adjustment

73 Z1 with 28mm Mikunis ,? I've seen two methods of float adjustment , not sure about which to use, opinions ???

stonemaster wrote:

73 Z1 with 28mm Mikunis ,? I've seen two methods of float adjustment , not sure about which to use, opinions ???

One important carb setting objective is to achieve proper fuel level inside the float bowl.

The float height is adjustable in order to achieve proper fuel level.

The best method to determine actual fuel level inside the float bowl is the clear tube test.
Clear tube test will show whether fuel level is too high or too low or within spec (regardless of measured float height).

I know of only one method of float adjustment (meaning float height adjustment) -- and that is by bending the tang that presses against end of the float needle.

The FSM's usually describe a method of measuring and setting float height with the carbs upside down on the workbench.
This is supposed to result in correct fuel level, but often doesn't.
Even with exact same measured float height on each carb, the actual fuel levels may vary among the carbs.
This is presumably due to slightly different float buoyancies, float functionings, etc.

To determine fuel level --- perform the clear tube test.

To change the fuel level --- bend the float tang (which changes the float height).

Good Fortune!

yea i had come to that conclusion, this carb is new to me, I checked out the OEM tube tool and 70 bucks sheeeeiiittt, so i went to Lowes plumbing section and made my own for about 4 dollars,

stonemaster wrote:

yea i had come to that conclusion, this carb is new to me, I checked out the OEM tube tool and 70 bucks sheeeeiiittt, so i went to Lowes plumbing section and made my own for about 4 dollars,

That's a good solution to replicate the factory tool.

Another alternative is to acquire a length of clear flexible tube slightly larger than the drain hole, and "self-thread" it into the hole. Might sometimes be a little faster than using the screw.

A tip (courtesy of wiredgeorge), when performing the clear tube test on the work bench --- only one float bowl screw is sufficient between tang adjustments. Which saves some time screwing and unscrewing.

Good Fortune!

EDIT -- 1973 Z1 carbs have large drain hole on bottom of float bowls. Adapting the smaller diameter clear tube without a fabbed screw-in fitting, may be via inserting the tube through a cone-shaped rubber plug which fits snugly into the drain hole.

good one on the bowl switch
I got a plastic, threaded fitting with a 90 degree barb connection, file off threads and used plug threads to thread into the plastic, then i attached the clear tubing

If applicable, may disregard any minor leakage during testing.

To alleviate another possible concern, and regardless of how the clear tube connects to the drain hole, some minimal fuel leakage during the testing from the float bowl gasket or where the tube fits onto the drain hole, won't invalidate the test, so long as fuel is entering the float bowl faster than it's leaking out.

Good Fortune!

If you set the float heights carefully first, the wet check should be a confirmation of the fuel level.

Here's a set of my VM28's off a Z1A

If you set the float heights carefully first, the wet check should be a confirmation of the fuel level...

Not always, though. I meticulously set & checked mine dry using a metric pocket ruler, then did the Service Fuel Level check: all 4 were different. So I redid them wet. The carbs & floats were in very good condition.

thanx alot guys,