Honda-SOHC
SOHC.co.uk Forums => Other Bikes => Topic started by: alfiembra on June 23, 2022, 07:18:42 PM
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Looking for a local sparky to help me with an old 6 volt Honda C50 step through which has no spark.
I’ve replaced everything electrical on it points, condenser, coil HT lead cap and plug and cannot get a spark. Other than checking continuity that’s as far as my troubleshooting skills go, so really need help from anyone that can come and have a look at it. It was running briefly about a year ago but since then It will not spark. Any help will be gratefully received with all the tea and biscuits you can handle.
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No help directly as t'other end of country from you. Although biscuits very tempting ;D
But one easy thing to check that often catches out on points;- the little bolt on the points that captures the wires on a terminal MUST under all conditions not touch the earth (the bracket it's bolted to) EVER, apologies for shouting :) but all of the little insulation washers etc must be in place to prevent this happening.
There's usually a few of them, something sleeving the bolt as it passes through the bracket too. Any tracking to earth here and nothing will happen with the ignition in the way of switching the coil. The only route to earth is via the points contact to the other post (the static one) so worth checking through carefully to see if there's any physical possibility.
The way to check it electrically is to set a meter to beep on continuity, put one lead onto earth, the other to the wire going to the points and with the points closed it should beep, with them opened it should stop beeping indicating that the points are switching the circuit open.
Worth a look through or put a photo on of the points plate for others to see and help with suggestions.
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Does the C50 have a battery if not is there 6 volts at the coil when ignition is on and kick start operated?
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I believe it does have a battery. I used to own a C90, which is similar
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Have you checked if you have a good earth connection to the frame?
Sent from my moto g(50) using Tapatalk
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C50 doesnt use battery to start, c90 does.
Most common reason for c50 to not spark are
Points gap wrong
Wiring earthing
Kill/ignition switch fault.
The ignition switch gronds the points wire to stop the spark so disconnect and try again
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Thanks everyone for your replies great suggestions there for me to check. I’ll be trying again over the next few days and will report back.
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Sorry for the long delay in replying to the suggestions to get my C50 to spark. Long story short tried everything suggested to no avail and haven’t been able to get a professional opinion on what the problem is. However I did have a theory put to me that maybe the flywheel has lost its mojo and the magnets are not creating enough magnetism to generate a spark. Don’t have a spare and probably looking at over £100 for a replacement. Any opinions? I certainly think it’s plausible as I’ve changed everything else to no avail.
Also I’ve seen YouTube videos on how to resurrect weak magnets using neodymium magnets. Anybody tried that?
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Sorry for the long delay in replying to the suggestions to get my C50 to spark. Long story short tried everything suggested to no avail and haven’t been able to get a professional opinion on what the problem is. However I did have a theory put to me that maybe the flywheel has lost its mojo and the magnets are not creating enough magnetism to generate a spark. Don’t have a spare and probably looking at over £100 for a replacement. Any opinions? I certainly think it’s plausible as I’ve changed everything else to no avail.
Also I’ve seen YouTube videos on how to resurrect weak magnets using neodymium magnets. Anybody tried that?
Not saying loss of magnetism is not the cause but more likely a connection on the windings I would have thought.
Is the flywheel showing signs of magnetism in terms of attraction to Ferous steel?
Someone on this forum should have detailed knowledge I would have thought.
Does this link help in terms of tests.
.https://www.youtube.com/watch?v=uggJMnuexMc
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Thanks for posting that link, very interesting.
I have checked for continuity, which it’s got, but I haven’t checked to see if the numbers are out with specification, off to do that now. ;)
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Ok did a quick check, there are 3 wires coming off the primary coil a pink, a green and a yellow.
According to the Haynes manual I have, the resistance (apologies if I’m using the wrong terminology) across the coil should be between 0.2 and 0.6 ohms. Mine is right on the top end at 0.6 ohms this is measured on the pink and green wires which are soldered to each end of the coil. Also get the same reading at the connector ends where they join the main wiring loom. The third wire (yellow) comes straight off the coil windings, and according to the Haynes manual there should be continuity between it and the green wire, I’m mostly getting an open circuit reading with that but occasionally a flicker of it trying to make a circuit. I need to find a better wiring diagram for the bike as the Haynes one doesn’t have a specific diagram for my model. However it does seem to suggest an issue with this coil.
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I'm not skilled to advise but many decades ago I put a set of magneto coils in our airing cupboard for several days to dry them fully out. I was told that old coils due to age can absorb moisture over decades then sometimes dry out & work again. It worked for me that one time.
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Well made some progress checked the continuity again on the coli and this time was making continuity ok between the yellow and green wires, found a slightly better but not exact wiring diagram for the bike and noticed the pink and green wires are terminate in a double socket at the battery end, there a corresponding green wire from the loom with a thick pink band around it which I had connected to the green wire in the double socket. So swapped the green with the pink band and connected it to the pink in the double socket and got one very weak spark. Tried a different spark plug and got a few more sparks but very weak and intermittent. Certainly starting to think the coil could be the problem having had that dodgy continuity issue then weak sparks when I could actually get a spark at all. Will check a few other things and see if I can finally get the correct wiring diagram. Thanks for all the help.
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Clean, gap points and set timing first as everything needs to be good to get a decent spark, i have a vague recolection of a condenser wire causing problems on one years ago
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Saw Millyard the other day on Henry Coles show and they were having trouble getting some old bike started, flux gap says Millyard, personally I can't ever recall hearing that expression before. I can't remember how he changed it now but it worked and the bike started first kick.
Possible it's the same for the C50?
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The flux gap is part of the flux capacitor.
But I’m not sure that the C50 had one of those.
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It's not back to the future Steve.