You need the stepped spacer, (usually two spacers that fit together on the step, one wide, one narrow) it's the right diameter to hold the gearbox in place.
You answered your own question when you stated your washer stack/spacers allow the sprocket to ride right over.
The spacers rotate with the sprocket, on the engine side of them you need to make sure they butt against the bearing race and don't hit the engine case and drag on it.
|