sorry about the bad link, the data sheet for the transformer is at http://www.bourns.com/pdfs/pm61300_series.pdf and the digikey number is M8101-ND. these are about $4 each and what i like about them is that they seem ready to use with the primary, secondary and feedback windings in what looks to be the proper ratios. not having to wind a transformer will make this ignition so much easier.

in the attached image (sorry about the poor quality) you can see the type of spark coils i was talking about. the cut away coil on the left is from an echo CDI, the bottom layer of the coil is the primary winding with about 27 turns and the four upper layers are the secondary. the ferrite core is 6mm diameter by 13mm long. on th right are parts from an old 3W coil. the ferrite core is 6mm x 15mm with 30 turns of 0.4mm wire in one layer as the primary. this fits into a pair of finned bobbins (only one is shown) where there are 6 layers of windings for the secondary, each about 500 turns of 0.1mm wire.

the coils i made were copies of the 3W style but on homebrew bobbins. i wound them on a slow, variable speed drill with a revolution counter cobbled onto the shaft....took a couple of tries to figure out how much tension to put on the wire so as not to break it. never really searched but there has got to be some kind of transformer or inductor out there that might work for this kind of secondary.....if all we had to do was wind the 30 turn primary these ignitions wouldn't be so scary looking as a DIY project.




dave