ST70 6 volt spark problem

Hi All

I hope someone can help.
I have a 6volt ST70 “L” reg.
When I bought it it obviously had this fault.
The spark seems weak, but if a new spark plug is fitted it starts and runs.....once, occasionally twice.
Fitted new points, condenser, coilcoil all genuine Honda parts.
Got an aftermarket generator from Shire bikes but mine is different. Mine is slightly smaller dia and has a 6 pin plug instead of four.
I am a car mechanic, my mate is a car mechanic. But this thing has us both baffled.
Is there anywhere I can get a generator with a six pin plug? We are convinced that this is the problem......unless you know different.

Any thoughts will be gratefully received.

Suggest check the earth connection of the coil.

On my ST the weak spark was attributable to coil not earthing well enough onto frame. All the components tested good, so I created a separate earth from coil bolted to frame and ran it up to another earth bolt under seat. The coil is supposed to earth by just being bolted in place but paint or powder coat can isolate it.

Good luck

S