Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: philward on April 22, 2019, 10:20:16 PM
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Out for a ride today on the standard K2 and it started irratically mis-firing and surging/slowing. Managed to make it home and checked the usual things - cleaned plugs, checked petrol tap filter, points and timing. Noticed lots of arcing on 2-3 points and guessed it was the condenser - changed for a spare and cured the mis-firing. The original condenser (and replacement) are after market and so in line with the advice I've read on the forum, have been trying to source some genuine condensers for piece of mind but the price at DS is about £30 each!
Can anyone recommend a proven alternative? - as at that price, I'll just buy an electronic ignition (have one on my CR750)
Cheers
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I fitted after market condensers from DS in Febuary and they are working fine, £19 inc' postage and VAT for the pair.
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That's what I have in - just worried that they have only lasted 1500 miles and might let me down again (can't remember ever changing condensers in 40000 miles I did on my 500Four back in the 70's) - might just be bad luck
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Or maybe good luck in the 70s doing 40000 on the same condensers.
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I fitted after market condensers from DS in Febuary and they are working fine, £19 inc' postage and VAT for the pair.
As a follow up to this post and my reply to it, the after market condensers from DS failed after 200 miles, bought another set from ebay at £16 delivered, one of these is now giving trouble, miss firing, back firing, so the last one is now fitted and cured the problem for now, but for how long, i'm fearfull about going any distance from home as the first time it happened i had to ride home ten miles on two cylinders. They do say buy cheap buy twice, but Silvers genuine Honda condensers are now £72 delivered, and their pictures look the same as the after market ones. Anyone else having this problem ?
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I am going to fit a pair of range rover condensers by the coils, i had to get 10 so you can have 2 for a fiver plus postage
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Great, thanks but how do they fit, is it a straight swop ?
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You just bolt the condensers to the coil mounr and connect the leads into the leads to points
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There are other threads on failed condensers. Could there be a basic problem such as a faulty generator, rectifier or coil causing it. Or even a bad plug cap or poor plug cap connection cause some sort of back surge. A basic way of testing each might be useful.
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As I understand it, increase of resistance in HT circuit along with minimal specification plug gaps will give the triggering/ switching components an easier time. That's for both points and condenser or electronic.
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Very interesting overview to consider
http://nonlintec.com/sprite/cap_failure/
It's not unusual it appears that condenser quality is an issue for others too.
Interesting that the physical construction in his view is not particularly tolerant to vibrations, and possibly the differential between originally supplied Honda components.
It looks like much of currently available components are just not matching OE fit regardless of how much they cost.
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Would anyone care to dissect one of Bryan’s Range Rover caps?
Thanks for posting that Nigel, it’s the sort of non-emotional investigation we need.
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Very interesting overview to consider
http://nonlintec.com/sprite/cap_failure/
It's not unusual it appears that condenser quality is an issue for others too.
Interesting that the physical construction in his view is not particularly tolerant to vibrations, and possibly the differential between originally supplied Honda components.
It looks like much of currently available components are just not matching OE fit regardless of how much they cost.
That is a very interesting article, i now know what is going on inside a condenser and why they fail. We are at the mercy of cheap shoddy goods, probably made in China regardless of what it says on the box.
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I used to use Lucas car condensers, as fitted to Morris Minors or Landrover petrol engines. Used to cost around £1 each at the time, and genuine Honda ones were around a tenner each at that time. Like Bryan I fitted them beside the coils, and they never failed there. I think the heat and vibration of the original location was often the reason for failing.
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I'm wondering if Hondamans system protects the condensers better due to the reduction in voltage etc.
I've asked him as I haven't heard from him for a while about the systems I wanted to order.
Yes, it (as far as I can determine) takes the condenser completely out of use while it's in operation. The points opening is just used as a signal of timing to his electronics, so switching virtually no load at all (the reason a condenser is needed) just being used to provide a pulse on time to trigger the additional system which are doing all the donkey work in switching the coils.
His system replicates points open time, dwell etc electronically if I understand the details correctly.
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In a very similar way, the rover V8 electronic distributor uses one of these in the link.
https://rimmerbros.com/Item--i-STC1184KBP--SelectedCurrency-1?gclid=EAIaIQobChMIgpvQhOTR6gIViK3tCh0CfgS0EAQYAiABEgJlJvD_BwE
It effectively does the same as the hondaman unit (but for just one channel) takes a pulse from timing trigger, which is a non contact magnetic type instead of points, then uses the above unit to handle all the coil switching load.
In theory, you could just use two of these, one for each point set to run the Honda coil switching, that's if they'll accept the points pulse form.
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I have very old condensers in my bike and they have never before failed. I like the tip about keeping old ones, seems to be the same for a lot of electrical components nowadays.
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During a service I renewed my original Honda points and condensers with Daiichi, Japanese made stuff.
About 1000 miles later the fuel consumption went up and I discovered the timing was out slightly and points badly pitted compared to the original Honda stuff I'd just removed (which were probably OK).
Fitted a digital Boyer back then about 8 years ago and no problems since.
Just looked at the old Honda points and they are stamped with 'TEC' brand mark, the condensers have no brand mark tho.
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There's some shocking ignition components about generally.
Rotor arms for a car engine I work with are a prime case, with some coming out of their box pre-failed ;D and even if they do work it's not for long. Somebody's making the crap though and many supply lines stock them. Borderline criminal if someone gets a failure at critical traffic point, perhaps with their family in the car.
Diagnosing it on forum too is a problem for the less skilled, as we can see and know it's failed from tracing the HT path, but they then buy a "new" rotor arm (that's failed prior to delivery ;D) put that in and surprise, surprise it doesn't fix it. Drives us all nuts on the forum.