Turn outs - How many are you at?

[Nubian]

Just curious what is the most turn outs one would feel comfortable with before opting to re-Jet.
I'm at 3 1/2, I was advised anything over 4 should be bumped up.

[BA80]

I don't know who advised you to bump up the jets because of the turns on the idle mixture screws but it's completely wrong. There are NO jets that affect the idle mixture by putting in larger or smaller ones. Main jets are only in play from about 1/2 throttle to WOT and pilot jets are only in play at an off idle and taper off up to WOT.

The idle mixture screws are where the carbs get all fuel for idle. The only jets that may affect the mixture screws are the air jets in the airbox side of the carbs.

[Rasputin]

I have to disagree here BA80. When I am more than 4 1/2 turns out I increase my Pilot by one size. Then my turns out reduce to about 2 turns. If this diagram is to be believed then one can see how the pilot would affect the idle.

[DGXSER]

There is a reason we refer to it as the idle circuit. General rule I have always used is above five turns out on the mixture screw bump up the pilot jet.

[BA80]

The size of the pilot jet has nothing to do with the idle. The idle mixture screw is fed by the pilot cicuit but the size of the pilot will have no affect on how many turns on the idle mix screw.

My idle mixture screws are at all different turns when the carbs are tuned correctly. Counting turns is a good way to start a carb tune but all cylinders WILL be different due to different conditions. Valve clearances, valve condition, float levels, many factors control that.

The pilots are in play only at an off idle throttle position.

A LITTLE INFO

[motoman]

The size of the pilot jet has nothing to do with the idle. The idle mixture screw is fed by the pilot cicuit but the size of the pilot will have no affect on how many turns on the idle mix screw.

My idle mixture screws are at all different turns when the carbs are tuned correctly. Counting turns is a good way to start a carb tune but all cylinders WILL be different due to different conditions. Valve clearances, valve condition, float levels, many factors control that.

The pilots are in play only at an off idle throttle position.

A LITTLE INFO

Fuel levels in bowls biggest factor affecting idle-mix setting. Idle up to approx. 3800rpm is in the pilot circuit. The earlier carbs drawing fuel from both pilot and main circuit in that lower rpm range leave more factors involved I would imagine.

[Rasputin]

The size of the pilot jet has nothing to do with the idle. The idle mixture screw is fed by the pilot cicuit but the size of the pilot will have no affect on how many turns on the idle mix screw.

My idle mixture screws are at all different turns when the carbs are tuned correctly. Counting turns is a good way to start a carb tune but all cylinders WILL be different due to different conditions. Valve clearances, valve condition, float levels, many factors control that.

The pilots are in play only at an off idle throttle position.

A LITTLE INFO

First off the link does not work for me so I can not see what you are talking about. Second is the fact that the three small holes in the carb at the butterflies do play a role in idle. At least half of one of those holes is in action while at idle. As it draws from the pilot circuit for both those holes and the pilot screw the size of the pilot jet simply has to affect it.

[BA80]

The answer to "first off" http://www.iwt.com.au/mikunicarb.htm

As to your second "fact" .......tune it the way you want. I do.

[BA80]

That link I posted does seem to agree with what you say but if you read pages 152-153 (rejetting) of your Clymers manual you will see where I'm coming from.

[motoman]

Both are good 'general' things to follow, specially to the new person. Doesn't follow true pertaining to reactions of CV carb styles though as far as specifics. Good info to steer a person in the right direction as far as basic functions. That bout it tho. BA80's answer fits well. Just some may chase their tail longer than others to get there,(and learn alot gettin' there).

[DGXSER]

Ummm...Yeah....excert from the link posted....
"The pilot circuit has two adjustable parts, fig 2. The pilot air screw and pilot jet. The air screw can be located either near the back side of the carburetor or near the front of the carburetor. If the screw is located near the back, it regulates how much air enters the circuit. If the screw is turned in, it reduces the amount of air and richens the mixture. If it is turned out, it opens the passage more and allows more air into the circuit which results in a lean mixture. If the screw is located near the front, it regulated fuel. The mixture will be leaner if it is screwed in and richer if screwed out. If the air screw has to be turned more than 2 turns out for best idling, the next smaller size pilot jet will be needed."

Seems familiar for some reason. Since our carbs use the screw located near the front, it is the reverse effect, more than a given number of turns out, somewhere in the 4-5 range,equals a larger jet required.

If you think the pilot jet plays no part in the idle, try pluging it off and getting your bike to idle. Let us know how that works out for you.

[skids]

The problem with resetting the floats is that it affects more than just the pilot circuit. The number of turns out will depend on whether you have after makerket pilot screw springs. I have some that are at their limit at about 3 to 3.5 turns out. I would put in smaller pilots if you are 4 or more turns out because you are probably past the point of making any difference with the pilot screw. In essance, I agree with DGXSER

[BA80]

The idle mixture screw is fed by the pilot cicuit but the size of the pilot will have no affect on how many turns on the idle mix screw.

If you think the pilot jet plays no part in the idle, try pluging it off and getting your bike to idle. Let us know how that works out for you.

Ummm... try reading what I wrote and see how THAT works out for you.

As I said, the link I posted seems to agree with what Rasputin said so I agree that I was mistaken there but also if you read the section on "rejetting" on pages 152 and 153 in the Clymers manual you MIGHT be able to understand what I'm saying.