Copyright WWW.DBBP.COM | updated 27-December-2018

Part 7, Assembly & Testing

For testing I used a Harley Davidson #3 spark plug. Thee are various moden spark plugs with the same dimensions. The original XA spark plug had a different size hex and is no longer available so I changed the hex size in my plug caps to a more regular size.


The HT lead is stripped over a length of about 3/4"or 19 mm, then the copper is twisted and folded once. The copper will be clamped between the coils of the the HT (High Tension) Lead has to go into the upper shield before the upper and lower shields are joined. The O-ring holds the HT lead in place after the ring is tightened.


I did a final testfitting on one of Willem's XA motors to determine the correct length of the HT lead, left them a bit longer just to be sure.


Finally I made a little test setup to make sure the spark plug would actually spark, which it did ofcourse! As the HT lead is quite thin (5mm) I made a little copper sleeve as the connection in the universal coil was 7 mm. A bit of heatshrink would also have worked, as long as the copper of the HT lead touches the inside of the coil connection. This was a fun project, I learned several new skills and enjoyed making these, and actually sold all of them as well! Maybe I will need to make a second batch...