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Alright, So I have a leak in the rear carb of my beloved bike. I have experienced hydro lock a few times. I pull out the plugs and sure enough fuel shoots out the rear cylinder when I turn it over, and ALOT of it. This only happens if I leave the bike overnight or longer than 8 hours. If I ride it to town and around, it fires up nicely. I've taken the carbs apart and cleaned them and cannot find anything wrong. Needle valves are new on front and rear carbs. Anybody have a list of things to check with carbs? I am not too savvy on them as this is my first time working on a carbureted vehicle. I have taken them off MANY times so no worries there, I just need help tracking down what is wrong with my rear carb. Front cylinder never has any issues or fuel on spark plugs.
Thanks in advance for all your wisdom and advice!
 

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Have you checked the float height of the rear carb? If it isn't set properly one condition is that it will never close the valve and stop the flow of fuel into the bowl so the excess spills from the bowl into the intake port. The other condition is that it will cut off fuel flow too early, not fill the bowl and you end up with fuel starvation at larger throttle openings. Also your petcock is suspect since it allows fuel to flow through the vacuum operated valve (diaphram) when the bike isn't running.
 

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Have to point out for anyone experiencing a gas flooded piston: DONT run the engine until you fix the fuel issue AND change your oil.

A little bit of gas in the oil destroys its ability to hold its pressure between the bearing surfaces. Your oil has changed from 20W40 to 0W1

A sticky float bowl is an easy thing to fix, spun bearings are the end of the entire engine.
 
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