IDLE ADJUSTMENT HELP

[Stimey131]

07-Mastiff
I need to adjust my idle rpm up just a little because when it reaches the idle rpm it drops just below 1000 rpms to a point where my tach starts flashing at me warning me my idle rpm is to low. I look in the manual to make sure I was going to turn the correct screw and it also said how to make adjustments slowly. My problem is that it doesn't seem to matter how much I turn the adjustment screw in either direction it doesn't change the rpms up or down. can someone please explain whats going on and how to fix it. I really need to get the RPM idle correct because the engine die's when I stop if I don't keep a small amount of presure on the throtle. Thanks

 

[mmachine]

Three screws

I'm assuming you have an S&S carb. If so, as you are looking at the carb there are three screws - one on the left (where the throttle cables are), one in the middle (brass), and one on the right (or towards front of bike). The one on the left (towards the back of the bike/where throttle cables are) is the idle adjustment screw. Turning it clockwise increases idle speed.

The middle (brass-colored screw) is idle air/fuel mixture adjustment.

The one on the right (toward front of bike) is the accel. pump adjustment.

 

[BroadBand]

Carb ID

07-Mastiff
I need to adjust my idle rpm up just a little because when it reaches the idle rpm it drops just below 1000 rpms to a point where my tach starts flashing at me warning me my idle rpm is to low. I look in the manual to make sure I was going to turn the correct screw and it also said how to make adjustments slowly. My problem is that it doesn't seem to matter how much I turn the adjustment screw in either direction it doesn't change the rpms up or down. can someone please explain whats going on and how to fix it. I really need to get the RPM idle correct because the engine die's when I stop if I don't keep a small amount of presure on the throtle. Thanks

Get your carb back to base settings:
1-Verify carburetor is set to stock settings:
A. Idle Mixture Screw, 1 1/4 turns from lightly seated
B. Idle Speed Screw, ½ turn clockwise from engagement point
C. Accelerator Adjustment Screw, 2 turns counterclockwise from seated

1. Start bike, bring to operating temperature. Close enrichener as quickly as possible.

2. Set Idle Speed Adjusting Screw, clockwise to increase rpm, counter-clockwise to decrease rpm

3. Adjust air/fuel mixture by turning Idle Mixture Screw slowly clockwise until the engine runs poorly. Slowly turn the screw counter-clockwise until it runs smoothly—if you go too far the engine will start to stumble.

4. With engine idling, turn Accelerator Adjustment Screw clockwise until it lightly seats. Snap throttle open—engine should stumble. Turn screw counter-clockwise ¼ or ½ of a turn at a time, until engine responds to throttle twist with smooth, quick response.

5. Ride motorcycle in various RPM ranges, and then try to maintain a consistent 40- to 50-mph. If the engine is popping or sneezing in the air cleaner it can indicate a lean condition. If you notice stumbling or sputtering it can indicate a rich condition

6. Replace Intermediate Jet as necessary—smaller is leaner, larger is richer. Adjust Idle Mixture Screw and Idle Speed Screw as required.

7.To test the Main Jet, do a high gear roll-on from 50-mph to 70-mph. If the engine back fires or breaks up in the carb, increase the Main Jet size .004”. If the engine is flat or will not accelerate, decrease the Main Jet by .004”.

8. After changing the jets, test ride the motorcycle. Continue re-jetting and adjustmenting until optimum performance is achieved.

Note: Drag or straight pipes can prevent you from obtaining optimum carburetor performance.

 

[New Boots]

When you do make adjustments, don’t twists very hard when it seats or you will screw up your carb

[ame=http://www.youtube.com/watch?v=8mDU3MRmm9A]S&S Super E&G Carb Basic Setup - YouTube[/ame]

 

[9secondsflat]

thanks for posting, I didnt have an idea what all the parts that make up the carb were called....always been a FI person

 

[Sven]

Poor idle = Low compression.
What is the compression?

Say the compression is a given. Has the bike been sitting?
This can clog jets or partially both low and main.
This sitting for awhile is another variable.

Intake boots can suck air, cause 14.7 to enter [after] the carb = No gas or first in wins the air to fuel ratio change.

A slight tight valve would be a hard to start when cold, worse when hot?

1. When it's hot, it needs more fuel. That eliminates the valve, if we only knew compression. Chase tail is the number one answer back. And no thumb over plug hole. That is considered cheating.

2. Can't be the carb. It idles all the way down to where it wants to idle, meaning, it revs and can hold an idle if you keep the process of elimination going.

3. I'm going with air boots leaking. Has to overcome the air leak with more fuel throttle opening. That pulls more fuel until it overrides the tiny leak. Is this with electronic ignition and a vacuum type sensor? VOES style?

 

[BigDogBro1]

The short version: Just turn screw #1 CW. :up:

 

[2004BC]

Poor idle = Low compression.
What is the compression?

Say the compression is a given. Has the bike been sitting?
This can clog jets or partially both low and main.
This sitting for awhile is another variable.

Intake boots can suck air, cause 14.7 to enter [after] the carb = No gas or first in wins the air to fuel ratio change.

A slight tight valve would be a hard to start when cold, worse when hot?

1. When it's hot, it needs more fuel. That eliminates the valve, if we only knew compression. Chase tail is the number one answer back. And no thumb over plug hole. That is considered cheating.

2. Can't be the carb. It idles all the way down to where it wants to idle, meaning, it revs and can hold an idle if you keep the process of elimination going.

3. I'm going with air boots leaking. Has to overcome the air leak with more fuel throttle opening. That pulls more fuel until it overrides the tiny leak. Is this with electronic ignition and a vacuum type sensor? VOES style?

OH MY GOD PLEASE GO AWAY!!!! 9secondflat has already been helped by competent proffesionals, not a gibberish drooling mental patient!!!

 

[Th3InfamousI]

Poor idle = Low compression.
What is the compression?

Say the compression is a given. Has the bike been sitting?
This can clog jets or partially both low and main.
This sitting for awhile is another variable.

Intake boots can suck air, cause 14.7 to enter [after] the carb = No gas or first in wins the air to fuel ratio change.

A slight tight valve would be a hard to start when cold, worse when hot?

1. When it's hot, it needs more fuel. That eliminates the valve, if we only knew compression. Chase tail is the number one answer back. And no thumb over plug hole. That is considered cheating.

2. Can't be the carb. It idles all the way down to where it wants to idle, meaning, it revs and can hold an idle if you keep the process of elimination going.

3. I'm going with air boots leaking. Has to overcome the air leak with more fuel throttle opening. That pulls more fuel until it overrides the tiny leak. Is this with electronic ignition and a vacuum type sensor? VOES style?

I actually see where Sven is going with this. Unfortuantly its lost in his writing style. Maybe he can provide us with some kind of decoder for his writing style as I highly doubt most have any clue what he is trying to say.

He is going 1 direction everyone else is going another. He is going under the assumption that the original poster was adjusting the correct screw, which I I think needs to be determined before we proceed with Sven's recommendations.

Let me try to decipher his language back into a readable format for everyone. I'm not sure I have it all but I got something out of it

For Original Poster:

1. Are you adjusting the correct screw?

If no start there. If that does not fix proceed to Sven's recommendations:

2. Does it only idle funny when its hot?
3. In the first picture there is a black boot on the top of the carb, is it still on your carb? If no Buy one and put it back, if yes check to see if its cracked replace if necessary.

 

[Stimey131]

Thanks for all the help. I think I was turning the wrong screw after seing the pictures I'm sure I turned the accelerator pump screw and not the idle screw. So frist I'm going to follow Broadbands guide to get the carb back to basics.

Then if that doesn't correct the problen I will start looking a Sven angle. I kinda understand what he is talking about. I'm not sure how the compression works into it. My compression according to S&S is supposed to 11 to 1 or real close. I called S&S and asked their tech guys what they recomended to increase the performance of the 117ci. They told me to get 40 thousandths shaved off the bottom of the cyclinders and I sent them the heads to get them to do there thing to to them. I also had the carb rebuilt and jeted. I hadit rebuilt because I was trying to eliminate the chance of air leaks. I'm going to work on my bike tomorrow and i let everone know the results. Thanks to everyone.

 

[Th3InfamousI]

Thanks for all the help. I think I was turning the wrong screw after seing the pictures I'm sure I turned the accelerator pump screw and not the idle screw. So frist I'm going to follow Broadbands guide to get the carb back to basics.

Then if that doesn't correct the problen I will start looking a Sven angle. I kinda understand what he is talking about. I'm not sure how the compression works into it. My compression according to S&S is supposed to 11 to 1 or real close. I called S&S and asked their tech guys what they recomended to increase the performance of the 117ci. They told me to get 40 thousandths shaved off the bottom of the cyclinders and I sent them the heads to get them to do there thing to to them. I also had the carb rebuilt and jeted. I hadit rebuilt because I was trying to eliminate the chance of air leaks. I'm going to work on my bike tomorrow and i let everone know the results. Thanks to everyone.

I kinda guessed you were adjusting the incorrect screw. Good LUCK

 

[Stimey131]

I followed the directions to get my carb back to basic, but I had a problem when I got the accerlerator pump adjustment screw. I turn it in until it lightly seated then went 2 turns and went for a short ride to make sure it was good and warmed up. I could tell on the ride that if i cracked the throtle it seemd to stumble a little, so when i got back I set my idle and now it idle great. The problem was when I turned the accelerator pump screw back in to were it was lightly seated. I cracked the throtle and it rev up just fine, when in the video he did this it sound like it was just about to die, but mine rev up great with it all the way in, so i cracked the throtle about 4 times and it just kept reving up great, but in the video he turned it back out 1.25 turns. I set mine at the 1.25 turns until i get some feed back as to what I've done wrong. I took it for another short ride and cracked the throtle a couple of times and it seemed to be OK, but I haven't had a chance to get on a nice straght open road to really let it loose yet and I'm sure when I do that I will be able to tell it's not right yet.

I do recall the last time I did cut it loose that at about 90mph it did seem to have a quick couple of sputters as it was pulling hard still, I kept in it and shifted to 6th somewhere near 105 tp 110 and was still pulling strong, I was getting that a sputter when at WOT, but if i back the throtle down 3/4 turn it was fine. I didn't really worry to much about it because I rarely ever ride at those speeds anymore, but could that hace somthing to do with my carb not being dialed in correctly or is that something else.

 

[Th3InfamousI]

I followed the directions to get my carb back to basic, but I had a problem when I got the accerlerator pump adjustment screw. I turn it in until it lightly seated then went 2 turns and went for a short ride to make sure it was good and warmed up. I could tell on the ride that if i cracked the throtle it seemd to stumble a little, so when i got back I set my idle and now it idle great. The problem was when I turned the accelerator pump screw back in to were it was lightly seated. I cracked the throtle and it rev up just fine, when in the video he did this it sound like it was just about to die, but mine rev up great with it all the way in, so i cracked the throtle about 4 times and it just kept reving up great, but in the video he turned it back out 1.25 turns. I set mine at the 1.25 turns until i get some feed back as to what I've done wrong. I took it for another short ride and cracked the throtle a couple of times and it seemed to be OK, but I haven't had a chance to get on a nice straght open road to really let it loose yet and I'm sure when I do that I will be able to tell it's not right yet.

I do recall the last time I did cut it loose that at about 90mph it did seem to have a quick couple of sputters as it was pulling hard still, I kept in it and shifted to 6th somewhere near 105 tp 110 and was still pulling strong, I was getting that a sputter when at WOT, but if i back the throtle down 3/4 turn it was fine. I didn't really worry to much about it because I rarely ever ride at those speeds anymore, but could that hace somthing to do with my carb not being dialed in correctly or is that something else.

Not sure what video you are talking about

Adjust your carb in your drive way. You should start at stock settings, set your idle first! You work from the far left to right, next is the fuel/air which you turn in until engine stumbles and back off till engine runs smoothly.With engine idling, turn Accelerator Adjustment Screw clockwise until it lightly seats. Snap throttle open—engine should stumble. Turn screw counter-clockwise ¼ or ½ of a turn at a time, until engine responds to throttle twist with smooth, quick response.

S&S Cycle | Carb Quick Guide

You can do that all in your driveway, before you take the bike out Just take your time and listen to your engine she will speak to you :2thumbs:

 

[stlmikie]

If it is stumbling at WOT you may have a lean condition too.

 

[Stimey131]

Well i went back to try this morning and went throught steps of the accelerator [ump adjuster and this time when i losed to a loght seating it did stumble when i craked open the throtle. I turned it a quater of a turn until it was reving smooth and took it for a ride, but once again at at WOT in thrid gear it stumbled. So I got ogg at the next exit and gave it another 1/4 turn and this time when I noticed if I just craked the throthle all the way open as i run throught the gears it would still stumble but if I ease up the RPM's then it ran like a champ. So I've got to be real close to having it dialed in. I'm thinking it provbable needs a slightly larger jet. I want to thank everyone again.

 

[stlmikie]

At Wot the stumble is for sure a lean condition. Take it up a size and see where your at.

 

[Pittpup]

Just to make sure, you're not at the point of hitting your rev limiter now, are you? Is it stumbling when it's really getting wound out?

 

[Nukeranger]

If it ever ran good, I would replace the jets. Buy several different sizes so you can experiment. I think your jets are clogged.

 

[K9Anniv]

Great info! Never understood why BDM put a carb on a 15th Anniversary Model K9, but in hindsight now...glad they did! It's something I can at least work on and adjust on my own, and this info will be very helpful! Thanks for posting!

 

[Th3InfamousI]

Just to keep this thread complete and relevent he sent me this in PM:

the video i was refering to was the one that someone had posted on the thread about idle adjustment help. Which that was me. my problem is i did everything just like you described except when i got to the accelerator pump adjusment screw i turned it in until it lightly seated gave the throtle a a good twist and it just reved up just great, so I craked the throtle again about 4 or 5 times and everytime it reved up just fine no stumble at all. I knew that couldn't be right, becuase I think I remember having to turn in at least 6 full turns to get it to seat, but of course I know that wasn't the correct spot it was at because that is the screw I thought was the idle speed adjusment screw and when it wasn't adjusting the idle I went quite a few turns in both directions trying to get to do something. In other words i had it out of wack. Like I said I set at 1.25 turns and rode it and it di fine at half throtle and below, but when i tryed to open it up it would just stumble and back fire a little. I could tell it wasn't getting enough fuel. Any suggestions as to why it's not stumbling when i close the accel pump screw. thanks for all your input and I've almost got just this last screw.

By the sounds of that is it sneezing out of the carb or is it "stumbling"? Two different scenarios. Sneezing out the carb will mean your lean (need to go up a jet size), and stumble would is more likely to fat and need to go down a size.

This would be a good time to drop the float bowl and figure out what size jets you are running.