After reassembling the chassis, which you could follow in the previous article, it was time to tackle the engine.
This moped dates from 1950 and is one of the first models in the AV3 series.
As a result, many parts are quite specific to this first series: engine head without a cylinder head gasket, no oil seals in the crankcase, crankshaft journals of smaller diameter so smaller bearings than other AV engines, ignition with coils from the Motobécane Poney, same carburetor, etc.
Firstly, everything is cleaned, ultrasonically cleaned, and glass-beaded. This allows us to work with clean parts and detect any potential problems: breakage, cracks, wear, etc.
In the case of this engine, despite being seized for quite a long and hard time, everything is "salvageable".
In order then, for the engine:
changing the bearings to double-sealed ones to ensure a sealed crankcase (as much as possible at least),
making new crankcase gaskets with the “gasket machine”,
changing the decompressor valve seal to also ensure the best possible seal,
installing new piston rings on the refurbished piston and a honed cylinder.
More complicated is the ignition... the ignition coil is dead and rewinding is possible but expensive.
Again, thanks to the help of the 3D printer, we were able to adapt a new coil into the old ignition system. This allows for a repair at a reasonable cost and, most importantly, provides flawless ignition, which is not often the case on these old machines!
Ignition modification and, naturally, the installation of an electronic condenser.
Furthermore, if you are interested in this “modification kit”, the Workshop can provide it to you, do not hesitate to contact us!
The rest is standard: adjustment of the breaker and advance, changing the spark plug wire, the terminal, and the spark plug.
For the carburetor, there were also some issues. This carburetor is specific, so we had to try to save it.
Soldering the float as it was perforated everywhere...
Ultrasonic and glass-beading of the carburetor, just to clear all the passages thoroughly... hoping that will be enough and we won't have major leaks.
With the parts being clean, varnished, zinc-plated, or re-chromed, the final result is very satisfying:
Now, it remains to be seen if it will work as well as it looks!
To be continued…