1989 Honda VTR 250 Weak spark at the plugs

I am trying to get a 1989 Honda VTR 250 back on the road. When I first checked it for spark at the plugs all I got was a weak yellow spark from the front spark plug and nothing from the rear. I have tested the coils and pulse generators as stated in the Honda factory manual. Fixed a few nicked wires from the coils to the CDI. With just the motorcycle battery (fully charged) I get the same results, weak spark on the front cylinder and no spark at the rear. If I hook up a fully charged car battery ( i have a spare in my garage) I get a weak spark at both spark plugs. Before I start replacing parts with other used parts as CDI's and pulse generators are no longer available new, Does anyone have any thoughts about what could be wrong? I did get new spark plugs. What would cause consistent weak spark(yellow) at the plugs? Thanks for any help. John