Mikuni 34mm

I need to know about my jet needles, are they supposed to be loose inside the slide or not?

Mine have a plastic piece that holds the needle down in the slide. The spring holds it all in place.

650ed wrote:

TexasKZ wrote: The correct way to set the fuel height is with the clear tube method. There are several threads with tutorials on this site and the procedure is described int the factory shop manual. If you want a free copy of the manual, pm me your email address and I'll send you a copy. The float height measurement is only to get things in the ballpark prior to doing the clear tube method.

+1 The clear tube method is the only accurate way to set fuel levels. Ed

Amen.

The perfect dry float height measurement is whatever measurement results in the correct fuel level as evidenced by the clear tube test.

The dry float height measurement is wrong if it doesn't result in the correct fuel level as evidenced by the clear tube test.

Fuel level is the critical element in carb function.
As long as the fuel level is correct, the dry measured float height is inconsequential.

When each of the four carbs has the correct fuel level as evidenced by the clear tube test, it's not unusual to see variances among the dry measured float heights.

The fuel level specification is often 3 mm below the edge of the of the carburetor body.
Such as KZ900 (26mm carbs).

The FSMs for different models provide the specific measurement range for an acceptable fuel level.
For example, some models may range from 2.5~4.5 mm below the carburetor body.
Such as Z1 (28mm carbs).

1978 KZ1000-A2 (26mm carbs) 3±1 mm
1978 KZ1000-D1 (28mm carbs) 4±1 mm
1979 KZ1000-A3 (28mm carbs) and 1979 KZ1000-D2 (28mm carbs) 4±1 mm

So why goof around with the dry float height measurement?
Because it may sometimes be useful as a preliminary ball-park setting before later fine-tuning the fuel level by performing the clear tube test.

When the carbs were brand new, and before the now aged float mechanisms got worn, bent and banged, the dry float height measurement was more likely to result in a fuel level being closer to specs.

Of course, the "tang" adjustment on the float mechanism is used to achieve the correct fuel level as evidenced by the clear tube test.

Good Fortune!

Thankyou Patton,but I did a clear tube test on the carbs while on bike, it seems to be whithin the specs plus or minus 3 mm from rim,so I no longer feel it is a float problem anymore, I have spark on all cylinders, cylinder 1 exhaust pipe is hot, cylinders 2,3,4,are cold.Bike is running only on one cylinder at about 2000 rpm, when given throtle there is no response, so I suspect that either somewhere they are still plugged up and need to be cleaned again or wasnt sure if the jet needle is to be set firmly on that piece of plastic that holds it inside the slide. The picture in the tutorial has a slide placed upside down on a table and needle is still there upright, if I turn my slide upside down, the needle will fall off, again when I spray carb cleaner in main jet, it should be exiting somewhere?. Thanks again.

With regard to securing of the jet needle inside the throttle slide, there may be a circlip as shown in the pic from the mentioned tutorial. (The enlargement is embellished to help identify the circlip).






Good Fortune!

Thanks for the picture,I have the needle, the slide, and the round plastic the needle goes through that fits perfectly in the slide, I am missing the rest, are my carbs toast, or can these pieces be purchased and carbs restored ? Perhaps its why I am having such a difficult time? I remember seeing a diagram of carburetor like mine, here in a thread somewhere and cant seem to find the diagram again, it shows when you spray cleaner in one hole it should go out in another hole. Thankyou for your time and patience Patton.

The needle goes in first. Then the plastic piece and the spring. If you have the plastic piece in first the needle is gonna be WAY too high! Your last post sounds like you may have it the other way. Just sayin :laugh:

Thankyou for your reply Jonarmstrong, now it all makes sense. I put them back the way I found them.Plastic first, then needle,then spring. Looks like P/O was in there before me and messed them up. When I bought bike, it did not start, so I knew the carbs were gummed up, what I did not know was that they were re assembled incorrectly, however I am still missing a few plastic pieces and circlip that are shown in the picture Patton sent me, I wonder if I can get this carbs to work without the missing pieces, or if Sudco or somebody else carries them?

I've got some of the plastic pieces. How many do you need? I can mail them to you. My carbs don't have a circlip the spring holds all that down.

Well I am going to need 4 and that is very generous of you.I will send you PM.

Here's the diagram from kawasaki.com that doesn't show a circlip, but does show and describe part #5 as a needle set screw.





Good Fortune!

Patton wrote: Here's the diagram from kawasaki.com that doesn't show a circlip, but does show and describe part #5 as a needle set screw.

Good Fortune!

The carb you have posted here looks like the Keihin CV's I had on my '80 KZ750E1.

The butterfly choke plates are not on the Mikuni CV's if I remember right.