Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: Rolfbulmer on April 29, 2022, 12:39:15 PM
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Hi guys,
A question please:
I require a set of ignition coils, do I go for second hand oem for about £50 or do I go for new replacement equivalent ranging from £50 to £80.
Any help, advice appreciated thanks.
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Repair yours using the tutorial from Ash in alladins cave, cheaper than both
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Second that, I did mine for first time for the 750. Not a difficult job once you have the stuff.
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I am at t he same point with the sme question.
I priced up the reccomendede resin and the Milliput epoxy which came to, as cheap as i could price it, £54...............The new coils start at about £55 so I can understand why youre considering new ones.
I'm still not sure but it appears that I do have som HT lead in stock :) ;D
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I am at t he same point with the sme question.
I priced up the reccomendede resin and the Milliput epoxy which came to, as cheap as i could price it, £54...............The new coils start at about £55 so I can understand why youre considering new ones.
I'm still not sure but it appears that I do have som HT lead in stock :) ;D
Send me your address and I will post you enough epoxy to do a set of coils. The Milliput Putty will do about 3 sets of coils!
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Are you sure Ash, thast bloody good of yiou mate?
MIne are shagged with one of the leads broken off the front of the coils and hanging limp. I would like to do them but it was all about the cost and time equation for me as Ive just lost my job and having to reign things in a bit currently. Let me have youre address in a pm Ash and I'll bung you some recompence for your kind gesture. Really appreciate this Ash, thankyou mate :) :)
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Do the coils really need repair? I have had quite a few coils in my hands that by feel seemed to have flimsy plugwires, but in fact were OK.
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Yeah, its actually snapped inside and hanging by a thread.
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I am at the same point too. My coils ht leads look like they have been ripped out and thrown away - not with bike when I got it.
Cost of resin plus HT leads and plugs brings it to the point where new may be cheaper.
Just not sure what to do.......
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New may be cheaper but unless they are new genuine then they ain’t cheaper in the long run imo.
The original coils are extremely robust, the weak point are the leads, they are now 40-50 years old and subject to frankly a bloody hard life, hot/cold environment, water being blown onto them at high speed etc, it’s really a wonder they lasted this long.
From personal experience I find that fitting the coils backwards, so that the leads come out of the back helps a lot. Even in the 70/80s they were known for shorting out onto the engine, in the dark and damp it could look like some sort of laser show going on under the tank. I distinctly remember wrapping the leads in insulation tape back then. I felt the reason was that the routing of the leads caused them to be filled with water, as the coil exit faced forward water would get driven in there by the speed of the bike, collect in that area and the slowly creep down the lead under gravity. Turning the coils around stopped this, the leads now had to route across the engine and the heat helped dry them. I could run with bare leads again, even hold them and not get a shock. In short it stopped all the problems with shorting, the leads looked better routed across the top of the engine rather than having big loops exposed under the headstock. It also meant the ht caps were better protected as the coil leads were no longer facing forward and again open to water ingress but backwards and thus the wind now helped dry them instead of forcing water into the cap.
Just my experience, others have since done this and I’ve yet to hear anyone say it didn’t work better. ,
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http://www.sohc.co.uk/index.php/topic,14939.msg122821.html#msg122821
This is how I fixed my coils, been working perfectly ever since.
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Excellent advice given here. In the meanwhile practice prudence when pulling the plugcaps. Always concentrate well to avoid too much movement resulting in hurted connections.
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Are you sure Ash, thast bloody good of yiou mate?
MIne are shagged with one of the leads broken off the front of the coils and hanging limp. I would like to do them but it was all about the cost and time equation for me as Ive just lost my job and having to reign things in a bit currently. Let me have youre address in a pm Ash and I'll bung you some recompence for your kind gesture. Really appreciate this Ash, thankyou mate :) :)
Don't need any payment chap.
I chose to use the liquid epoxy from RS because they quoted guaranteed electrical properties ... the epoxy putty manufacturer couldn't provide any such data. Plus the liquid epoxy flows in-between the HT cable outer cable and the body (which is not epoxy BTW it's injection moulded thermoplastic). I always abrade the outside on the HT cable and run a Demel with a ball ended tool on the end down the slot left in the coil body in order to remove anything which will prevent a bond (i.e. dirt or plasticisers etc left from the old cable).
When I have a chance I will do some testing on the epoxy putty to see if it's dielectric properties are good enough .. i.e just use the putty for the whole job.
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Still not done mine yet Ash, I intend to fill then hole to just under the coil body then fill to just above with Araldite and then sand smooth and spray the coil after with satin black paint after also replacing the wires to the points. Might as well do a decent job whilst I'm doing them. I have 3-4 sets of coils to do. I'll do mine, do a set for the BIL and sell the others. Mine will have red leads to match the NGK caps, might also do a spare set with black leads in case I don't like the look.
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Still not done mine yet Ash, I intend to fill then hole to just under the coil body then fill to just above with Araldite and then sand smooth and spray the coil after with satin black paint after also replacing the wires to the points. Might as well do a decent job whilst I'm doing them. I have 3-4 sets of coils to do. I'll do mine, do a set for the BIL and sell the others. Mine will have red leads to match the NGK caps, might also do a spare set with black leads in case I don't like the look.
On the last set I did for Trigger (last week) , the HT coil snaked quite a bit in the injection moulded case. That would have been really difficult to pull the wire out and even more difficult to push back in again.I prefer my original method of re-encapsuation and guaranteeing getting a total bond all the way down the HT cable. After all, the fact that the HT cable pulls out of the originals shows that there was never proper sealing of the HT cable to plastic body. But horses for courses I suppose and both methods are much better than buying really low primary resistance aftermarket coils IMHO.
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The 500/550 coils though don't snake at all, straight in and straight out. So the smaller hole way of doing them works just great IMO, I have fitted one set of leads in the coil body, I used a 1m length of HT lead and didn't cut it, so it's a large loop at the moment, I put silicon sealant on the end as it slid in so it sealed after fitting. I also intend to slide the outer lead cover right up to both the cap and the coil so in essence the lead is not exposed to the weather at all. The reasoning behind the loop was to ensure I could cut the lead where I wanted so there was no chance of it being too short, as my coils face backward and route across the top of the engine I find having them slightly longer than standard helps to route them completely out of the way.
We'll see if the idea pans out I suppose.
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The 500/550 coils though don't snake at all, straight in and straight out. So the smaller hole way of doing them works just great IMO, I have fitted one set of leads in the coil body, I used a 1m length of HT lead and didn't cut it, so it's a large loop at the moment, I put silicon sealant on the end as it slid in so it sealed after fitting. I also intend to slide the outer lead cover right up to both the cap and the coil so in essence the lead is not exposed to the weather at all. The reasoning behind the loop was to ensure I could cut the lead where I wanted so there was no chance of it being too short, as my coils face backward and route across the top of the engine I find having them slightly longer than standard helps to route them completely out of the way.
We'll see if the idea pans out I suppose.
You won't get a strong enough bond with silicone IMHO but just my tuppence worth.
I have done all of mine anyway now including the ones for my Honda twins and S90 single. So never likely to do any more ;)
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The hole is still empty though Ash, so if I filled it mostly will that stuff you sent me wouldn't that not only seal the lead into the body but hold it there as well when it sets?
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The hole is still empty though Ash, so if I filled it mostly will that stuff you sent me wouldn't that not only seal the lead into the body but hold it there as well when it sets?
As I have always said Ken .. each to their own. I have done loads of coils for people on here using my original method but concentrating on getting all of my bikes built up now so not doing any more, as I don't really have the time.
Incidentally, only ever found one coil to be unsuitable for re-furbing . It had a really low secondary resistance ... something like 9k Ohms instead of typically around 14k for a 'good' one. My only explanation was that it had possibly been used on a CDi system and run without a plug connected or when it was open circuit due to HT lead fracture .. in which case the higher than normal HT voltage generated by the Cdi may have flashed over between the winding wire coils ...just a theory though ..could be b*llocks. ;D
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I can vouch for ash and his refurb method. In recognition of my complete incompetence he was kind enough to refurb my coils…they are as goos as new and function flawlessly. Based on my own experience I’d recommend his method every time.
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Im doing it and already on with faffing in the shed! 8)
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Ok, I am going to try the repair option.
Any tips please on how to replace the LT leads also.
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LT leads? Are you saying the wiring loom is beyond repair?
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No I think he's referring to the leads from the coils TO the loom. Not done mine yet but it looks like they'll just unsolder from the coils.
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No I think he's referring to the leads from the coils TO the loom. Not done mine yet but it looks like they'll just unsolder from the coils.
Yes, they do. Where they connect the coils, you may find some isolating black goo, but you can scrape it off.
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No I think he's referring to the leads from the coils TO the loom. Not done mine yet but it looks like they'll just unsolder from the coils.
Got it. I’d considered that, but was lucky they were sound.
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Yes, I was referring to the leads coming off the coils. Thanks for the tips.