Misc: Ignition Unusual sparking at magneto contact breaker assembly. (with video clip)

[Paul Coene]

Recently, the KVF magneto of my Rapide needed a new insulated washer as the old one - probably non genuine - was disintegrated causing radial clearance of the magneto shaft.
After the repair, I noticed a remarkable sparking which I could capture on video. On the first clip, you can see a couple of times underneath yellow flying sparks. The second clip shows (at 0:08) a slow motion of the same phenomenon.
Does someone has an explanation for this ?

 

[timetraveller]

Paul, I cannot tell from the video where the spark is. If it is across the points then that would indicate the capacitor is failing. If it is somewhere else can you explain where it is in relation to the points for example. Looking at the video it is possible that there are two positions and types of spark.

 

[Paul Coene]

Post deleted - see #15

 

[timetraveller]

OK Paul, the question is where does the spark go from and to?

 

[Paul Coene]

I have no idea. That's exactly why I posted this thread.

 

[timetraveller]

Are there no signs of burning or pitting on any of the surfaces? It looks to be along spark and so it is probably on the high tension side of things. The points break the low tension side of things so, just guessing here, I think it must be a leak on the output side of the windings but I can't see where it starts and where it ends. We need Magneto Man to give us the benefit of his expertise on this.

 

[erik]

I had made no good experiences with the screw on capacitors and returned to the oroginal location with two capacitors recommended by magnetoman!With the brightspark capacitors I had firing points all the time.Best to see in darkness!Erik

 

[timetraveller]

I helped one of the local members to fit a Brightspark to a Comet and it worked OK for years. It did break down after seveal years but he was able to replace it by the roadside. I have no connection with Brighspark.

 

[Paul Coene]

I guess it wouldn't be bad to provide some extra explanation. Here we go:

4000 mls ago, one of the pick-ups came loose during a ride and next, the condensor was broken. I replaced it by a Brightspark - without disconnecting the original one- (I thought: why not give it a try ?) and it worked. I had no problems at all since then. With the magneto that is. Only recently, during the inspection of the ignition timing, I was faced with the problem described in post #1. Next, I sent the magneto to the belgian dealer of Brightspark for repair as he has the required equipment and experience with magnetos, wanted to return it within a couple of days and of whom I thought he was going to remagnetise the magneto after reassembly. Well, he didn't, and on top of that, having no experience with KVF magnetos for Vincent engines, he mounted the end cap wrong. It took quite a while before I found out ! As I was not aware that the end cap could be mounted 180° wrong, I tried everything that came up in my mind to find the culprit. I even managed to start the engine and put the whole neighborhood to flight...
The reason I'm telling this, is because there's maybe a causation.

 

[greg brillus]

It looks like the brightspark condenser to me.........probalaby where the thing attaches to the pionts base plate........I have a couple here in a packet, but never used them.......My understanding was the original condenser was supposed to be disconnnected first.........Primary voltage gets up to around 200 volts when spinning, so a leakage could cause the issue........perhaps the attachment screws are not quite tight enough.