How Many Turns for the Idle Mixing Screws on KZP?

1987 Kawasaki KZ1000 Police - Idle Mixture Screw (or fuel screw?)

From what I can see in my Clymer manual these are sealed at the factory with a metal cap for the US models but does anyone know how many turns these should have?

My mechanic is working on my bike right now and it is running rich when it's cold outside. Spark plugs are black, etc.

#3 in diagram below \/




Thanks in advance!

I would start at 2 1/2 turns out.

If we were tuning single cylinder bikes this would be pretty easy but there's four of them. I've read a couple service manuals and they get really vague when it comes to this topic. Just my opinion here, watch your tachometer and tweak the screws until the idle speed increases. (Warmed up engine of course) if anyone else has an answer please share. Good luck, it may take you a few sessions , I'm still adjusting mine. They're pretty close but I always feel like I've made things worse when I'm done.
Good luck, don't give up and report back when you get them right!
Rich

A Colortune is very helpful in adjusting the fuel screws.

ThatGPzGuy wrote: A Colortune is very helpful in adjusting the fuel screws.

On a scale of one to ten, how helpful would you say it is? I have one and I would rate it at about a 2. Better than nothing, but not really helpful at all in terms of getting the mixtures dialed in for either best economy or best performance. Do you know something I don't?

If you put a set of vacume gauges on and adjust the mixture screws till you get the greatest vacume , wouldn't that be the way to go about it? Then sink them and you're done ya? It's been a long time since auto class in high school!

jackleberry wrote:

ThatGPzGuy wrote: A Colortune is very helpful in adjusting the fuel screws.

On a scale of one to ten, how helpful would you say it is? I have one and I would rate it at about a 2. Better than nothing, but not really helpful at all in terms of getting the mixtures dialed in for either best economy or best performance. Do you know something I don't?

Probably not. I have to compare it to what I used to do which was put them all at whatever I was told the factory setting was then try to figure out why I was getting a lean surge or had no power on top. With the Colortune I can back the screws out until it's running fat and then slowly dial it in until I see a nice blue flame. Is it tuning for maximum anything? Probably not, but since I did that with my GPz it has never run better.

I have discovered that optimal mixture screw setting were all diferrent in my kz750. Don´t remember precisely each one, but take this for example:

Cylinder 1 --> 2 1/2 turns
Cylinder 2 --> 2 3/4 turns
Cylinder 3 --> 2 turns
Cylinder 4 --> 2 1/4 turns

I have the Colortune, it is usefull. But I thinks is better to hear the RPM change when adjusting the misxture screw.

Bike have never ran better.

Jussumguy wrote: If you put a set of vacume gauges on and adjust the mixture screws till you get the greatest vacume , wouldn't that be the way to go about it? Then sink them and you're done ya? It's been a long time since auto class in high school!

Yeah, that works too and is the most accurate way I've found to do it without an EGA. However, it's still a situation where you have like a 1/4 to 1/2 a turn range where the vacuum reading is the same (just due to the sensitivity of the measurement ) but the mixture (and performance) is not. So you're still left just 'in the ballpark' of the correct settings.

Hi jackal berry
The story I read said to get max vacume and then turn the screws in about a 1/4 turn and call it good. I'm excited and want to do my carbs again!
Crazy!!!

Getting the highest vacuum is a tried and tested method of setting the idle mixture. One thing to be aware of is if you have air screws, or ones that control fuel flow, when giving it that final tweak, I believe that should be an 1/8 or 1/4 turn to the richer, from maximum vacuum, which would be turning air screws in and turning them out if the screw controls the air flow. I have bikes with both these types of carb setup, so have to be careful to think what I'm actually doing when I make adjustments or I can find myself wondering why it's doing the opposite of what I expected when I turn the screw. The downfall of using vacuum gauges is when you use the damping screws to get a steady reading, it also makes them slow to respond to small changes, so you need to use as little damping as you can and move the screw a little, and then wait to see what happens with the vacuum.

Get the screws in the ball park. 1 1/2- 1 1/4 etc. Adjust in small increments in/out 1/8 turn each time. Wait ten seconds for the carb to catch up then try again until best idle. I then raise the RPM's to about 2800 and listen for a miss and dial it out if I can.
Steve