Before the mid 80s motorcycles used points type ignition systems. The purpose of the points was to complete the elecrical circuit at precisely the right moment to fire the spark plug and ignite the compressed fuel in the cylinder. There was some time of mechnical link that connected the points to the cam shaft so that the contact would complete the circuit when all the valves were closed and engine was at top dead center. More on How Points Work
The system worked well and was fairly simple. However, the contact often were fail, become corroded or need to be adjusted. If you talk to anyone who rode bikes alot before the 80s they'll often talk about carrying a extra set of points during log rides because it was so common to have the system fail.
For my project I did not want to mess with all the work it takes to adjust and maintain a points ignition system. Luckily, a new electronic system is now available that works wonderfully.
the Pamco Ignition System is a drop in replacement for the old points on a Yamaha XS650. This system replaces the original points with a small hall effect sensor. This, coupled with a high output coil make for a very robust and almost foolproof system.
The Pamco System
I completed the conversion on my bike in one relaxed evening in the garage. The instructions that come with the kit are easy to follow and customer service is excellent if you run into any trouble.
One word of warning, you can wreck a coil and the sensor if you do not have the proper fuse installed. I skipped this step and it cost me dearly.