There are two common sources of known good sensors. These are: Milton at RC Extreme Power and Adrian at CH Ignitions. Here are the links:

http://www.rcextremepower.net/ignitions.html

http://www.ch-ignitions.com/

While I have used the sensor from RC Extreme Power, I have not used the one supplied by CH though I have several of the older CH ignitions. Both are excellent companies and likewise, both have participated in this thread.

I have attached photos of the RC Extreme Power sensor, also known as the RCxp sensor. This shows exactly how the sensor comes out of the package. The second photo shows just the small Hall sensor attached to the end of the cable. You will have to polarize and assemble the sensor into its holder then assemble that holder into the curved mounting bracket. The bracket exactly fits DLE and many other engines. I assembled the last one I did using rubberized and thin CA and the whole process from package to engine took less than 20 minutes with maybe another 20 minutes to drag out the necessary parts to time the engine. This is a remove the old sensor and install the new one sort of project. You will have to time the engine.