Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: florence on September 01, 2023, 12:09:48 PM
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Over the years I have had a lot of trouble with errant sparks, especially when damp or wet. A year or so, I replaced the original coils with aftermarket ones but not completely happy with their performance either. I have new plugs and new caps. Periodically, number 1 cylinder drops out with a weak spark. I tried reducing the spark plug gap which has helped.
Does anyone have a recommendation for good reliable replacements as I am not sure about the quality of the ones I am using added to which they don't fit correctly on the frame anyway.
Thoughts??
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I think I read here somewhere that a firm is selling the original brand ones sourced from the original Honda manufacturers - pretty sure someone here will know who - that might have been for the 400 though.
I fitted these Hendlers to my 500 as a short term fix, the bolt mount centers are 10mm narrower so I fitted a short link bracket between frame & coils. Can't comment on the long term reliability as I only did a few miles on them before I stripped my 500 down.
https://www.ebay.co.uk/itm/151925589049
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I bought a pair from Boyer electronics for the 500,
But a cheap Chinese copy for the 200,
Purely as it had a low primary resistance, it cured all the running issues I had,
Sent from my SM-A546E using Tapatalk
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Thank you. Does anyone know what the primary resistance should be?
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You tried fitting a silicon sleeve over the HT lead like the original Honda ones had? If you can fit it right up to the coil and right up to the sealing rubber on the HT cap that should stop any arcing
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You tried fitting a silicon sleeve over the HT lead like the original Honda ones had? If you can fit it right up to the coil and right up to the sealing rubber on the HT cap that should stop any arcing
Good idea, there is a gap, might use shrink tubing. (I was worried I might seal moisture in)
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Do the Ash repair on standard coils with the sleeving
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I've done about 4 sets of standard coils using Ash's guide and all good so far. As you are fitting new leads, it should logically sorrt the arcing. Coil values are in Ashes guide in 'Ash's Dropbox'.
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Weak spark can be caused by the long current path to coils. I've fitted a fused relay to supply the +12 direct to coils.
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For a good working ignition good and firm contacts are essential. It's well possible that someone attributes improvement to a new part he or she has fitted, while in reality the connection was redone and now as it should have been before.
Here are a few connections which deserve attention:
HT lead - plugcap (you may also check the caps resistance).
The Y connector primary side where the Bk/W wire devides in two.
Contactbreakers: the little bolt in the breaker must be securely fastened to prevent a wandering dwell
make sure their connectors do not ground intermittently.
In general: plugcaps are the CB500/550's Achilles heel.
My approach always is, that I don't replace any part before I have diagnosed what is wrong.
I have not been lucky with R(esistor) spark plugs.
Having run OEM and 3Ω coils, I can conclude that the primary resistance doesn't matter so much, as long as it is in between 3 and 5Ω.
Be aware that some aftermarket coils may have the connector 'gender' wrong.
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Good point about coil Gender I had to switch the coil connections on my aftermarket coils, luckily there was enough room in the wiring to do it.