Slight modification to ASH's Ignition coil fix

[Bryanj]

Secondary resistance is from one ht lead to the other on a rwin lead coil as fitted to the fours

[Erny]

aaaa to the other HT lead? The only option I did not think about!!! 

[paul G]

Yes, I know, it is decribed at the beginning if this thread

BTW
When i tried to measure resistance of secondary coil, I was unable to measure - not even sure if method was OK - I suppose one end of coil is end of HT lead and another is one of primary wires, correct?
I tried all, I mean end of HT lead ( I tried with and without cap and plug) and other to black or yellow (had coil 2-3 for test). Each time infinite resistance... but coil works, not sure if perfect but works...
What I did wrong?

  didn't read back that far !

[AshimotoK0]

Here is the 7mm HT Lead that Trigger, Julie & myself have used.

https://www.sparkplugs.co.uk/beru-ignition-cable-7mm-pvc

[AshimotoK0]

I found some nice sleeping bits its black silicone rubber and although supposed to be black it's more if a really dark grey.

[the-chauffeur]

If you don't much fancy chopping the wires out of the coils, I've found that the same mix of isopropyl alcohol to wintergreen (ratio 3:1) that folks on YouTube recommend to put life back into hardened rubber parts will rejuvinate the HT leads surprisingly well. 

I'm in the middle of a CA77 rebuild and as you can imagine, the 50+ year old coil leads were very, very inflexible.  I took a length of 22mm pipe, plugged one end, filled it with the alcohol/'green mix, coaxed the brittle leads into the open end and left it standing for about a week.  The great thing about that method is that it takes up no space - and it uses very little juice.  During that time, the mix penetrated the cable outers and put a fair amount of flex back into them - and something about that mix keeps the rubber supple long after treatment.  I'm confident I'll be able to easily reroute the leads when the bike starts going back together in a few weeks' time.  I've also got a much shorter length lead from an XL350 sitting in a jamjar of the stuff while that gets torn down.

Admittedly it's not an option for everyone; the leads will never return to the way they were when they were new, and it's no substitute when the outers have frayed or cracked.  But I thought I'd mention it as a non-invasive option that might help those who, like me, find chopping into coils a little bit daunting.

[AshimotoK0]

Most of the coils I fix have broken / fatigued or  inner conductor wires ... so personally I would always opt for HT lead replacement. Also not so sure about the electrical conductivity of wintergreer stuff as I always use Refos 50 for softening rubbe/polymers.

[AshimotoK0]

https://www.ebay.co.uk/itm/SP75-Silicone-Rubber-Tubing-7-5mm-ID-x-1-0mm-Wall-Black/264420895150?hash=item3d90b6a9ae:m:mYQcKjf4DaSMrplJMeNyaaw


Closest I can find size wise to outher HT sleeving  but it's silicone rubber not nitrile.

[philward]

I've done 2 sets Ken - second set was much better due to practice. Make sure you have a decent output soldering iron as the HT lead core wire you are soldering takes the heat away from the solder point. Ref your question, I would not go too close to entry pont of the lead to solder as you want some adhesion between the lead and the miliput to stop the lead twisting when all done - the longer the depth of the grind back, the more adhesion.
I used a rotory burr in a drill to grind back and that method was quite controllable in grinding down to the wire. Also, make sure the 'mould' you make to hold the dialectic epoxy is realy secure as it can run out easily.
Don't know how Ash feels about that.

[philward]

Not knowledgable on epoxy Ken. I used a Sealey SD100 Soldering Iron 100W which was great (bought this after struggling with smaller iron on the first set of coils).
I had slightly lower HT lead to HT lead figures which Ash said was fine - I messaged Ash and he was good enough to help me with all the values. Ash is your man for the technical stuff!

[philward]

Can't remember but if you start grinding back from the lead entry point, you will be able to stop before the terminal. In my experience (only 2 sets), when you grind down to the leads, grind only half way into the insulation so that you still have a 'tunnel' to feed the new lead into (just enough for the lead to flick out and the new lead to flick back in - that way, the new lead is held in with a little bit of friction that holds the tinned copper leads to the old tinned copper lead, allowing you consentrate on the soldering (without new lead moving away from static old lead) - if that makes any sense.

[philward]

This the soldering iron I used (Ash suggested it) https://www.ebay.co.uk/itm/Sealey-SD100-Soldering-Iron-100W/121093453336?epid=1042172152&hash=item1c31bb7618:g:cu0AAOSwezRb6~T-

[AshimotoK0]

There is a brass terinal near the end of the bulge. However, if you decide to desolder the wire from it and resolder the terminal  then do so with great caution. The plastic used is thermoplastic .. i.e. it melts when hot and if you are not careful  the terminal flops around if the plastic around it melts and can break the ultra fine secondary wire soldered to it. If this happens the coil is essentially scrap.

[philward]

I suppose you get what you pay for! Does work ok though and have 2 other lower power guns for the smaller connector work