The units ought to be compatible. From memory there are slight technical differences but I do not believe there's any noticeable functional difference.

Going back through the forum comments muzza mentioned at one point that when he swapped gold and black he had to reverse the coil orientation (left became right etc.) to get it to work - might be worth trying.

 

I swap black and gold all the time they interchange no difference

 

Ditto. If there's any difference between black and gold units it's inconsequential.

 

So, if I read it right, you never actually ran the bike with the original CDI unit. Put it on a running bike, and nothing.

CDI unit is junk, mileage doesn't mean anything to these units, component ageing seems to be the main reason they're failing with regularity.

The fact that it sat in a damp shed for maybe 40 years didn't help much either.

 

Might be why it was sitting in the shed all this time - early life cdi failure ....
schematic is out there on the web for the original unit as well as some of the experiments.

eg 1980 Honda CX500C CDI Module

most common failure is one of the output SCRs followed by one of the diodes.
If SCR goes short - then it prevents charging of both caps. You should be able to test for this - as its only through a few diodes to ground - grab the power supply, sig gen and get to work on the bench.\


Rayman

 

Accept that your CDI unit is toast and move on to a modern system. In your case an Ignitec is probably the easiest as there is no requirement to open the engine to install it.

 

Do the stator test

Post the results

Then do the cdi output test if your stator is good

Then you will know what it going on for sure

 

Thanks for the replies. The CDi was tested on another bike but the same model as mine and that bike was fitted with the same CDi with the same part marking on the can. The 'test' bike ran fine with it's own CDi and ziltch with the one from mine.

I had a feeling of déjà vu here .. My mate bought a CB400N from a guy at work with less than 1k miles.... again left to rot in a damp shed. The carbs were horrid but after cleaning them, the bike ran OK for a week or so. Then the CDi failed.

Here is what I have done so far : Pics and write-up to follow.

I picked out quite a bit of the 'cheesy' type potting. I immediately noticed that the steel enclose was internally rusty on one side. I pick down as far as I could. Then I removed the black sleeving from the wiring and carefully pulled each individual wire through the grommet so that I could pick at the potting better around the fly-leads. I felt that by exerting force on the PCB this would possibly lead to grief as you have a large bonded area under the PCB. Drastic as it, is I slit the corners of the can with a 1mm cutting disc and folded the sides down, so that I could gradually peel the bottom ( normally top of the can) from the potting. This was interesting because there were several large voids in the potting between the PCB and the can. One was so bad that the bare underside of the PCB was exposed. When I designed potted 'gizmos' ( do you USA guys called them 'Hoo-dickeys' ) I used to heat the module to around 45°C and pour a small amount of epoxy encapsulant into the potting box with its PCB in it . I then vacuumed it to remove entrapped air, filled up with potting and then re-vacced and cured. The Chinese sub-contract manufacturer we used, hated me for this (I went over there 5 times) but I was insistent that if we potted stuff it must be done properly. It got to the point that I made them mark the potting box with coloured marks to identify that the various stages of manufacture had be adhered to (no pun intended) . So shame on you Hitachi for such bad encapsulation. Can you image if the 'Price of Darkness' Lucas in the UK had done this ?

Anyway, I sat yapping to my mate Roger yesterday afternoon and at the same time picking away further at the encapsulant. Before I knew it I had the underside of the PCB fully exposed and most of the components revealed on the top side. Who is this guy ? I hear you all saying but I actually quite enjoyed it. Just the kind of thing you can do while the 'other half' is watching junky TV programmes. I was worried that some of metal-film resistors may have got damaged in the picking so I desoldered one end of each one so that I could make measurements, but so far so good they are all coming out as preferred 'E' series values and no duffers ...yet.This also enabled me to clean underneath them. I will replace every resistor as a matter of course with modern equivalents 'just in case'. There seem to be quite a few glass passivated , controlled avalanche diodes on there ....I already use the BYW56 diodes, which are similar and readily available. There are no electrolytic capacitors on there to 'dry'up with age. Most seem to be mylar/polyethelyne film. Again I will measure and probably replace these as they don't cost much. Nothing on that module isn't replaceable with modern components and everything is discrete, i.e. no IC's. Nowadays, something like this would have a custom programmed chip in it that, if found to be duff, you haven't a hope in hell of getting a new replacement for ( users of Ultrawave late edition and Sono-Swiss industrial ...mega expensive .. ultrasonic cleaners beware !)

So what now ? ... I will clean up the PCB, replace all of the passive devices and try to identify any 'duffers' in the process , that may have been the cause of failure and then make up some kind of 'off-the-bike' test setup for it, once I have convinced myself what makes it tick. Then I will rehouse it in a sealed box encapsulated in silicone oil, so that if it ever fails again I can just remove the PCB assembly, clean with a suitable solvent and fix without all of the fun of picking at potting ! The original PCB by the way is a good quality epoxy-glass material and has PTH (plated through holes) so no worries there.

Where I worked in the 1990's , we used to 'pot' electronics in epoxy/PU, when really a conformal coating would have sufficed. This was purely because the owner of the company was protective of anyone copying/repairing our designs even though they were patented and he insisted that everything was potted. He made us use the rock hard when cured, mineral filled, type of epoxy resin too, that was only removable by hot refluxing with THF or similar nasty aggressive solvents until it went 'cheesy' and could then be picked off. Invariably though, components would disintegrate beyond recognition in the process.

I will write all of this up and post with pics etc. Sorry if it's been covered already and thanks on the cracking advice so far. Any advice on an off the bike test setup gratefully received. First thing (after repair) will be to simulate the alternator and pulser outputs and hook up to a pair of Honda coils I have spare.

Cheers for now ... Ash

I did a similar write-up on fixing Honda ignition coils for another forum :- here

https://www.dropbox.com/s/x0a4fcpmrwm3l19/Ignition coil fix.doc?dl=0

VIDEO LINK

 

Where I worked in the 1990's , we used to 'pot' electronics in epoxy/PU, when really a conformal coating would have sufficed. This was purely because the owner of the company was protective of anyone copying/repairing our designs even though they were patented and he insisted that everything was potted. He made us use the rock hard when cured, mineral filled, type of epoxy resin too, that was only removable by hot refluxing with THF or similar nasty aggressive solvents until it went 'cheesy' and could then be picked off. Invariably though, components would disintegrate beyond recognition in the process

Copyright & patents are virtually meaningless in electronics because as soon as you change one component value it is considered legally to be a different design so depending on what you were making and how competitive the field your boss could have been correct about potting to protect the designs. I worked designing speakers in the '70s & '80s and it was a truly cut throat business in those days. One of my employers caught a competitor going through their dumpster looking for customer lists (this was before recycling and shredders) so they took all the office garbage home where it would be in public view until the truck came for it. When I went to work at my last employer in that field the service guys had no end of problems because the boss insisted on gluing the crossover components onto their mounting plates with the printing down to prevent competitors from copying designs. Part of my job was evaluating competitors' products sent to us by customers who wanted us to produce equivalent (or usually better) products. After measuring the sample I would open it up, draw the schematic and call the boss to the lab to have a look before I put it back together so we could compare it with the samples I made. One day he realized that my schematics always had all of the component values, whether the parts were glued with the writing visible or not and I told him that I just measured everything in place. After that we instructed the crossover department to glue the parts on with the writing up and we were even allowed to order our electrolytics with colour coded wrappers so that it would be easier to tell which was which.

I am following this with interest, even though I don't have a CDI bike.

 

On the bike testing is about all we have. There are figures for these in the factory manual, but the figures can only be attained with the particular 2 meters that were used by Honda back in the day.

Figures from other meters are meaningless.

 

BTW: Many years ago on the ancestor of this forum and long before the Ignitec alternative had been explored or Ray had designed his stuff people were experimenting with repairing/replacing CDI boxes for these bikes. I am not sure whether this is the schematic of the Honda CDI or if it is what someone designed as a replacement but either way you might find it interesting

BTW: Welcome to the forum. Please add your location to your profile and your bike's correct model and model year (NOT year first registered) to your signature (see Forum Settings link in my signature) so that you don't have to remember to tell us every time and we don't have to keep asking when you forget.

 

Thanks Bob ..profile updated ... I am actually from the same town Hull where the famous on here 'Shep' comes from

Here is my newbie intro:

http://cx500forum.com/forum/united-kingdom-cx500/65066-hi-newbie-ash-east-yorks-uk.html#post555946

 

May be a bit of time before I report back on this as I need to order up the new replacement passive components. Everything seems to check out fine electrically so far though and in keeping with the circuit diagram that Bob pointed to. I have removed the three thyristors to check out by applying a load then gate voltage DC to see if they latch but the two main ones read correctly and both the same on my DVM. They are unmarked probably by Hitachi. to prevent copying .. I suppose given the numbers they could have ordered these unmarked from the OEM semiconductor supplier. All of the diodes test out fine on diode test on my Fluke DMM.

As I say, I will report back when I have the replacement parts fitted and the PCB totally cleaned up. Meanwhile does anyone have an indication of the voltage kicked out from the alternator? I would guess a couple of hundred volts or so AC but this is just a guess. My 400/4 CDi I designed in the late '70's used a similar capacitor and had an inverter ( like the 1969 Kwak H1's) that charged the discharge capacitors up to to 400 VDC. I assume the pulser inputs are inductive pickups but again any indication of the waveform these produce would be helpful.

 

the alternator output is around 90 volts ac at 4-5 k rpm

i dont get why you are wasting so much time fighting to keep a close to 40 year old system alive

when all that might happen is the next part of the ignition downstream will fail?

either get a know good used cdi box run the bike for a while on that while you saving for a rae san

or just move into a new modern ignition

unless riding the bike is not the point ?????

i and others have good used cdi boxes that we have taken off bikes when we refit new systems

 

Sorry but it's my inquisitive nature of why things fail being an electronics design engineer. Seems to me that the fault with my unit is water ingress due to poor original potting by Hitachi and probably nothing to do with the fundamental electronics design. The guy I loaned my CDi to had paid over well over 100 GBP for a 'guaranteed' to be working used one, that was found to be suspect when he received it and tried it out. Now that is all a waste of time and money in my book .... So no way am I seeing replacement used units on the likes of eBay, at bargain prices and as a newbie here it would be unfair of me to start asking if anyone on here is up for selling me one on the cheap. ... Also, unless you de-pot a used one you will never know if it was sealed properly or not when manufactured. If they had vacuum degassed them during potting , then that would have been a different story. TBH all of the active components in that module I should have stocks of anyway, so the repair will be very little in terms of monetary outlay. Just because a design is 40 years old it doesn't necessarily mean to me that it's obsolete or outdated. It looks like fairly high quality parts have been used. If I was seeing waxed paper dielectric capacitors or electrolytics in there then I would agree that the components are outdated. I can replace the passive components with modern equivalents, probably with high spec that the originals were ..... these modules will have been designed down to a price I imagine.

 

The output of the two ignition coils of the CDI-stator will be more then 90 V.

 

I'd expect around 150 from a healthy stator on low phase.

I have a bike here now with a low 5/9 figure outputting 75 volts and it struggles like buggery just to start. Connect a Raymodule PSU {around 185 volts} and it fires straight up.

 

most of the 400V systems will run about a 1uf cap -
these run 2.2 so the charged voltage is about 150 - 200 V or so - giving a nominal 40 - 50mJ spark ( thats tonnes)
the Ray-module PSU i designed runs about 185 - 220V usually depending on supply voltage and is limited by the SOA due to the need to withstand a short.

pickups are inductive - but not reluctance- they are driven by the passing leak magnetic field so they swing negative then positive as the "button" on the stator passes each one in turn.


happy playing.
Rayman

 

i like to ride way to much to fiddle like that with old stuff

i takes a lot of my time to develop and get to market stage any new products

some times it may span a few years so i concentrate any "spare" time on that

The "sport of wrenching " does not interest me

 

Good point. If you can't get hold of the known good CDI to verify that everything else is OK you should at least do the stator resistance tests. It would be a shame to put all that effort into rebuilding the CDI only to discover that one of the CDI related parts of the stator is bad and you would have to open the motor to replace the stator so that you can use it. Especially when alternatives are available brand new that will work without the CDI related parts of the stator.

 

You'll have to excuse Murray (the rest of us do, although sometimes I tell him there's no excuse ). Murray spends most of his time fixing other people's bikes, refurbing & customizing bikes to re-sell and coming up with products that are useful to the CX community including (among other things) Mikuni carb sets (including specific manifolds for each application) that are pretty much bolt on & go, spin-on oil filter adapters, "quick build" pipes (to eliminate the exhaust collector box) and his Quick Set valve adjusting tools. He has also been instrumental in convincing David Silver to have some formerly not available parts reproduced. And when he isn't doing that stuff he is the most prolific poster on this forum (where he is well known for helping out people that need some odd part) and he still finds time to spend with his family on occasion.

With all that on his plate, you can understand why he would rather get things done in the most efficient way so that he can still have some saddle time.

BTW Murray: We're talking about The Sport of Soldering here, not The Sport of Wrenching Its a whole other addiction...

BTW Ash: (Warning: blatant plug coming) In case you are wondering about The Sport of Wrenching, someone on another forum used the phrase a few years ago and it stuck with me. Later on I designed a graphic for it, just thinking it would be neat to hang on the shop wall and shared it on a few forums and a bunch of people asked me about shirts with it so I opened an online T shirt shop which I have since added a bunch of other (mostly CX related so far) designs to.

 

Meh i just finished a,1963 y22 yamaha

The mighty 80

As to the sport of soldering

Nope

 

I realise that what I am doing to the Cdi is madness but from the age of about 4 I have been taking stuff to bits and I am 63 now! I didn't mention that from the same shed and garden I found a CB72 & a CB450K0 Black Bomber all in pieces. I just rescued them and the CX before the local council moved in to skip them Piecing those two bikes together armed with the Honda parts book is proving immensely pleasurable .. a bit like 2 1000 piece jigsaw puzzles. There's an old chap in his mid eighties when he passed away, up there chuckling to himself . Amazingly though it's all coming together!

Good on you Murray for getting David Silver to make repro parts..... I 1st bought from him when he was trading from home in his spare time.. way back in 1986 ! I was lucky enough to get an invite to the launch party at his museum ... he's certainly kept a lot of our old bikes on the road !

Cheers for now ... Ash

 

Here's those static resistance checks.

 

Brilliant .. The bike is in storage but I can get to it early next week armed with my trusty Fluke DMM.

As far as I am aware the engine has not run since 1982 so I am hoping for the best. I have only turned the crank very slowly using the 17mm bolt located inside the inspection cover. I have not hooked up a source of power to it yet. The Cdi saga was initiated by loaning my CDi to a dear friend who was having running issues with his CX.

Thanks for all of your kind help so far BTW

 

Before you turn it over much, even by hand you might want to consider doing this

(from http://cx500forum.com/forum/technic...orum/89369-gl500i-general-questions-about-starting-non-runner-2.html#post826113 )

This is just my "strong" recommendation. The Cam shaft sits in the "valley" between the heads usually this valley retains a small amount of oil that's picked by camshaft during engine start. Over time the oil drains from this valley leaving the camshaft high and dry and it take a little time for the oil to make back here when you try to start the motor scoring/pitting of the cam lobes can occur quickly. Pouring some oil in just ensures the camshaft has sufficient lubrication immediately.

 

Thanks for heads up on engine oiling before attempting to start Bob. I will definitely do that.

I now have a squeaky clean bare original PCB with all of the solder in the holes removed. I managed to retain most of the silk screen idents on the PCB. I photo'ed the depotted PCB module are various stages and printed high resolution colour photos. As I removed each component, I tested it, noted the value and the circuit reference and then taped each part in its location on the picture, so if any double-checking necessary I am OK . I measured all of the capacitors and they all seemed preferred values (inc the 0.15 uF on attached diagram from the Dutch forum) but pretty sure I had a couple of 0.1 uF's as well as 0.047's. (I need to check this all out when I am back at work on Monday) I think I will replace all diodes with BYW56's http://www.vishay.com/docs/86049/byw52.pdf )..anyone got thoughts on this? Seems the originals were 400v versions. Both the output thyristors and 2.2uF caps metered out just fine with my Fluke DMM.

I will post pics of all of my efforts next week.

This is the Dutch Circuit I am comparing with:-

 

this is going to be painful

you want a working cdi??

 

Thanks for the kind offer Murray but I am not a quitter and I think I have done the hard bit. Compared with tracking down decent quality standard exhausts, fork stanchions and standard front fender for it (now done) the CDi bit is child's play ! The chrome cycle bits may be plentiful in the USA but bloomin hard to find in the UK in really nice condition. German eBay classifieds was my saviour in the end. Buying for us in the UK from the USA is now a no-no really because of high import duties and shipping costs.

BTW my wife bought a, non-working for decades, 1937 valve radio at a boot sale last year. She joined a vintage radio forum with a view to helping us get it working and she got replies like 'Your husband may be an electronics engineer, no disrespect but valve radio technology is a whole different ball game and this will end in tears" ... well one month later they were 'eating their words" 'cos I refurbed it (similar thing bad capacitors and audio output transformer) and it now works great. All of the valves worked fine and I guess the thyristors in this CDi will work fine. I found tons of posts on here where people have done a lot of the groundwork which is proving to be a great help.