look at this one. 2 bearings, a shaft, a key, spacer, 2 sprockets. Their pretty simple. The guy slotted his base to tighten up the forward chain. LOOK HERE:
Building a jack shaft I am told is pretty simple, keeping them in line is the hard part, they always want to twist. And make sure you get high speed bearings.
Thanks for the info on the jack shaft. Here some pics of my bobber. The motor on the blue bobber is a 68 and belongs on the fat tired tri. the motor on the fat tire is a 67 and needs a new set of carbs and a good cleaning and will go back on the bobber. i built the 68 motor 4 years ago and havnt heard it run yet.