cb77 overflow, how does that work?
Andy, it's not an overflow, it's the float bowl breather. Ed (lm) recommends leaving the 'overflow' tubes off as the end(s) can get blocked and prevent the fuel from being properly metered. I prefer to keep mine in place and regularly remove the tubes to check that they're clear. My rationale is that if the float or the needle valve don't do their respective jobs then at least the petrol only stains the road!
+1 on leaving the overflow tubes on (sorry LM). Spent too much time painting the valley cover.
At least on the carbs I've worked on, the bowls are vented through an atmospheric vent drilled into the carb body, AND the overflow tubes, so if the vent is clogged or covered with stuff, the overflow will perform the atmospheric vent function. A microscopic piece of anything can keep the needle and seat from sealing (rust, rubber, scale, dirt, cork, gasket, etc). The leak could therefore go away by itself the next time fuel flows through it. Floats must float to work, take them out and shake them. If you hear a slosh, it's a sinker. Usually a pin hole on the bottom, or a bad spot in a solder joint. Boil a pot of water and dip it in. It will bubble at the leak(s). Get the old gas out of it and re-solder with SAFETY GLASSES and a soldering iron, not a torch or you will pop it open for sure. But why bother, just buy a new float - they're not that expensive.
one of my floats was corroded but seemed ok, i had one in a parts carb that i swapped it for. i set it using lm's instructions and left the other idle etc screws where they were and seems to work ok. been too rainy and busy, hoping to get police vin check before too long, figure i should do that before dropping too much more money into it!
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