Originally Posted by
JDNSW
The top of the Zenith can be removed with the carbie in place. Undo the fuel line and choke cable, and the air hose from the aircleaner. Disconnect the throttle to choke link, taking care not to lose any bits.
Then undo the screws holding the top on - note which came from where, from memory the lengths are different. Lift the top off. This gives access to the bowl and all the jets. The float level can be checked and if thought to be necessary, you can easily remove the emulsion block by undoing two screws and the needle valve. The float is removed by pushing out the pivot pin.
Take particular care with the O-ring that seals between the two parts - damage to this or dirt on the seat accounts for 90% of issues with the Zenith.
If the top is warped, it may cause leaks between passages or fail to seat the O-ring properly. In this case, remove the emulsion block and lap it flat with wet and dry on a piece of plate glass or other flat surface. Make sure that the screws holding the emulsion block are not holding the top apart from the body - burrs on the heads of these can result in their bottoming against the body, again, stopping the O-ring sealing properly.
John