Topic: Does float height affect mixture that much?

[benmanuel]

I can't seem to find a lot of references to how float height affects your mixture. I rebuilt the carbs on my 75 CB400F, it's back on the road and I'm just trying to fine tune the carbs, I want to go out and do some plug chops today, but not if something else is slightly off. Dansmc.com says that a higher fuel level will cause a rich condition and a lower level will cause it to be a bit lean.

When I rebuilt them I basically eyeballed the floats and they all just touched the valve needle spring when they were level with the carb body. I haven't had any one of them overflow since the rebuild.

So is this something I should worry about for tuning sake before I move on to plug chops, fiddling with needles/jets etc?

[Gordon]

So is this something I should worry about for tuning sake before I move on to plug chops, fiddling with needles/jets etc?

Yes, if you want your engine to run it's best and you're going to spend time fine-tuning the other aspects of the carbs, then you need to have the float height set properly, and that can't be done by eye-balling it. 

[Bodi]

The float bottom will be damned close to level when set correctly, I measure to the middle of the float - roughly even with the main jet.
You hold the stack flat as if on the bike and slowly rotate it until you reach an angle a bit past where the float tangs just touch the pins, yet don't depress the springs... it's a three or four handed job, really, unless you have some sort of thingy that can hold the stack. You can then sight down across the bottoms of the floats and see that all four are the same. Once you set the 1 & 4 by measuring you can eyeball 2 & 3 this way, as they are harder to measure. Don't go bananas trying to get them exactly 21mm (as I recall) - they should be close as possible but having all four the same is (IMO) more important that being within .01mm of spec.