Wiring help?

JMH · Two Stroke Sniffer Joined: 17 Jan 2006 Karma :

Hey all- I've got a wiring situation on my hands that I can't seem to figure out. The bike is a 1982 Honda CM200T. The cdi unit died on me a couple of months back. I've replaced all the components in the electrical and ignition system, but I'm still not getting a spark from the new box. I've replaced the coil, the rectifier/regulator, checked the wires and fuses, verified the pulse generator was working (off the shaft). Still nothing. The cdi box I got from the shop is from a 1982-1983 Hoinda CM250. Different bike, but the box is essentially the same thing. The wires plug in at different spots, however.
I've rewired the plugs to match what I believe is the proper order according to my Chilton's manual. The problem there is, the wiring diagram shows the wires connected in a left-to-right fashion, whereas the plug itself is square. I made a note of which wires went where on the original plugs, as compared to the diagram for the CM200T, and used that as the same model for rewiring the plugs to fit the CM250 box. Still, I get no spark. Also, I've noticed the starter button doesn't work either. There is no drain on the battery, not even a sound from the solenoid when it's depressed. Any ideas about what's going on with that? Could it tie in with the cdi box problem? Does anyone have a 1982-83 CM250 that they could use to verify the wire order on the cdi plugs? Any help would be appreciated. I've had this bike together for awhile now, but can't seem to get it to start again. Thanks!

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

You need to wire them according to what the wires connect to, not the order they are in in the connector blocks (which as far as I can make out is totally random).

I don't have your wiring diagram in front of me but if they are broadly similar to the smaller hondas I have worked on the wires coming out of the CDI should be connected as follows:

Green to earth.
White and Black to alternator source coil.
Green/white and Blue/yellow to pickup coil.
Black/yellow to ignition coil.
Black/white to ignition switch.

Obviously, If these colours are different to yours, ignore the above.

Is the source coil generating power for the spark when the engine turns over? You should get a voltage between the white wire and the black wire when the bike is kicked over (here is where an analogue multimeter comes in handy, you can see the needle jump as you kick the bike over).

Tested the coil itself?

Everything else working ok? (lights, horn, neutral light etc).

The starter circuit is pretty much seperate from the ignition circuit.

Check the starter motor by shorting across the terminals on the solenoid (you will see sparks). This connects the battery directly to the motor, it should spin over regardless of the position of any switches. If it doesn't, your problem is in the heavy wiring between the battery and the motor or the motor itself.

If it does spin over, the problem is in the switching circuit. Easiest to test it one step at a time. Get your voltmeter and go through it in stages to see where the 'blockage' is.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

JMH · Two Stroke Sniffer Joined: 17 Jan 2006 Karma :

The ends of the wires are all securely attached to their proper components. The problem lies with the wiring of the replacement cdi box itself; it's for a CM250, not a CM200. Both boxes have the same number of connectors, but the 250's are flipped in their orientation on the actual box. According to the wiring diagram in the Chilton's manual that I have, the wires go to the same places as on the 200, but they connect to the 250 cdi box in a different order than they did with the original box. The diagram shows all the connections from left to right (1 plug with 4 wires, 1 with 3), yet the order of the wires within the plug is different than the diagram; even moreso since one plug is organized in a top-to-bottom fashion, and the other one is completely square! It's a friggin' nightmare!
The coil, plugs, wires, and battery are all brand new. The rectifier is a used one, but the specs for it fall within permissible boundaries. Likewise, the impulse generator which reads off the magnet down by the alternator also was within serviceable specs. I figure either the new (actually used) cdi box is bad, or there's something I'm somehow overlooking. I'm not getting any spark at all, yet the lights and all other electrics work fine.
I may check the starter circuit as you described. For the life of me, I cannot fathom why it won't start again.
I had the bike running several weeks ago (it had been in pieces for about 7 years), and it was running fine. Problem was, I had failed to hook up a kill switch in the proper circuit. I mistakenly turned off the power switch, which resulted in shutting off the battery, yet the bike continued to run. I knew at that point I had just fried some of the electronics on the bike. I've since replaced all the parts affected, but haven't had any luck with a cdi box for that model. No bike shops around here stock the part, nor can they get it. My best bet was a used unit from a CM250, but due to the difference in the plug-wiring order, I still cannot get the bike to turn over. As per an earlier suggestion on this board, I sent an e-mail to David Silver Spares; they apparently have the part in stock, but I want to make sure it's compatible. I know some of the bikes over here in the States have dissimilar model numbers compared to those in Europe. I was just trying to make the 250 box work, but I don't know that I can. I may have no alternative but to buy a unit from DSS.
Your wiring schematic was spot-on, by the way! Thanks for your assistance in this matter. I'm just dying to get riding again. I've got 2 bikes, no car, and both bikes are down now. And having to ride a bicycle 9 miles each way to work every day is getting old real fast...

--JMH

finpos · World Chat Champion Joined: 13 Sep 2005 Karma :

On a bike of that age with cdi, the ignition system will be completely seperate from the rest of the bike's electrics (the stuff connected to the battery). The only time they come near each other is in the ignition switch, and that's just normally to ground the pulse input to the cdi so the engine stops running. You've seen this in action when the bike continued to run despite you setting up the kill wiring incorrectly.

So, to save yourself a shed load of hassle, I'd try going back to your original CDI!

because your starter motor is showing no life, i'd be inclined to be looking for a wiring fault somewhere around the headstock or right grip. Just be systematic and trace every wire with a multimeter - don't rely on visual inspection.

finpos.

JMH · Two Stroke Sniffer Joined: 17 Jan 2006 Karma :

The bike was rebuilt completely custom, so the switches and such aren't all still on the handlebars. The ignition switch is simply a 3-way toggle hidden along the framework beside the seat. The (new) kill switch is a small push-pull switch located behind, and to the right of, the seat.
I'll check the wires along the starting circuit. Maybe the switch went bad? It's a simple one-touch momentary starter button rated at 15 amps. Maybe the voltage surge from disconnecting the battery could have fried the switch? Man, I still can't believe I did something so stupid!
Thanks for the advice! I'll try your suggections out.

--JMH

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

Right. Something not ringing quite right here.

Your kill switch should be MAKING a connection when activated. It should connect the coil input to earth.

The battery and charging system is irrelevant when it comes to the bike actually running. There are seperate source coils on the alternator which generate the power for the CDI.

You should only need a two-position switch for the ignition (with six terminals on it). In the 'off' position, it should be making a circuit connecting the coil to earth and have an open circuit for the lighting. In the 'on' position, these two are reversed.

I think you are making life unecessarily complicated by trying to use the CDI connector blocks. Cut them off and use some nice non-insulated bullet connectors.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

JMH · Two Stroke Sniffer Joined: 17 Jan 2006 Karma :

Yeah, the kill switch (when activated) connects a ground wire (dark green) to a black & white wire (which connects to the cdi unit). That one I was able to wire up properly.
The ignition switch is a three-way switch (left is ignition on, center is off, and right activates a mercury-switch activated siren if the bike is tampered with. Poor-man's alarm system). So when the switch is activated for ignition, the lighting circuit turns on, and the power (should) be ready to fire up the engine. It all worked before I stupidly turned off the ignition while the bike was running, and fried the electrics.
As for the blocks, yeah, I eventually got tired of screwing around with them and went with some insulated and sleeved connectors. Boy, this project is turning out to be more fun than a root canal without Novocain, huh?
Feel like I'm beating my head against the wall, like I'm overlooking something small. Getting ready to check the starting circuit and whatnot now...

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

Right. You have MS paint on your computer right?

I made a start for you. If you wire this lot up your bike should run. That is all you need. The rest is decoration. Get that working first then do similar diagrams for the other systems on the bike. (one each for charging, starter, and lights).

Work through them one at a time. (it is hell of a difficult to test the charging system without a running engine, likewise difficult to test a lighting system without a functional charging system etc.)

Once you have drawn them up like that, you will have a very good idea of how everything works, the problem will most likely jump out at you. Then you just need to join the diagrams together to get a full, colour wiring diagram for your bike (which you understand because you drew it).

Could you also do me a favour? Your posts are quite long and technical, dividing them into paragraphs would make them a hell of a lot easier to read.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

JMH · Two Stroke Sniffer Joined: 17 Jan 2006 Karma :

First, I'd like to apologize for the lack of paragraphs. I should've probably been hitting the return key twice, rather than once, between paragraphs. Sorry about that, man.

I've got the bike wired up just like your diagram. All the wires are going to the right places (I made double sure of that as I was wiring the bike up initially).

I made a diagram to show you what I'm having trouble with. The diagram shows the wiring schematic for both the CM200T and CM250C, as they appear in the Chilton's bike manual. Beneath those diagrams are crude representations of the actual cdi units. The plug jacks do not read left-to-right, as they do in the book diagram. So I made notes of where each wire actually was, and applied that model to rewiring the plugs to fit the CM250C cdi box.

However, that doesn't seem to work! I have no earthly way of know which wire is supposed to go where on the CM250C box because the actual box and the diagram for it look nothing alike, nor do they follow a linear pattern (instead of 1234 567, as in the book, the plugs are more like 213 6574. Confusing, isn't it?)

I'm about ready to rip the hair out of my skull because this is driving me absolutely bonkers. Any tips? I've tried swapping the wires around several times, but there are way too many combinations to go through...

Thanks in advance for your assistance thus far! It's greatly appreciated!

--JMH

JMH · Two Stroke Sniffer Joined: 17 Jan 2006 Karma :

Slight mistake in the illustration! On the image of the actual cdi box for the CM200T, the three-pin plug should read (from top to bottom): Dg, G/W, L/Y. Sorry about that! Got the Layers mixed up when placing everything...

--JMH

finpos · World Chat Champion Joined: 13 Sep 2005 Karma :

Well...

Firstly, I'd stick with my original recommendation - Go back to the original CDI box until you are 100% sure it's dead. Because you are working with a loom which is an unknown quantity, I'd run seperate wires between the components to test it.

If you want to bravely persevere, DON'T rely on the positions of the terminals or the colours of the wires to guide you. You must figure out the wires by function. Elsewhere there's a list of wire functions, e.g.:

Wire to ignition coil
Wire to ignition switch
Wire to pickup coil
etc.

You need to sit down with your two wiring diagrams side by side and trace each wire from the cdi to its termination, and write down what colour does what.

I'm willing to bet that the looms off the two bikes are incompatible in terms of colours. I'm almost certain that the two blocks on each of your cdi serve the same functions:

the one with 4 connectors is for the link to the stator and pickup
the one with 3 connectors is for the link to the kill/ingnition sw/coil.

If that's the case, then a quick look at your diagram will tell you that you are barking up the wrong dog trying to match the colours!

finpos

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

As finpos says, it would be better to see where the wires from each are going in the diagram for that bike and go by that. (label them in your head 'wire to pulse coil', 'wire to ignition switch')

That said. Honda are generally pretty good at using the same colour wire for the same thing on most of their bikes of that era. Green is always earth, red is always live, white (and yellow) on black is always coil supply, orange and blue for flashers and so on.

Could be there is a problem somewhere else in the system (Plug, plug cap, HT lead, coil, source coil) or that the CDI is not functional. You need a specialist meter to test a CDI unit so the easiest way is to try a working one.

Here is a handy link to a website all about vehicle wiring.
https://www.btinternet.com/~jhpart/bkwirec.htm
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

JMH · Two Stroke Sniffer Joined: 17 Jan 2006 Karma :

The color-coded wires are connected to similar components on each bike (green to ground, black & yellow to coil, etcetera), but they connect to the cdi unit in a different order.

All other components on the bike (regulator/rectifier, ignition coil, pick-up coil, etcetera) have either been replaced with new units, units tested and verified to be functional, or they were still functional to begin with (and this was checked out with a multimeter).

I had attempted to turn the bike over using the new components, but still using the stock cdi box. There was no spark at all, even when kick-starting the bike. I then tried it using the replacement cdi box, and the results were the same.

When I first got the replacement box, I was told it was for the Twinstar, so I simply plugged it into the stock harness. I later was told it was for a CM250C (hence, why it wasn't working yet). Could this unintentional "miswiring" have caused the cdi unit to break? After learning it was for a different model, I tried to rewire my bike's plug ends so the wires would go to their new spots on the replacement cdi box without too much trouble. Still, there is no spark.

I was told the replacement box came from a functional bike, but I have no way of comfirming this. The part came from a salvage yard. Should I simply say "the hell with it", and get one from David Silver Spares (whom I am awaiting a response from)? Neither any of the bike shops nor any bike salvage yards around here have, or can get, a stock replacement cdi box for a 1982 Twinstar. I was told Honda doesn't even make them anymore, so my chances are pretty slim.

I suppose I'll just have to try to get another unit from DSS. I'm not having any luck trying to get one stateside. I'll check out that link you provided, Stinkwheel.

Thanks again to both of you for your continued assistance on this matter! It's much appreciated! Hope I can reciprocate in kind.

--JMH

finpos · World Chat Champion Joined: 13 Sep 2005 Karma :

Right then:

One question you've not answered is:
Why did the bike stop running?
You've described how you got some wiring mixed up, cut out the battery/charging circuit, and the engine kept running. Presumably, you stopped it somehow! Then it simply wouldn't re-start?? I think we're missing some important information here.

Secondly, I'm a tight bugger and would not go buying any more CDIs until I was sure I had two broken ones. They are pretty tough things.

This is what I would do:
Crack open the flywheel cover. You should then be able to actually see two wires going into the stator somewhere that power the CDI (I suspect B/w and B/Y) and two wires going to the pulse sensor (suspect W and L) Connect these up using seperate wires if necessary to your original CDI in their original configuration.
Then, Disconnect the Kill wire (G?) completely.
Then, Try to figure out what the ignition wire (GW?) does. I EXPECT that the ignition switch grounds it, but I cannot be 100% sure. If that seems to be the case, then disconnect that wire as well.

What I'm not clear about here is if your cdi needs a seperate earth. It's possible that one of the wires e.g. G or GW is not as described above but is supposed to be an earth. Your wiring diagram should tell you. Possibly the CDI is earthed though it's mounting (you have bolted it on, havent you?).

It's also worth running a extra earth wire between the frame, the engine and the CDI earth, just to be on the safe side.

You have now got everything you need to make a spark. Disconnect the coil wire (LY?) from the coil and hold the end of it very near to the engine casing. Get a willing assistant to jump on the kickstart, and you should see a pathetic little spark. If so, well done, the CDi works, look for a problem elsewhere!

finpos.

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

Finpos. I think you could be getting a little confused with your wire colours. I have worked on various 1970's and 1980's Hondas and dark green is always earth. That one I can be sure of.

They also use a black wire with a white tracer or a black wire with a yellow tracer to supply power to the ignition coil.

This is true for C90s, C50's, H100s, CB100, CB CD CM 125s, CB250N.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

finpos · World Chat Champion Joined: 13 Sep 2005 Karma :

Not getting confused - just having a guess at the colours. Your superior knowledge is well and truely bowed to. That would explain why I had a seperate ignition/kill and no earth Smile

JMH - Hope I didn't confuse you - I did try to make it clear I was having a good old fashioned guess. Whatever you do, don't take my post as gospel, satisfy yourself the colours are correct from the wiring diagram.

finpos

JMH · Two Stroke Sniffer Joined: 17 Jan 2006 Karma :

Well, my buddy Dave and I disassembled the carb and cleaned it out, then reattached it to the motor (I'd been having a hard time keeping the bike running, and it had sat for about 7 years before I got a chance to rebuild it!)

I fired the bike up, and after some initial roughness, it smoothed out and ran extremely well. We let it run a bit before I decided to shut off the bike.

Now, the bike is set up to be keyless- you simply flick a switch to get the main power turned on. I failed to wire in another switch to connect the ground to the kill circuit, and figured that merely shutting off the ignition power switch would do the trick.

I flicked the switch, and saw the bike's voltmeter guage drop to zero. Yet the bike continued running! I immediately realized I had just screwed over the electronics, and hit the ignition switch back to the on position. Alas, too little, too late!

I ended up having to turn the fuel off in order to basically starve the engine, causing it to finally shut off. Devices which got jacked up by my mistake? The rectifier/regulator, the ignition coil (I lost power to the secondary circuit) and the cdi unit. After getting the bike to finally turn off, it refused to start again. This is why I think the ultimate problem in this case is the cdi, since all other components have been replaced.

So now I have a completely rebuilt bike that cannot run. As per an earlier suggestion by another board member, I contacted David Silver Spares, and they had the exact cdi unit I needed. I'm fairly certain that replacing that piece of equipment will allow the bike to start again.

Oh, and if you're curious, I've posted some photos of the bike in the Photos section, under the title "1982 Honda CM200T". It's way different than the stock version! I'm just chomping at the bit to go riding on it...

--JMH

JMH · Two Stroke Sniffer Joined: 17 Jan 2006 Karma :

Hey guys-
Just a quick note here. Got the new cdi unit from David Silver Spares today. Put it in the bike about 20 minutes ago, shot a burst of starting fluid into the intake, and she purrs like a kitten! I'm so glad to have it running, I'm going to get dressed and go out for a ride (it's 1:30am here, and I have to get up for work in about 6 hours, but who the hell cares about that now?) Just wanted to say "thanks" for all your assistance (and I had to double check a lot of the wiring based on your recommendations, believe me!)

Thanks again, and I hope to be of assistance to you one day as well (you guys need any custom decals or artwork, let me know. That's what I do for a living!)

--JMH, going for a ride!