Z1 Alternator Rotor

[Garn 1]

I am having trouble with fitting the magnetic rotor to the tapered end of the crank-shaft of a Z1A.
I have three rotors
Anyway, the problem is two are too loose and one looks as so it might just make it, if I lapp it in and probably do a little machining.
Has anyone an easy solution for this common problem?

I find the loose rotors are bottoming on the large extraction thread at the "small end" of the rotor. To make the loose rotors fit the taper, I was going to bore some of the thread out of the rotor small end, say about 3mm recessed 1 mm depth, so that the tapered shaft can go further onto the taper! Any comments?

RegardZ.

[zed1015]

Had to do that a few times, usually because someone has fitted a rotor off another model that has a shorter taper.
Rotor material is soft and easy to machine.
Only take off the bare minimum or you risk there not being enough thread area left to take the force of subsequent extractions without stripping.

[Garn 1]

Thanks for the reply.... I just had another thought ~ How about I hand-grind a small chamfer at the end if the crank-shaft taper? It only has to be about 1.5 mm X 45 degrees. This should disallow the shaft to bottom on the thread and should not affect the bearing surface in the taper. Any thoughts?

I know I'm going to have to deal with the loss of space between the rotor rear face and the crank shoulder.... which entails the washers and damper etc., however, I will deal with that later.

RegardZ.

[zed1015]

That would work too.
Personally i would avoid altering any unaffected part and only modify the already damaged/worn rotor.
Once done it shouldn't need to come back off and if there is unsufficient thread left for the extractor then a three legged puller could be used as a last resort.
The danger with the 3 legged though is that it can distort the rotor if excessive force is needed on removal.

[Garn 1]

Zed1015, thanks for your advice, however I did take the fast way out and just linished the end of the crank taper, making sure I did not take more than 1.5 mm in the chamfer, bearing in mind there was a small chamfer there already!

It did work and all rotors fitted after a brief lapping with fine valve grinding paste and cleaning.

RegardZ.