Vespa Small Frame Engine Work

Flywheel side oil seal

There are two oil seals that are located on either end of the crank. These allow the crank to rotate through them but keep the primary compression pressure from leaking out to the transmission or the stator area.

You will need:

  • A new flywheel side seal.
  • A screwdriver or a 90 degree hook tool.

You will need to remove your flywheel and stator plate to gain access to the flywheel side oil seal. Unlike the clutch side, the flywheel seal can be installed with the casing still together and the crank installed. The easiest way to remove the seal is with a large screwdriver but care must be taken to not damage the flywheel bearing behind. Another way to get it out is with a 90 degree hook tool. Either way, you may damage the seal, but you are replacing it anyway so it is no big deal.

The flywheel seal can only be installed in one direction. There is a small circular spring and lip which must face the crankshaft as shown above.

I always ring the area where the seal meets the crank with a thin layer of grease so that it doesn't bind on the crank taper. Fit the seal squarely in the hole and push it down until it is flush with the aluminum casing.

Above is a shot of the flywheel seal properly installed.