Topic: How do I know if I need to adjust the needle clip position?

[Dimitri13]

Just as the title says, what and when are the symptoms of needing to adjust the needle clip?

I know the basics, it affects the mixture between 1/8 and about 1/2 throttle, and that moving the clip down is richer, and up is leaner. I just don't really know the symptoms of a misadjusted needle.

I believe I've got the best jet and pilot screw settings, but I'm still getting a slight stumble when taking off.

Bike is a 74 550
Stacks
Two Brothers exhaust from a CBR1000
110 mains
38 slows
Pilot screw 1-1/4 turns out
Needle clip stock (4th from the top)
Floats stock (22mm IIRC)
Engine internals stock

I know someone is going to say stock airbox, but I've got it running near perfect with stacks. I just want that extra little bit to keep me happy.

[lucky]

Although you did not actually tell us the plugs look about right, I would leave it alone.
I would not change the position of the clip in the needle because it will affect 1/4 all the way to 3/4 throttle and the change would be way too much.

If the mixture screw will not effect the stumble, then I would go to a #40mm idle jet.

[Dimitri13]

Can't really tell if they plugs look right, I burn too much oil :x

The mixture screw will affect the stumble. If it's in any more than a whole turn out, it'll start popping on idle, and the stumble will be just a tad better. Any more out than it already is, the idle will get progressively better but the stumble will be worse.

The intake is velocity stacks (from DCC/steel dragon)

Haha no that's not my bike. Although I wish it was. Love that seat and tank. Those are the stacks I have though. Plus I'd love some new shocks and a properly sized front tire.

[Deltarider]

Although you did not actually tell us the plugs look about right, I would leave it alone.

+ 1. There's so much raising and lowering of needles in this forum, I don't know what to think of it. It is as everybody infects everybody. Our pre 1977 bikes are filthy old beasts, that can handle A/F mixtures in a pretty wide range. I've raised my needles out of curiosity from 3rd to 4th and although the engine pulls fluidly, there's a too rich transition from idle to a bit above idle now that annoys me. I wish I had shimmed the needles with just a little flat ring instead and had left them in 3rd. When I can overcome my laziness, I will do.
Adjusting needles is a lot of work. You'd better be d@# sure.

[cgswss]

Hows this, I'm different.  First I would do a plug chop with new plugs.  The plug chop is done at high RPM and you don't allow the engine to turn over after so you should be able to get a good reading off you plug insulators

Second, I would very highly recommend going down a notch on the needle (more rich).  What have you got to loose?  Sure its a few hours out of your life, but if you are careful it will cost you nothing and you may find a better running engine in the end.  In my experience pods make the mixture vary.  they are not always lean as RPMs go up the MAY go from very lean to rich and back to lean.  That means you really can't correctly tune for them because you have no way to adjust the fuel map in small enough chunks.

[lucky]

EDIT: Got dimitri confused with another forum member sorry.

[70CB750]

I did go through al the needle settings on my KO.  Change it, ride it, repeat.   It was very educational and helped me decide where to set it at.

With my sandwich air filter and mac exhaust I am at #4 and loving it.

[Dimitri13]

Oh, in that thread, I was just giving the guy something to go off of, so he had some idea of where to start.

[lucky]

I did go through al the needle settings on my KO.  Change it, ride it, repeat.   It was very educational and helped me decide where to set it at.

With my sandwich air filter and mac exhaust I am at #4 and loving it.

What does that mean?
Does that mean you have the clip at the 4th notch down from the top?

[bollingball]

This is one of two different threads about the same bike.

One one thread you told us the bike had.
Bike is a 74 550
Stacks
Two Brothers exhaust from a CBR1000
110 mains
38 slows
Pilot screw 1-1/4 turns out
Needle clip stock (4th from the top)
Floats stock (22mm IIRC)
Engine internals stock

On the other thread "Please help-I'm Carb dumb"

You gave this,
1972 CB500.
Intake stacks with screens and foam covers.
Exhaust. 4 into 1 Yoshimura.
Main jets #100mm (What was the stock size?)
Idle jets #? (What was the stock size?)
needle clip position from the top??? (Stock position?)
mixture screw???

Are we talking about two different motorcycles???

On the first one you said It was burning oil.
I think it needs a compression check since it has stock jets and is running rich with Two brothers exhaust.

Are we talking about two different motorcycles?

And your point is?
Ken

[lucky]

This is one of two different threads about the same bike.

One one thread you told us the bike had.
Bike is a 74 550
Stacks
Two Brothers exhaust from a CBR1000
110 mains
38 slows
Pilot screw 1-1/4 turns out
Needle clip stock (4th from the top)
Floats stock (22mm IIRC)
Engine internals stock

On the other thread "Please help-I'm Carb dumb"

You gave this,
1972 CB500.
Intake stacks with screens and foam covers.
Exhaust. 4 into 1 Yoshimura.
Main jets #100mm (What was the stock size?)
Idle jets #? (What was the stock size?)
needle clip position from the top??? (Stock position?)
mixture screw???

Are we talking about two different motorcycles???

On the first one you said It was burning oil.
I think it needs a compression check since it has stock jets and is running rich with Two brothers exhaust.

Are we talking about two different motorcycles?

And your point is?
Ken

Sorry bolingball for that entry I had gotten confused about two similar bikes.
My mistake.

[lucky]

Oh, in that thread, I was just giving the guy something to go off of, so he had some idea of where to start.

OK...I understand now Sorry for the confusion I caused.

[bollingball]

Just as the title says, what and when are the symptoms of needing to adjust the needle clip?

I know the basics, it affects the mixture between 1/8 and about 1/2 throttle, and that moving the clip down is richer, and up is leaner. I just don't really know the symptoms of a misadjusted needle.

I believe I've got the best jet and pilot screw settings, but I'm still getting a slight stumble when taking off.

Bike is a 74 550
Stacks
Two Brothers exhaust from a CBR1000
110 mains
38 slows
Pilot screw 1-1/4 turns out
Needle clip stock (4th from the top)
Floats stock (22mm IIRC)
Engine internals stock

I know someone is going to say stock airbox, but I've got it running near perfect with stacks. I just want that extra little bit to keep me happy.

                                                                                                     So haven't you read enough to know this is why someone will tell you to use the stock air box. Stacks are best suited for wot. You will not be able to tune them as well as the stock box. So there someone told you. If you say you can then back it up with proof a dyno sheet with a fuel map. A butt dyno does not count. I'm not saying you can't get close but you are there. You need a accelerator pump.
Ken

[70CB750]

I did go through al the needle settings on my KO.  Change it, ride it, repeat.   It was very educational and helped me decide where to set it at.

With my sandwich air filter and mac exhaust I am at #4 and loving it.

What does that mean?
Does that mean you have the clip at the 4th notch down from the top?

Correct, 4th notch counting from the top end of the needle.

[Dimitri13]

So haven't you read enough to know this is why someone will tell you to use the stock air box. Stacks are best suited for wot. You will not be able to tune them as well as the stock box. So there someone told you. If you say you can then back it up with proof a dyno sheet with a fuel map. A butt dyno does not count. I'm not saying you can't get close but you are there. You need a accelerator pump.
Ken

Hehe, I've been here long enough to know that Hell, I've even suggested to others to go back to the stock airbox if they want a well-performing bike. I know I won't be able to get it tuned as well as the box. But my butt dyno says it's good enough for me.