I just removed and cleaned the carbs in my Honda CM450, it was sitting for 12 years. It was my first time doing this, the info on this site really helped a lot…
The good news – the bike started right up! Ran just like it used to!
The bad news – when I turn the petcock on, fuel starts leaking from the carb vents & drain hose. As soon as I turn the petcock off it stops leaking. (When I first put the carbs back on and turned the petcock on, it took about 5 seconds to start leaking, but now it leaks right away after turning the petcock on).
Any ideas on how I could troubleshoot?
Well, I took the carbs off again and re-cleaned the float needles, even thought they looked clean. Then I realized, when I put it together last time, that the accelerator pump assembly wasn’t right… I had put a rubber boot inside the assembly, when it supposed to go on the outside.
Congrats on the fix. If a bike is leaking fuel out the carb it can really only be a couple things. Either the float needle is dirty, worn, or gummed up or the floats are set too high so the needle never gets pushed closed. Both are simple fixes!