Reply To: JAP 2a flywheel removal

[sidevalve5]

H7 is a transition fit, where it’s not a sliding fit, but not a press fit either. The flywheel should fit over the shaft and come off again with very little effort. But have some resistance to rotational turning.

There was no felt seal around the edge of the stator plate.

Believe the engine cowl has never come off since it left the Alcon works. So anything that is unusual was done by the JAP factory or possibly Alcon. The steel key has two grooves either side of it, so was designed to shear if the engine stopped suddenly. Modern engines have an alloy key that does the same. Have you or David seen keys like that on a 2a before, because I have not. Could be that the roll pin mod was specified by Alcon, but only for a short while. If the pulley was tight against the flywheel, the key would not shear as designed. Will take photos of the key and the sheared Villiers crank that I have mentioned in a previous post. That was broken by a pump sucking up a stone.