Yeah, like Dave said. I have the factory service manual & the Clymer one as well, to give me a couple of options & slightly different perspectives.
Troubleshooting can be a bear sometimes (I'll just leave it at that!!!), but it is generally just a logical progression based on knowledge of how a system works from beginning to end. I wish there was a comprehensive H-D troubleshooting database out there somewhere to refer to, but I haven't found one so far.
Tuning is another thing entirely. Not only are there a ton of variables, each one of these old cantankerous dogs can vary a fair amount, even with the exact same components. There are a few books out there that cover the subject, but I've always been a seat-of-the-pants tuning guy, having grown up wrenching on old cars since I was a teen.
The beauty of the carbureted Big Twin is that it is essentially a very simple motor, so tuning is pretty straightforward. air & fuel go in, get squished, get ignited, and out the exhaust. Understanding how each step works isn't rocket science, and with a little tinkering on what you have, and forethought before purchasing components, it is pretty easy to make good power.
Everyone has different theories about how to make power in these things, but it all comes down to making low-end torque, top-end horsepower, or some combination of both that causes the curves to look pleasing to you as they cross at 5252rpm.
As wise old guys will tell you: "Cheap, Fast, Reliable. Pick any two."
