Honda-SOHC
Other Stuff => Misc / Open => Topic started by: SteveW on January 19, 2018, 08:16:58 PM
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Started to follow ASH's excellent ignition coil fix instructions, but wondered if the same result could be achieved with only cutting a small amount of the casing away.
I cut a small access hole as in the picture with a Dremel with one of those metal burr attachments. Cut through the old HT lead and yanked it out easily.
Ran a 7mm drill bit through the hole vacated by the HT lead, just to clean it out, virtually no material was removed.
Tinned the remains of the old HT lead. Stripped the end of the new HT lead and tinned.
Slid new HT lead up the hole to meet the old one, soldered together and dropped epoxy into the hole.
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Wow what a good job I won't be throwing old coils out any more
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That is very cool indeed...
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Will it suffer from water ingress though due to water running along the HT lead?
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Will it suffer from water ingress though due to water running along the HT lead?
Cool ..you could coat the wire in liquid epoxy then push in to fully seal. I would recommend the liquid epoxy i used in the writeup though .. very runny with heat and good dielectric strength.
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Will it suffer from water ingress though due to water running along the HT lead?
The old HT lead wasn't secure in the coil housing, it was literally held by the end of the cable. Once the cable was cut it easily pulled out.
The new cable is 7mm and its a perfect fit in the hole. I suppose water could possibly get in but a tiny bit of silicone sealant would stop it.
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Interesting I thought they were sealed.
You would think the damp would get too them.
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Interesting I thought they were sealed.
You would think the damp would get too them.
Some of them , particularly the Honda twins, ones have epoxy smeared around the exit of the HT cable. Best to try to wipe any plasticiser etc off the inserted bit and slightly abrade to get a bond.
BTW if you tried that method with the Honda twins ones you would need to identify the wooden (yes wood!) dowel that anchors the cable and drill it out, then it would work OK. The twins are not soldered they just push into a pin inside the coil but can be soldered on repair.
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When I eventually do mine I will seal them up as I don't shy away from the rain and it drives me crackers when they start coughing & farting.
Saying that the mega cheap coils I bought on eBay are holding up well I noticed there completely sealed with some sort of epoxy.
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When I eventually do mine I will seal them up as I don't shy away from the rain and it drives me crackers when they start coughing & farting.
Saying that the mega cheap coils I bought on eBay are holding up well I noticed there completely sealed with some sort of epoxy.
If you get mega cheap ones make sure primary is around 4 to 5 Ohms minimum otherwise on standard points, the points won't last too long.
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I never checked the Ohms but they have been in there for some time now.
The used points that were in the bike when I bought it about 5 years ago still haven't needed to be touched.
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One thing to watch with modified method is that in some coils I have don, on Honda 4's, (e.g.a pair Trigger had done), the HT cable 'snakes' within the potting. I will give it a whirl sometimes though and give it as an option in the write-up...obviously accredited to you Steve :)
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I have lost track of the amount of coils the ht lead has come loose in they seen to be able to twist inside the hole easily if the mod is done it is worth glueing the cable so it don't twist
I had my engine running in my test bench using a set of coils whete I could pull the lead out of the actual cool housing it still ran ok though
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My original 45+ year old CB750 HT leads had gone rock hard, and I was getting all kinds of poppage and bangage that nothing would fix. Thinking they were sealed for life and unreplaceable I bit the bullet and bought a new set of OEM coils with leads from Mr Silver, at over £200 I have bought good, running bikes for less.
It cured all the missing and plug fouling, but I wish I'd seen these fixes first! :-[
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Just replaced the other lead on this coil (the shorter lump).
Just a note that this cable seems to be set into the potting a bit deeper than the other so the hole will have to be made slightly deeper.
Again, just like the first cable, once I had cut through the cable it pulled out easily.
Got the cable and new plug caps from these guys, cable was about £1 and plug caps about £2.50, delivered in a couple of days.
http://www.gsparkplug.com
GPLPVCB-GS - 7mm HT Ignition Lead Cable - Wire Core PVC Black
XD05F-B-GS - 1x NGK Resistor Spark Plug Cap XD05F black (8072)
VD05F-B-GS - 1x NGK Resistor Spark Plug Cap VD05F black (8052)
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The HT leads on my 1969 CL450 are rock hard, and the rubber seals around the plug caps fell apart when I touched them.
Rest assured that having read this thread, before I even think about looking for a new coil pack I will be cutting into the old one with a view to replacing just the leads, once bitten twice shy and all that.
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Re-opening this topic.
Found I better replace HT leads on my stock coils, using above mentioned method ;)
Can somebody recommend proven supplier of HT leads? (please recomment exact type i should look for)
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I have used these quite a few times.
https://www.gsparkplug.com/ignition/ignition-lead?p=4
Mine have been the 7mm ones ensure you get the copper core type not the Graphite type.
Regards,
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I have used these quite a few times.
https://www.gsparkplug.com/ignition/ignition-lead?p=4
Mine have been the 7mm ones ensure you get the copper core type not the Graphite type.
Regards,
Can't remember the 7mm stuff I used originally but Trigger and Julie bought some last year, so they will definitely know. Needs to be tinned copper multistrand conductor ideally.
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There is also a slight modification on here somewhere which shows you that you do not have to grind/file down the whole of the raised section where the HT lead is encapsulated.
I did it by coming in around 20mm and then grind/file down about 15/20mm section and you can then cut the HT lead pull the old one out and slide the new one in and solder together.
When cutting the old one don't forget to leave enough to solder back onto ;). Makes it easier to waterproof and recreate the domed section.
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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?
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Secondary resistance is from one ht lead to the other on a rwin lead coil as fitted to the fours
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aaaa to the other HT lead? The only option I did not think about!!! ::)
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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?
;D didn't read back that far !
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Here is the 7mm HT Lead that Trigger, Julie & myself have used.
https://www.sparkplugs.co.uk/beru-ignition-cable-7mm-pvc
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I found some nice sleeping bits its black silicone rubber and although supposed to be black it's more if a really dark grey.
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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.
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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.
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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.
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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.
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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!
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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.
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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-
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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.
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I suppose you get what you pay for! Does work ok though and have 2 other lower power guns for the smaller connector work