in here and tell you what jets they're running.

You're kidding me right? All those mods and now here is my map? Here are my jet sizes? You tune the snowflake with all the mods. It's like saying, here is my condom, use this size when he's a 4X. Catch my air screw?

I have an evo running with both plugs as clean as can be. My rear spark plug is not having any different reading off my one carb. First things first. Get a clue about throttle body tuning, then you slap your head, say, hey, think out of the box or your pile is on the trailer. It did not qualify for the tire burnout. More like, why did you show up with that out of sunk tuneup?

I know I'm learning a lot here. But, can we stay tuned to what the OP has already stated... Now the OP looks like he is clueless and you called him on it. I have to look like a wiseguy now and give you some of your own meds like you sat on his bike kind of, wondering where that rear end on my seat was last? I'm calling you on your walk there, san fran. YOu blew it, gay guy! :roll:

 

[BadBrad]

Sven, You're one full blown cock sucker. My wife's name is Rocky and I'm sure she would whip your ass given half a chance. You're one arrogant mother fucker to be so new to the site. Do you know how it feels when you need to piss reel bad? Come feel me and tell me if I need to. I'll be the first to tell you I sure don't know all there is to know and never will, but you sure seem to have all the answers. A legend in your own mind.

Brenden,
If you modified your intake, you may want to see a machinist that can check the clearance/tolerance of your modification.

 

[pknowles]

Sven, You're one full blown cock sucker. My wife's name is Rocky and I'm sure she would whip your ass given half a chance. You're one arrogant mother fucker to be so new to the site. Do you know how it feels when you need to piss reel bad? Come feel me and tell me if I need to. I'll be the first to tell you I sure don't know all there is to know and never will, but you sure seem to have all the answers. A legend in your own mind.

Brenden,
If you modified your intake, you may want to see a machinist that can check the clearance/tolerance of your modification.

I have been wondering how long it would take The guy seems to know some stuff, just a hell of a way to convey his message

 

[Bhawkins854]

That's what I'm thinkin brad! As much as I don't want to spend another fist full of money on this thing I might have to look into getting someone to square up this manifold so I can rule that out for sure. The way I buffed it down the manifold might not be square, and given the vibrations of this bike that could easily be my problem. Thanks for the input!

 

[outdoorsman26]

heat can be the factor?? try this.... run the bike til it gets to operating temp then spray carb cleaner around and see if ya have any leaks, I also had a 32int and switched to a 33 and the cough is all but gone, is your accel pump set right/ working corectly? you are looking at the porcelain in the center of the plug correct?? these motors tend to like lean, a LIGHT cardboard brown is perfect

 

[Sven]

The quick solution is to used duct tape around a cold spigot(s) in question. Cold, so the tape does not melt with this fast test. In fact, the bike should start up quick, idle and all that. If there is no change between starting, there was no leak to begin with.

 

[DRBarnhart]

The first issue I noticed is the fact I can back my a/f screw all the way out before the engine wants to stumble.

Right out of the S&S Manual:


"If the idle mixture screw is more than 1 3⁄4 turns out after idle mixture is correctly adjusted, it is a fairly good indication that the intermediate jet may be too small and should be changed to the next larger size."

Dennis​

 

[Sven]

Motion Pro - Syncpro Carb Tuner

1. A mechanic said I had a leak.
2. I changed o-rings.
3. I messed with the screw.
4. We have yet to establish a yes or no, is there an air problem?
5. Well, my plugs are sooty, I must have fuel to match my air leak if I am out more than 1 3/4 turns.
6. The more I am out, the more fuel.


A. Is there an air leak?
B. Where is the screw position now?
C. There is not enough lean to damage anything if you hammer the bike, get it hot, now come back, hook up the man0.
D. I am a fuel or air screw, I can be turned open from closed and match all screws that same opening of that 1/4 turn screw.
E. I can turn the screw out 1 full turn. I am going to turn the rest out the same amount and now blend in the full turns till they all match across the board.
F. I can find the highest peak, 1 turn out. I can find the highest peak 1/4 turn out.
G. School is out.

 

[BadBrad]

I watched the How to for the Syncpro and it never mentions that this instrument is to be used to detect a vacuum leak. It only states that this instrument is to be used to Sync vacuum on motorcycles with multiple carbs. If you hook it up to a single carb, how do you know that the vacuum is not correct? Does the S&S Super G always have the same vacuum even after making modifications to the motor to increase compression? From what Dennis said, if there is no vacuum leak and the idle mixture screw is more than 1 3/4 turns out, you need to increase your intermediate jet. Sounds pretty straight and simple.

 

[outdoorsman26]

. I can turn the screw out 1 full turn. I am going to turn the rest out the same amount and now blend in the full turns till they all match across the board.

dude we only have one carb!!! useing a manometer is useless!!!!

try a 33int take it out run it while your out check your main jet as well