1999 kat 600 carb questions.

[Mark600Kat]

I did read Carb 101 and 102 or whatever they were called.

I Have a dynojet kit and pod air filters and a very open exhaust. Including a 750 header on a 600.
My questions is:
throttle all the way up to 3/4 open revs and runs fine. but 3/4 to full WOT it kinda dies.
If im goen down the road and crack it wide open it accelerates but if i let off the throttle a little it goes faster. I think its leaning out past 3/4 throttle.

The fuel mixture screw... should i turn it OUT or IN for more fuel i currently have it 3 and 1/4 turns out form stop.

thanks.

[Kfreak]

I believe turning it out will increase the fuel. This will confuse you...... depending on where the mix screw is located on the carb's, will determine what it will adjust.

[Kreylyn]

I did read Carb 101 and 102 or whatever they were called.

I Have a dynojet kit and pod air filters and a very open exhaust. Including a 750 header on a 600.
My questions is:
throttle all the way up to 3/4 open revs and runs fine. but 3/4 to full WOT it kinda dies.
If im goen down the road and crack it wide open it accelerates but if i let off the throttle a little it goes faster. I think its leaning out past 3/4 throttle.

The fuel mixture screw... should i turn it OUT or IN for more fuel i currently have it 3 and 1/4 turns out form stop.

thanks.

Are you haveing issues with idle?... cause that is pretty much all the A/F screws are going to help with.

Over 1800 rpms your no longer using the pilot system which the A/F screws are a part of. I would look at your e-clip position on the needles, and the main jet sizes for the issue your having with your current setup. Or.. if your just using a stage 1... swap back to the OEM air filter and air box, and it will probably help. Your leaning out because too much air is flowing would be my guess.

Krey

[Mark600Kat]

Are you haveing issues with idle?... cause that is pretty much all the A/F screws are going to help with.

Over 1800 rpms your no longer using the pilot system which the A/F screws are a part of. I would look at your e-clip position on the needles, and the main jet sizes for the issue your having with your current setup. Or.. if your just using a stage 1... swap back to the OEM air filter and air box, and it will probably help. Your leaning out because too much air is flowing would be my guess.

Krey

Yeah it is to lean i believe and i was reading all i could last night. I realize the air/fuel screw doesn do anything past low RPM.

Im running stage 1 because thats all they sell for my bike no 2 or 3.
ITs a 120 jet. The kit comes with 110 114 116 and 120 jets. I have a 750 headers on the bike and barely an exhaust (cut a yoshi to about half length) and im running the individual air filters. I am most certain that its to lean but i cant jet it up any higher. Unless i go to Dynojet.com and order like 142 jets individualy. What would happen if moved the needle up a notch? meaning move the E clip down a step witch would lift the needle up.

[JModified]

If its running good all the way up to 3/4 I would change only the main jets. If it takes care of the 3/4 to wot problem, you can try the needle up 1 more and see how it runs. Dynojet recommends the 4th position on the needle with pods and open exhaust. I just installed the dynojet kit in my 06 750 kat and ended up with 122/s as my mains, 3rd position on the needle. I have a k&n and a moto gp exhaust, basically wide open exhaust.

[Mark600Kat]

Thanks guys. IM taken the top of the carbs off, droppen the clip down one slot and then see how she runs. I still think im gona need a bigger main. 120 is the bigest they gave me. and it only seems to run lean after 3/4 throttle. thats with my open exhaust and pods.

[Kreylyn]

What should happen when dropping the eclip down a notch (raising the needle out of the hole more) is enrichen the main fuel mixture more. It will only do so much though, as it fine tunes what you have flowing out of the main jets. If they are too restrictive, well... can only get so much to flow.

Krey

[Tmod]

Get the main correct and then work down from there on the jetting. With the changes you have made I am sure you are going to need a larger main.

Also the pilot jet does indeed affect the whole fuel range from idle all the way to the top.

Tmod

[Kreylyn]

Also the pilot jet does indeed affect the whole fuel range from idle all the way to the top.

Tmod

Care to explain in more detail how so?...

Krey

[Tmod]

Care to explain in more detail how so?...

Krey

The pilot circuit cannot be cut off as there is no valve or anything to shut it off, Yes there is more vacuum at that port at low throttle openings but when the butterfly's are open and velocity is up it will also draw from the opening. Think of it as the coke bottle effect, Air traveling over that port will still bring some of the pilot circuit into play. Here is a graph that I got from some site awhile back. Feel free to check out any Tuning site, Factory Pro or some others and you will see that circuit does indeed play a role in the fuel curve through the entire range.



Tmod

[Mark600Kat]

Well i needa bigger main. I droped the needle a notch and it ran like ish. so i put the needle back. #3 notch. Like Dynojet says. Took off the pods (individual air filters per carb) and put back on my box with KnN filter. Bike runs perfect.

If i want to run Pods i need a larger main. 120 is to lil. BEcause with pods and 120 its great power to 3/4 throttle. After 3/4 to WOT its ****. Now with the KnN its great all the way to WOT. The KnN actualy resticts the flow of air a bit more then the Pods.

N they dont sell Stage 2 or 3 for my Kat none that i can find anyway. But i can order Main jets from dynojet. Problem is how much larger do i want to go. To large = to rich Not large enough and ill still be to lean. Im thinken like 130-140 area.

The pilot circuit cannot be cut off as there is no valve or anything to shut it off, Yes there is more vacuum at that port at low throttle openings but when the butterfly's are open and velocity is up it will also draw from the opening. Think of it as the coke bottle effect, Air traveling over that port will still bring some of the pilot circuit into play. Here is a graph that I got from some site awhile back. Feel free to check out any Tuning site, Factory Pro or some others and you will see that circuit does indeed play a role in the fuel curve through the entire range.



Tmod

This is interesting... Ill have to look at my Pilot jet and see what size it is. Maybe change it.. Iv been experimenting all day. LOL

[Tmod]

Well i needa bigger main. I droped the needle a notch and it ran like ish. so i put the needle back. #3 notch. Like Dynojet says. Took off the pods (individual air filters per carb) and put back on my box with KnN filter. Bike runs perfect.

If i want to run Pods i need a larger main. 120 is to lil. BEcause with pods and 120 its great power to 3/4 throttle. After 3/4 to WOT its ****. Now with the KnN its great all the way to WOT. The KnN actualy resticts the flow of air a bit more then the Pods.

N they dont sell Stage 2 or 3 for my Kat none that i can find anyway. But i can order Main jets from dynojet. Problem is how much larger do i want to go. To large = to rich Not large enough and ill still be to lean. Im thinken like 130-140 area.



This is interesting... Ill have to look at my Pilot jet and see what size it is. Maybe change it.. Iv been experimenting all day. LOL

For the problems you are having the pilot circuit will not compensate for or would that be the correct approach, Start with the main and work backwards making sure each circuit is set correctly. In my experience with Dynojet kits they really are not calibrated correctly in any area. You will end up playing a game of cat and mouse trying to get this thing running correctly.

Tmod

[Kreylyn]

The pilot circuit cannot be cut off as there is no valve or anything to shut it off, Yes there is more vacuum at that port at low throttle openings but when the butterfly's are open and velocity is up it will also draw from the opening. Think of it as the coke bottle effect, Air traveling over that port will still bring some of the pilot circuit into play. Here is a graph that I got from some site awhile back. Feel free to check out any Tuning site, Factory Pro or some others and you will see that circuit does indeed play a role in the fuel curve through the entire range.



Tmod

I agree.. there is no shut off for the pilot system, so there would be some effect on the full range of throttle control. How MUCH of an effect I guess would be more of a question here. Adjusting the A/F screw is really going to have minimal effect (with in the confines of the bike still idleing properly)... meaning, if it idles right, will any fine tuning (again, with in the range kepping a good idle) of the A/F screw make a major change to the higher rpm range? I don't believe so...

I've always seen it refered to as "Effective Adjustment" for the different ranges.... with the A/F not having any effective change to the higher rpms with in it's properly set range of adjustment for a good idle.

Here is another good graphic on this...



If your issue is higher rpms leaning out... I just can't see an adjustment to the A/F screws being much of a tuning option unless your going to sacrifice the low end and idle to do so...

Krey

Edit : *wow... several more responses as I was typing this... *

[Tmod]

I agree.. there is no shut off for the pilot system, so there would be some effect on the full range of throttle control. How MUCH of an effect I guess would be more of a question here. Adjusting the A/F screw is really going to have minimal effect (with in the confines of the bike still idleing properly)... meaning, if it idles right, will any fine tuning (again, with in the range kepping a good idle) of the A/F screw make a major change to the higher rpm range? I don't believe so...

I've always seen it refered to as "Effective Adjustment" for the different ranges.... with the A/F not having any effective change to the higher rpms with in it's properly set range of adjustment for a good idle.

Here is another good graphic on this...



If your issue is higher rpms leaning out... I just can't see an adjustment to the A/F screws being much of a tuning option unless your going to sacrifice the low end and idle to do so...

Krey

If you are referring to seat of the pants feeling then yes you would not feel the change, If you have any instrumentation then you will see it. In my first post I did say that the pilot circuit is not a fix for the problem here, But it does add to the whole picture. Factory Pro even states in their tuning instructions that the pilot circuit affects high rpm throttle position.

Tmod

[Kreylyn]

If you are referring to seat of the pants feeling then yes you would not feel the change, If you have any instrumentation then you will see it. In my first post I did say that the pilot circuit is not a fix for the problem here, But it does add to the whole picture. Factory Pro even states in their tuning instructions that the pilot circuit affects high rpm throttle position.

Tmod

I think we are agreement here, just nit picking over the wording details...

Krey