clear plastic tube test

1983 KZ750F1 LTD Shaft

I did the clear plastic tube test and found out that the service fuel level is very high on the 2 carbs on the right side of the bike.
A few weeks ago I had gas leaking out of the carbs when i shut the bike off. I ordered a new vacuum petcock and that solved the problem. However after some research on this forum I learned that gas shouldnt leak when the bike is off regardless of the petcock, as long as the floats/valves are properly adjusted in the carbs.
What could it be? A few months ago i had the carbs apart for cleaning and made sure the float height was correct.

Did you use the bench test to set the float height? I tried that, had them all set, and had the same problem. I had to do the tube test to get them set right. Takes a little time to get them just right.

+1 on the bench test being basically worthless. I can't even begin to tell you how many times I tore into my carbs because of float height before I got smart and made myself a clear tube meter.

jon0108,
I've always admired your bike, I have the same model in disarray in the garage right now. She'll never be as nice as yours as the original paint is long gone, but I'm doing my best.

Can I persuade you to add some close-ups to the KZ750 picture Gallery? It sure would help me in my rebuild.

Kent

anarki650 wrote:

+1 on the bench test being basically worthless.

Amen.

What do you guys use to screw in the drain hole to attach the clear tube to? What is the thread size/pitch of this hole?

HerrDeacon,
On the 650 I use whatever size tube I can force fit in the drain hole. It stays in long enough to get the float set.

Some guys will also take a plastic vacuum fitting of slightly larger o.d. than the threaded bowl outlet, and screw the fitting in the bowl. The metal bowl cuts the thread into the fitting as it screws in. Then just attach
the tube.

I am posting pictures from Odd Ivars great site for the KZ400. www.kz400.com

Perfect, thanks OKC. That's a great idea to use plastic and just thread it in there.