Topic: carb leaks out the overflow on #4 carb only any ideas out there

[Don Jones]

I just bought a 1969 Honda CB750 KO and the #4 carb is constantly running gas out the bottom. It is driving me crazy. I can"t find parts for this thing either.thought oh it's a Honda parts everywhere and cheep but not for this thing. can anyone with experience in this bike put on the right course. please

[Gordon]

Tap the float bowl with the handle of a screwdriver.  Parts are plentiful and readily available.  Take a look in the FAQ for an ongoing list of suppliers. 

[mlinder]

Also, the overflow tubes crack. Happened on one of my KO carbs too. Some people put shrink wrap on em. I just soldered it.

[BeSeeingYou]

Sounds like a stuck needle valve, worn needle valve , or leaking float.  Easy to replace and parts are available from the many online sources.  Are the floats from the K0 copper?  If so they can develop hairline cracks or pinholes and allow gas to seep in and sink the float.  This happened on my XS650 and looking at the parts diagram they look like the same or similar floats.

[tramp]

run the bike
shut off the gas
just before the engine shuts down, turn on the gas
kinda flushes the system out

[78 k550]

I couldn't get 1 and 4 to stop leaking. I put new drain tubes on and it fixed my issue.

Paul

[nickjtc]

I had the same problem with the single carb on my '79 XT. Turned out to be a tiny bit of dried up fuel line schmutz trapped between the tip of the float needle and the seat. Cleaned it out, replaced the fuel line and everything was tip-top.