QuestionBill I have Honda CB350F which has leaking carburators from overfilling. I cleaned and checked float levels and OK. I notice float valve cocks to side when float hits metal bracket and so when bowl is put on valve is stuck in open position. I can easily hold float up and replace bowl full of fuel and install. But when I drain I will once again have leaking carb. Is valve or seat just worn out? I am unsure what that metal bracket purpose is except to keep float from hanging down and valve falling out. I find it hard to believe valve is that worn but possibly carb is put together incorrectly.
Thanks
AnswerEd, the "bracket" holds the jets in place, using tension from the bottom of the float bowl to push the retainer against the jets, because the jets are only held in with O-rings, not screwed into the carb bodies, as before.
What often happens with these carbs, is that when you put them back on the bike with the bowls empty, the floats hang down so far that it allows the float valve to drop down and get cocked in the float valve seat, keeping it from closing when the fuel is turned on. What I do is to allow the fuel to fill the bowls, until they start to leak, then shut off the fuel, start the bike and then shake the whole bike back and forth on the center stand until the floats force the valves back into place. As long as the fuel level is maintained at/near normal values, then the floats system should work as normal.
The other, rather rare, cause for overflowing float bowls is when the bowl vent passages are plugged up with gunk. The vent system equalizes the atmospheric pressure in the bowls. When plugged up, the fuel just spurs out the float bowls and the inlet vent ports in the carb throat.
Do make sure that the float is installed correctly and that the float level setting is 21.00mm.
BTW... new CB350F exhaust systems are now available from CMS in Holland.
Bill Silver
