Float level and overflow ???'s

So my project kz550 is up and running pretty damn well. Iam just curious as to sett ing float height.

Someone has been in this before and I am not getting any overflow issues. No issues at all with stuttering or bogging throughout the rpm range.

Main question is the overflow tubes. If my fl oat height was set to allow too much fuel into the bowl, would it first come out of the overflow tube or would it run down the intake into the cylinders and drip in the crankcase?

I have been checking for oil level height after every ride. No noticeable change. I know my vacuum petcock is working correctly (only flows freely on 'prime' and only flows when the motor is running in on or reserve), and I do not smell any gas through the oil fill cap.

Only reason I ask is that I have a clear fuel filter inline from the fuel valve/petcock to the carbs. When I stop the bike, there is visible fuel in that filter. If I wait and check the next day, there is no fuel in that filter. I am unable to find any leaks anywhere.

If the overflow tubes are clear and the drain screw areas are totally clear, then the fuel will exit the overflow tube before flooding the engine.
If that area is gummed up or just plain dirty, the overflow system might not work.

Also, if you think about it logically, in order for the fuel to "overflow" into the carb throat, the overflow tube would have to be higher than the carb throat, thus it would be poking up into the carb throat... obviously that is not the case.


Follow the links in my signature for a Tk22 website for your carbs. (It doesn't have the overflow info, specifically, but has a lot of other useful info. Check the maintenance page for setting float levels when the carbs are apart in case you ever have to replace the float valves.)

Evaporation is the reason. When modern fuel evaporates to dry it leaves a residue not unlike varnish which can block the small passages within the carb body. That is the reason so many bikes that have sat over winter need the carbs cleaning before taking them out again.
Not an issue for a week or two but for longer I drain the carbs or run the engine with the fuel off until it stalls to drain the carbs of fuel.

Thanks guys. Yeah, fortunately for me I have a handful of gas stations around that offer ethanol free fuel. I am right there with you though, even with an E-free gas, I still drain carbs on bikes if they will sit more than a few weeks.