Yep,flywheel has to be 'on' of course or there's no cam operating. Hold it on advance & set gap at about 14 thou max fully open which will be about near the end of the access slot. You 'could do it without holding it on advance but not sure you'll get it far around to be fully open & adjustable as think the slot might be too far around. Points gap determines timing although your timing is variable with revs & when above idle or up a little bit more the timing will be in the ball park of 1.8mm or 72 thou before top. For starting, timing will be close to tdc just for kicking.

Here's another idea just to confuse, 'but hope not'!!
There will be a timing notch in the flywheel slot that aligns with a bent tap pointer coming of the lighting coil. So while held on advance you could loosen the points screw with the the notch aligned, "or loosen points then align notch", doesn't matter. Then set the points 'just' touching & tighten the screw. That way the timing will be right & the points gap will be within spec of 12--15 thou. There's a few variables like how worn the point lifting heal is & if the advance mechanism is worn in where the arm engages--but it'll be close.

& one more--those damn points always move or alter a whisker as you tighten the screw so keep that in mind. Eyeballing is pretty good for determining when the start moving unless you have an analogue meter on the black wire from the mag to watch closely for slight needle variation at the moment of opening.

Hi thanks again
have had a squint at the service manual which speaks of dial indicators and points checker, haven't got those..

i can find TDC either by whipping off the head or some other heath method and then mark the flywheel accordingly i guess
got it the adv/rtd mech needs to be open and can achieve this with a small screw or probe to keep it open
so far so good..?
looking as closely as i can doesn't show even slightest movement on points and i wonder if the lifting heel is worn and new points are required
last question, would worn points heel be causing the misfire when it was running?
thanks again
D

I have spark!
Seems like a dead short on what looks like a blue (or faded green wire perhaps) going to engine casing (above sprocket) terminated in a crimp onto a screw if anyone knows what that fidget does?
Can’t tell yet if my timing adjustments are right but it fired up
Had to kill it straight away as no pipe on it as am blowing that one through while it’s off
D

Might well be the wire for the neutral light switch. Originally sky blue, but age, dirt, heat etc causes discolouration.

Yes that would make sense
Would a short in that as In broken cable cause no spark though?

Kind of confusing... you've been talking about runaway revs and misfire... now have jumped to "I have spark"?

The neutral switch wire has nothing to do with spark. It will be grounded with the trans in neutral.

Figure out how to block open the advance, adjust the points... it's just a single screw... and get the points to just crack open when the piston is 1.8 mm BTDC and you'll be fine.

Well it was a misfire under load and runaway revs which I eventually took to being potentially two separate issues
Hopefully sorted the air leak with new gaskets
THe misfire I was trying to get to the bottom of and during the process it stopped sparking
New to the whole dark art of points which is probably evident but I feel like I kind of get the gist of the process
I will know more tomorrow when I get the pipe back on whether it’s timed right and the air leak is sorted and will update

Back together and riding like a new bike & better than it ever has tbh
Much quieter, revs stable no misfire, even power band & perfect idle

During the course of the adventure I found the broken wire to neutral
A bad wire between coils, soldered it heat shrink and shield
My point setting seems to be on the spot
New top & bottom gaskets
A huge thanks to everyone who took time to help with this
A donation for the manual dl will be forthcoming soon
All the best
D

Congratulations!!! Nice job!