Yup, 5 turns of decent thread should be enough normally. The taper does the real work, the thread and nut just make sure it stays stuck on! There are remedies in 'worst case' but you're not there. You might have quite a deep nut on there I'm thinking.shaunstaples wrote: ↑Mon Feb 20, 2023 10:45 am I thought the thread was a bit short only because there is about 3/4 of the nut doing anything, and had spotted the undercut on brass ring.
Hadn't thought about cone on slipring, was going to unsolder the one I thought it was and check resistance.
Everything looks good and has cleaned up lovely. The end float feels right, it's not tight and there's no detectable play when screwed up.
Will the soldered wire to earth in pic be return side of condenser and winding connection buried in resin?
Not quite following your 'cone on the slipring' sentence - but the nose where the HT coil wire enters is part of it, and the whole plastic ring comes off the shaft when the bearing race and oil flinger outboard are removed. But if it's not damaged at all, and you are getting 4.8K ohms from the brass track of the ring to armature spindle, I wouldn't touch it. More risk in removing than in leaving in place.
The steel cone or taper and thread on the brass drive end doesn't detach - or very definitely shouldn't! When they work loose or become detached, that's serious work to fix - and sometimes can't be. Very horrible job to maintain alignment etc etc.
Can't see from the pic which side of the armature we're looking at - but the LIVE wire has two strands under the insulating sheath, the earth lead just one. The live wire is on the opposite 'side' and the other end, from the nose on the slipring as I said. The procedure for identifying, and pix of a typical 'snip' are here:
http://www.brightsparkmagnetos.com/cond ... k_snip.htm
When you've sussed out which wire is which, leave the earth side untouched, exactly as it is. That earths the HT and LT windings as well as the old condenser. But, with the live side of the condenser snipped, it's now out of circuit so that's why you can leave the earth alone. It will now just earth the windings to the armature, and the earth brush is what (primarily) makes the circuit back to the magneto body and the rest of the bike.
With a steel pinion like on our Twingles, the armature shaft is actually earthed anyway - badly and oilily - through the drive train - but not so on bikes with fibre drive pinions, like many Beesas and Trihards. You may also have a brush on the rear face of the contact breaker backplate - that's an auxiliary earth. Some do, some don't. Older machines with other sorts of magnetos had ONLY that earth, and Lucas continued to make contact breakers with the facility for a long time.
When you get your EasyCap, just remove the fixed cb point, withdraw the 'top-hat' insulator tube that engages with the brass block's underside and remove the insulating plate between it and the backplate - put the circuit board on instead with the top-hat jobbie shoved back through the board into its hole and screw the fixed point block back on. Job done.. The rear side of the circuit board is earthed, the upper side is live, along with the fixed point and the centre screw. The capacitor soldered on the board makes a bridge between the two sides via two tiny tinned holes on the outer end of the arm which you won't easily see (but can maybe from the rear side).
So you end up with:
low tension winding
cb points; and
condenser
all in parallel, which is what it's all about.
A bit of trigonometry would help on the actual BTDC depth needed with the dial gauge at an angle, if you could be bothered and knew what the plug'ole angle of entry was (60°ish?). I usually just use a rod held as vertically as possible, or, if feeling virtuous, a timing disc - but not easy to attach unless the primary side is off - and we don't want to go there too often with tin chaincases, even with new Club seals!
A degree or so either way won't make any serious difference anyway, and there are views as to what's 'best' these days with modern fuels, which contradict sometimes the book settings. More important, if you can, is to see that the points open on both sides when the pistons are at the same distance before TDC. It is tempting to check on the cylinder that fires when the points are in a place you can see easily . . . but you'd be surprised how often there is a noticeable difference if you check both. In moderate cases you can split the difference setting the timing, but in severe ones, other fettling is needed. 1°error on the mag = 2°on the crank . . .