Thackero. So it ran, then nothing? Something could have slipped or settled. My feeling is the magneto is the place to look. Even with faith in the reconditioned unit, a quick look at the simple stuff is well worth a go. Try it first without the points cover cap. An unintended earth grounds the magneto, no sparks at all.
I'd check the earth brush by the nameplate is all good, likewise the pick up brushes nice and free, running on a clean slip ring. If a steel points backplate make sure it has been set up for clockwise rotation at the points end, and that the spring blade does not touch the cam ring. Early type Brass breaker points come as clockwise or anti-clock variants. In all cases the pivot point leads the fibre heel as the armature turns. So, are they the right points, clean, gapped and electrically and physically sound and correctly located and tightened down onto the armature taper?
Centre points bolt also has to be the correct one for the points used, they are different lengths, brass type also has a taper under the head. Points have a fine key location to the armature, make sure this is in order and when fitted and tightened in place the points plate rotates without wobble.
Always set the points gap before setting the timing. Correctly fitting the plug leads is easy, a cylinder coming up on compression, points just opening, brass segment on the slip ring is visible "down the hole". This plug lead goes to the cylinder on compression.
A good strong spark in the right time and place, a swig of Start You B**ta*d and you should get some sign of life. If not, there is something mechanical slightly awry. Magneto drive gear goes on the magneto armature positioned with points just breaking. Manual magneto set to full advance, if an ATD unit, wedged open, also to give static timing at full advance. Crank position set as specified, timing gears loaded backwards to eliminate backlash and simulate driven condition. Usual problem here is the drive and armature move as the retaining bolt is tightened, so first settle the gear on the clean, dry taper with a gentle tap, not a big smack which can be expensive.
This link may help if you have to dig even deeper.
https://www.a7a10.net/forum/index.php?topic=5549.msg37740#msg37740 Thanks expressed to Musky for the additional link to useful stuff.
Swarfy.
Additional. Reading back through the original posts this engine has run just once. Aim for regular firing on start spray before worrying too much about the carb. Even the best carb is useless without mechanical and ignition systems set correctly and in working order.