TOPIC:

I held off posting any of this till I had a good feel of how the bike was running and the fuel mileage after doing this. When you look in your manual it calls for 1 1/2 to 2 turns out on the mixture screw but all the post you will see by club members you will read turn them out to 3 1/2 to 4 turns on the mixture screw. Or that is where you end up. I will say a lot of the guys on here has told me don't do what I did but I am an old drag racer and carb tuning on cars was my best suit. So here is what I did so all of you will know the steps. First get a color tune plug before trying this. Then a very small set of number wire drill bits. Useing the color tune plug set your carbs to make sure where your mixture screw are set when every thing is tuned.After you fine which number drill bit fits the stock jet here is what I found. For every number bit larger than the one that fit the factory size hole you will drop 3/4 to one full turn on the mixture screw. Now to be on the safe side of things do this one step at a time. Don't go two drill bit sizes and say I got it cause I did that with one and had to replace it with a new jet I had in one of my kits. All my mixture screws are now set at 1 1/2 to 2 turns out. I also found that it make the bike pull harder at the low and midrange rpms. The bike is quicker on the low end now and sound more meater. Fuel mileage is 36.6 now and that is even in the hills and dropping gears to hold rpm around 3000 to pull the curves and the hills. I didn't change any of the other jets or move the needles cause my top end was good. I was impressed with the power gain. So was my cousin cause my kz now out pulls his Z14 on the low end and that says a lot.

Hello wrgoo:

So what do your plugs look like when idling for a time? Do they load up at all?

I did not notice if you are running your factory pipe and airbox?

37 MPG doesn't sound too shabby knowing some work hard at getting anything over 35 MPG.

My A-4 gets 38 to 39 MPG combination city/ Hwy, with factory pipes and airbox.

Making the idle circuit fatter with fuel is probably a good workaround on a set of carbs where little to few aftermarket parts are available. (I like your solution)

As you know and read on this forum, the 1.5 turns was a mistake, or I have speculated over the years the early test bikes may have had a larger pilot jet, which may have been cause for the confusion on where to set the fuel/ air screw.

Kawasaki is not known for consistency when writing manuals. That inconsistency also extends to carb modifications and head porting on early test bikes to improve performance.

Thanks for taking the time to cover your carb modification.

T.

I am still factory on the air box and pipes just a after market air filter. To Be honest I have been real slow to make to many changes to the bike because finding part for some of it is a crap shoot. And the carbs is one of those. But I got tired of fighting idle jets that would plug up at a drop of a hat. What I have found by doing this if I have a jet starting to plug up all I have to do now it take her for a ride and lay into to it and the hard pull of fuel thru the jet will clear it out. Now I not saying this is the cure for every thing. You still have to have the carbs working right to start with. The other reason I did this was I just had a feeling even when you had every thing set right at Idle and just off Idle that the bike was leaning out before you got to where the main jet and the needle come in. From the feel of the bike now I was right and the sound of the bike change too. The bike when you roll into it is more throaty and you can not only here it breath but you can feel it. I still am running stock pipes and boy I can't tell you how bad it sounds when you roll into it but its load cause it will turn heads. It breathing and its alive and for an old boy of 62 years this is a rush.