QuestionI want to know how you can tell if the float in the carbs is set at the right height. I think it is supposed to be set at 26-27mm. My carbs still leak after replacing all rings, seals, needles and seats with new. The floats seem to be in good condition, no holes.
AnswerEric, the setting is 26.0mm it is easier to set the level with a float gauge that can measure both sides of the float at the same time, but a metric scale and good eye will suffice.
http://cgi.ebay.com/ebaymotors/HONDA-CB750-CB350-CB360-CT70-CARB-FLOAT-LEVEL-GAU...
as an example of an adjustable Honda gauge
The level must be checked when the floats tang is just resting on the tip of the needle, but NOT compressing the spring loaded end. It is easier to accomplish this with the carbs on an angle, so the weight of the float does not mash down on the needle tip end. The tricky part is when the carbs are held on an angle, the float pins want to fall out! Put a little grease or vasoline on the pins to help glue them in place, while you are checking all the floats. Be sure that they are not torqued so that one float half is on a different plane than the other side. Float should sit flat on a table, without rocking side to side from being twisted. You should actually note that the floats will be just about parallel with the carb bowl flange when the levels are set correctly.
Check the floats to see if they are heavy from pinholes allowing fuel to make them weighted. Shake them and listen for any fuel sloshing around inside.
An occasional fault is that the brass overflow tubes can split with a hairline crack that seeps fuel out of the bowls at the overflow tube.
Aftermarket carb kits often have poorly cut bowl gaskets and the edges of the floats can hang up on them, as the float rises, causing the float valve to keep flowing because the float has not risen all the way up to shut it off.
Found this link with someone also having issues with CB750 carbs! http://home.att.net/~bobwessner/wsb/html/view.cgi-html2.html--SiteID-776152.html last half of the page.
Hope this helps you out some...
Bill Silver
