Carb float/fuel height using tube method

[rickm]

Hopefully this will be a simple yes/no answer.

When I try to measure the fuel height in the carbs on my Z1000J using a length of clear fuel pipe, I always seem to end up with a pocket of air in the tube between the bottom of the U-bend and the carb drain outlet i.e. the tube is not completely full of fuel.
If I used a black pipe with a clear plastic tube at the end (as in the workshop manual) then I'd be unaware of the air pocket anyway.

Does this matter and will it give a false reading?
If so, why is this happening?

[warren3200gt]

Use a short piece of tube as possible. If you have a air bubble in the tube lift the open end so that the bubble rises to the top of the open end. It won't affect the fuel level in the bowl and then when you lower the open end the level will sort itself out.

[Al]

Alternatively, holding the tube up, blow down the end and the air bubble will go back into the float bowl and what then comes out will be just straight fuel.
AL

[rickm]

Thanks guys.
I did try blowing into the tube and this sent the air back into the carb.
I then wasn’t sure whether this would have an affect on the fuel level in the carb, but I guess it shouldn’t?

[Al]

Check levels and blow down the tube if necessary when the engine is running. It may stumble for a few seconds but will stabilise immediately.
Its a far better way to see what the dynamic level is including any issues with flooding or lack of re-charge which will be instantly apparent.

AL

[rickm]

Nice idea, thanks

[moizeau]

I did as Al said, partially fill the carb, turn off the fuel supply, blow down the tube to get rid of the air but leaving some fuel visible, then turn the fuel supply back on.