float adjusting --- older mikuni

[Colorado]

My Clymer's shows a float level tool for setting the level of my IT400 mikuni, but I don't have one, so just used a small carpenter's combination square. But the process in the book is a little confusing.

The book is outside, but I think the setting was something like .71 inches. It has two photos of different carbs, because it covers all displacement ITs of that vintage. One photo has the float level tool illustrated on a carb where the float hinges with the float arm. The other photo is like my carb, where the floats actually ride on pins in the float bowl. It shows the carb, upside down, with lines drawn from the end of the brass float arm and the body of the carb, then arrows drawn pointing to the two lines about an inch away from the body where the float bowl goes.

Does anyone know if that point, about an inch out, is where I am supposed to take my measurement? If I bend the tang to get .71 at the end of the arm itself the measurement taken an inch out will be much greater than .71 (if I took a picture and drew lines they would not be parallel -- they would be widening out at an angle). The Clymer's is not clear about where the measurement is taken, and the text doesn't say that the arrows signify the correct place. Does anyone know for certain how the mikunis with the floats on pins are measured?

I set it at the end of the arm, and the bike runs okay, but sometimes when I turn it off gas will pour out of the overflow lines, though it doesn't run or drip out if I leave the petcock open with the bike off.

Thanks for any help!

 

[Ol'89r]

Colorado.

With the carb upside down and the weight of the float resting on the float needle, measure from the highest part of the float to the float bowl gasket surface. A six inch steel rule works pretty good. Just hold the carb level and sight across the top of the float.

Just my $ .02

 

[Colorado]

Colorado.

With the carb upside down and the weight of the float resting on the float needle, measure from the highest part of the float to the float bowl gasket surface. A six inch steel rule works pretty good. Just hold the carb level and sight across the top of the float.

Just my $ .02

Thanks Ol89r, but it sounds like your talking about the other type of float, where the floats (or float chambers) are attatched to the float arm. All of my other bikes have that set up, and I've always known how to measure them. This carb is different though. If I take the float bowl off, the float (chambers) remain in the float bowl. They ride up and down on pins (thin rods?) with little plastic caps on the top. When they float up the pins as fuel fills the bowl they contact the arm and close the float needle valve, but there isn't any way to measure from the gasket surface to them, because they come off with the bowl.

Maybe I should ask this in the vintage forum, as it doesn't seem to be a common set up any more.

 

[Ol'89r]

On that type of carb you measure from the top of the arm (where the float pins contact the arm) to the gasket surface.

There should be little shiny marks on the arm where the pins ride.