Sparks coming out sideways from plug boot

Hi,   1978 KZ650 b3 

I see some sparks coming out from the side of the cyl3's spark plug boot.  Does NOT occur when properly placed on the spark plug but when I pull the boot off.  Is this normal?  

I am sure you are wondering why I would do that, but cyl3 was not firing.  Temp cold compared to others.  I stopped the bike, tighten the boot on the wire, restarted it.

So I was pulling it off while running to see if I got an RPM or engine sound difference seeing the sparks come out sideways as I pull the plug to ground on the engine frame (cyl3). 

Not sure what Ebay purchase I made, or what vendor the plug boots are from.  They are non-resistor style.  They have a rubber end cap.  Hard plastic shell.  Too cheap or normal?

I run with DynaTec S electric ignition with some ebay replacement coils.  Bike suffers from inconsistent plug spark.  Runs around on me from Cyl 2&3, then Cyl4.  I'm think of trying a higher quality.  Any companies in the US?  Thanks for idea.
 

Spark will find the shortest path to earth so not uncommon to arc from the lead or cap when pulled from the plug.
The sparking shows that you are getting power to the cap so the lack of firing on that cylinder is likely down to fouled or faulty plug or fuel related.
Inconsistently fouled plugs may be due to leaking stem oil seals.
You would be best fitting matching Dyna coils and leads ( 3 to 5 ohm ) to get the most from the Dyna 'S' if you are considering replacing the coils etc.

Ah moment.  Using Dyna coils would be a good idea.  The ones I see on Ebay just seem to light weight.  Thanks for the idea.  

Ouch, the Dyna coils are expensive.  

johnmull wrote:

Ouch, the Dyna coils are expensive.  
 

Check out ebay item 165868818007

Thanks for Dyna coil link.   That would be a good one. 
 

johnmull wrote:

Hi,   1978 KZ650 b3 

I see some sparks coming out from the side of the cyl3's spark plug boot.  Does NOT occur when properly placed on the spark plug but when I pull the boot off.  Is this normal? 
 

Yes.  On a four cylinder bike with two coils, two spark plugs are required to 'complete' a coil's output circuit.  If you pull a normally functioning plug wire off, it should shut two cylinders down, unless one of the plug wires is close enough to 'fire' through the engine or frame (neither of which is a 'ground' to the coil output circuit) which is what you're seeing (a sign the coil is working properly).

I got much further on this bike rebuild.  I removed the Dyna S ignition and replaced it with standard points and condenser.  The bike settled down nicely.  Even ignition.  Each cyl same heat. A nice loping sound.  I think the Dyna S fires off the ignition too quickly for the mechanical advancer for this bike.  Either that or the Dyna S is defective although from Dyna S, it passes their good/bad tests.  Says it is my coil, battery, wiring, etc as the issue.

Anyway....going back old school stabilized my ignition.  I did purchase new Ebay coils.  They test out the same as the prior Ebay ones.  Plug boots also replaced.  Same low mileage plugs though.  The gremlins of plugs working one time then another time no...went away.