CDI Units (Cheap, and programmable!)
 

I got an aftermarket CDI unit for a Kawasaki KLR for 1/3 of the price of the OEM Kawasaki CDI unit from this outfit in the Czech republic.. They do a bunch of other bike models as well.

dccdi-p ('http://www.ignitech.cz/english/dccdip/dccdip.htm')

While the web page is a little hard to read sometimes, the stuff they make works a treat, and is cheap (major bonus!). It plugged straight into my Kawasaki KLR, and is even programmable (for performance, fuel economy, fuel octane, etc), via a serial port (and what looks like a regular USB port). The software is Windows only, but for what I got for my money, I wasn't exactly complaining!

The guys I dealt with were Jan and Jiri, and both were very helpful.

I'll report back on the durability of the unit in a while, and if I encounter any issues with it.

There is a simple non programmable one for Enfields and the like at £26.50
will work with any 12v points ignition vehicle ( may have troubles at high revs with 6 cylinder machines)