Setting the Carb Float Height

[BowlingSS]

The manual says to turn the carbs upside down and check from the gasket surface to the top of the float bowl to be 1.0217. My problem I have my carbs off and all of them are the same but not even close to 1.0 inch. I have a 1980 SG. Does the SG have a different spec on this measurement?

Thanks.
Bill

[motoman]

The manual says to turn the carbs upside down and check from the gasket surface to the top of the float bowl to be 1.0217. My problem I have my carbs off and all of them are the same but not even close to 1.0 inch. I have a 1980 SG. Does the SG have a different spec on this measurement?

Thanks.
Bill

The 80-81 and XJ carbs float settings is 23mm(0.090551).

[BowlingSS]

The 80-81 and XJ carbs float settings is 23mm(0.090551).

Thanks. Should you have to lift the floats where they are just touching the needle before taking measurement?

Bill

[motoman]

Thanks. Should you have to lift the floats where they are just touching the needle before taking measurement?

Bill

Normally not, but if makes you feel any better, tilt the carb bank at slightest angle so floats weight is reduced on float needle spring.
Think you'll find it makes NO difference.

[3Phase]

Bill,

Just let the floats rest on the needles, they're supposed to support the weight of the floats. If you tilt the carburetors sideways you won't be able to tell if the needles and anti-chatter pin springs are good.

To make sure the needles are good, lightly bounce the floats a couple of times and look at the little spring loaded anti-chatter pins in the end of the needles. The pins should all support their floats at the same height and they should not bind, stick or collapse.

Extra work you may or may not want to do:
It's an extra step that requires extra parts and some patience but after you set the float height you should check the dynamic fuel level in the float bowls to make sure the floats are actually, you know, floating and keeping the fuel levels the same in all four carburetors. Dynamic in this case means that you check the fuel levels while the engine is running.

I set the float heights in my 1980G carburetors to microscopically identical measurements and the fuel levels were all different when I checked them with the dynamic test. Go figure, that's why Yamaha went to fuel level specs and ditched the float height specs.

The late-model 1981 XS11s and 1982 XJ11s don't even list a float height setting, they have float bowls with a drain screw and a nipple to hold a clear tube to show the fuel level in the bowl.

The earlier XS11s have a brass drain plug in the float bowl that you have to replace temporarily with four 8mm x 1.0mm brake bleeder screws for the dynamic check. I think they're for a Ford disk brake caliper.

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