Spark tester question

I'm looking to by a tester, as I'm working on an old MC and need to test coils etc.

Something similar to this.

http://www.toolsource.com/ignition-...-54392.html?osCsid=ae0pqis6a5nag0rrp9loterkc5


The problem seems to be that the end on the tester, looks like one piece, doesn't look like it unscrews like a spark plug end.

Does anyone know of a tester that has an end that unscrews, leaving just the little threaded tip?

Thanks

 

I just cut the ground off a spark plug. connect wire. If it sparks blue you are good to go.

 

Doesn't that end plug into the spark plug wire? The clip end hooks to the spark plug.

You could just make a simple tester using an old spark plug and neon bulb. Connect the electrode to one end of the bulb, the other end goes to the ground hook.

 

That's what I use. It's not calibrated, but it sure works. I have a big "clip lead" (jumper wire) that I clip on the metal shell of the spark plug and attach to ground on the engine, but it's not really necessary. just makes life easier

 

I figured with my dubious "skills" the tool would be great for the MC coils , as it would tell me if coils are week as opposed to just working or not.
I'd be able to test and compare the different coils outputs.