95t'bird Ignition Problem

[Berowrat52]

My 95 Thunderbird has developed a problem that I have never encountered before.
The bike refuses to fire up so I removed and cleaned each plug in turn and tested them for spark.
When the starter is cranking there does not appear to be any spark but as I release the starter button I can see the plugs fire momentarily.
Has anyone experienced this problem before or can you shed some light as to what may be the problem? Cheers

 

[Greyfell]

I'm a newbie, so I am not much help. I just can't believe this talkative bunch hasn't responded to you, unless they did it by PM.