Topic: Sporadic carbleaks

[stormrider]

I have some carb problems on my cb500 k3 -77.  I am hoping for some ideas from you guys on what I can try next, I have been looking on threads here but not found this particular problem.

So, carb 1 and 3 are leaking sometimes. But last week I was riding for an hour without any leaks. Then today (havent changed anything since then) it started leaking as soon as I started it up (now just from nr 1). It did not leak at first, when I turned the petcock on though. But as soon as it fired up it was just freeflow onto the street from carb 1.

I have stopped counting the times I have removed the carbs and finally thought i had gotten the float height right. I have changed the bowl cup gaskets, bowl drain screw o-rings and the float valve things (the spring loaded needle with a rubber tip). Also made a carbsync. Carbs are the Keihin PD 46B, float height should be 14.5 right? Hard to know where to measure though.

What can be wrong? Cracks in the overflow riser? Still wrong float height? Floats not pivoting correctly?

Hoping your input will give me energy to remove the carbs again

[lucky]

I think the CB500 had O rings that could need replacing. When it is cold they can leak and as the engine warms up and expands they seal better.
The engine can expand .004-.019 of an inch.

It they are not the O ring type manifolds try tightening  up the clamps when the engine is warm.

[stormrider]

I solved it. Turns out I had the wrong float height in carb 1 anyway. Thanks for your help.