My 1978 Peugeot 103 leaks gas out of the muffler when I turn the petcock to the 'on' position.
I suspected that it was because the float needle wasn't cutting off the gas, but I have dissected and reassebled the carburator multiple times with no luck. The float seems to move freely.
The bike won't start even though there is a healthy spark. Occassionally it will run for a second or two, but then die. Once i put the petcock in the on position gas begins dripping out of the muffler after about a minute.
One suggestion was to slide the float lower on the needle. But this float has a needle that is fixed in position.