Anyway, if it has a mag the bike's electrical system voltage (whether 6 or 12) is irrelevant wrt the ignition as the the mag is a totally self-contained sparks generator.
I think the bike is new to you and many things may well need tweaking or sorting (e.g. the mag's unsuitable without an A/R facility for starting, which why you're having trouble). Giving the c/b points and the mag slip ring a clean and fitting a new plug (Champion N5C or NGK B7ES (or B8ES) may improve the spark.
Check that the HT lead is of the solid copper core type and the plug cap doesn't have an integral suppressor.
Excuse me for nagging but on searching your threads to find the year I notice you posted this.......
As several owners will vouch, incorrect assembly of the rear wheel parts and speedo drive can result in the rear wheel rapidly locking up solid and possibly a nasty prang. You must get it right.Stevecampy wrote: ↑Thu Oct 07, 2021 7:20 pm
Speedo cable needed . Anyway I have put back wheel together to the best I can need a pdf exploded Brie to help if all bits are there . Got a Speedo cable that turns and also a rear wheel that turns .
Here's a cutaway of the assembly
https://www.jampot.com/pic_display.asp?id=820