If you will be using the retaining compound to bind the rotor to the shaft, you may skip this section, if you wish. See the Parts section above for details on retaining compound.

The photo above shows a stock generator shaft.

The friction-bond between the rotor and shaft must be improved. So next, put a small dab of lapping compound on your finger. Smear it on the tapered portion of the generator shaft, so that the compound completely covers the taper. See photo below.

Tip: The lapping compound I got came with both coarse and fine grits. I used coarse grit compound for the first few rounds. Then I switched to fine grit.

Slide the rotor onto the shaft. Be sure the starter-clutch gear-train is out.

As you apply about 10 or 15 pounds of inward pressure on the rotor, rotate it clockwise about 8 complete rotations.

Then reverse the direction of rotation and do another 8, or so, rotations.

By now, the grinding feeling of the compound should be feeling smoother than initially. If not, apply a bit more pressure and keep pushing and turning until it does feel finer--less gritty.

Next wipe off the compound from both shaft and rotor. Check the shaft and rotor for high and low spots--which will show as a darker or lighter grey color.

Repeat the entire lapping process until no more high/low spots are found. Caution: Do not repeat this process more than 5 to 6 times however, as you may wear the taper down to where the shaft-end contacts the rotor's end-shoulder. This would ruin the rotor's ability to make a strong bond with its shaft. In other words, don't try to get a clean lapping all the way to the shaft's end. Leave the last eighth inch or so unfinished.

Use paint thinner or other solvent to thoroughly clean the generator shaft taper, the rotor taper-hole, the center-bolt, and the shaft threaded hole. See photos below.