I have a new to me 1978 Ducati GTS with Ceriani front forks. (The bike came mostly in boxes of bits so I don't know what 'correct' looks like in all cases.) I am installing the front axle. When I put the assembly together- from right to left side- the axle slides through a stainless spacer washer, the speedo drive assembly, the axle carrier tube, then the large spacer on the left side, then the washer and axle nut protruding through the left fork stanchion. It all goes together fine, and the brake rotors are where they should be, but if I tighten the axle nut beyond a certain point, it seems that the tapered bearings bind and the front wheel no longer turns freely. That can't be right. It seems like there is nothing stopping the axle from being drawn through the wheel frm right to left by the force of the nut compressing. I can't find a Ceriani axle assembly diagram anywhere to check my homework. Am I missing a part? A washer? Any ideas? ( I have backed the axle nut off slightly until the front wheeel turns freely again, locked the axle in place with the pinch bolts, and ridden the bike- it rides fine with no strange front end wobble, but I still can't believe it's meant to be this way.....)
Have you tried it with the brake calipers removed and tied up out of the way? If not it may be the calipers not centred with the brake discs causing them to severely bind. BTW, the wheel bearings are ball races not taper rollers.
Looks like you are getting there... It is not possible to pull the forks together because the right-hand fork bottom is free to slide along the wheel spindle. When you tighten the spindle nut, you are tightening the left-hand fork leg against the speedo drive ( you were correct in replacing that washer - as Rick says, the originals just dish, I had some thicker ones made in stainless). When tightening the wheel spindle, leave the pinch bolt loose, hold the spindle with a spanner and tighten the nut, then the pinch bolt. If you loosen the pinch bolt you will be able to push and pull the right- hand fork leg in and out along the spindle - find the centre point and then tighten the pinch bolt. Be careful that your problen is not connected to the fork brace, they can push or pull the fork sliders apart and make the forks bind.