KZ900 Rotor To Crank Fit Options

All,

I am currently designing and fabricating an external, Gilmer belt drive alternator for my KZ project being documented in the "projects" section. I am looking for different opinions for one component I am making.

As most of you know, the Z1/KZ900 cranks use a tapered machine fit and a 3mm woodruff key for the stock rotor. I am manufacturing a shaft as shown below.



Now I am having difficulty figuring out a method of cutting the internal key way with a traditional broaching tool. I am wondering if I could get away one of the following ideas:

1. Leave off the keyway and rely on the machine taper, a grade 8 crank bolt, and some Loctite 609 retaining compounds for interference fits. One of the reasons I think this would work, is I don't have nearly the inertia to over come of the stock rotor.

2. Drill from the outside and press fit a pin or set screw that would index the external key way slot of the crank. There would be less surface contact, but as stated above, less inertia to deal with anyway.

Thoughts on this? Les or Leon? Rob (ZED1015)?

Cory

My alt pully just bolts on with no woodruff key.

There's not enough inertia from the pully or alt to spin the taper on the crank.

I just used the taper from an old rotor and pressed it in to my pully center.

Do not use anything between the tapers mating surfaces it will not help, Just lap the taper with fine grinding paste,wash with brake cleaner and fit perfectly dry.

Rob,

Thanks for the info. Did you just machine down a KZ900 rotor or did you use another rotor that had the se taper angle? If so, from what bike did that rotor come from?

Used an old scrap 900/1000 rotor that had loose magnets.