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Discussion Starter · #1 ·
As I have said earlier, I am having electrical problems I think. My father-in-law feels the problem lies deep within and wants to take of the flywheel to have a look in at the stator and beyond. I am not so convinced.

Now, I have had this bike running, but for a while I couldn't get a spark, even with a new battery. Now I can get a weak spark in the left side but none on the right. Would this indicate an ingnition coil problem? Am I right off there?

Sean
 

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that's not enough information to tell yet, from what you've described it could be:
1 a bad connection (positive or ground)
2 a bad coil
3 a bad or improperly set point for that cylinder
4 a bad condenser
5 a bad high tension lead
6 a bad spark plug
7 a bad spark plug cap
8 or a combination of any of the above

if your problem is the same with a new battery then your stator is not causing the issue. your bike will run with no stator at all so long as it has a charged battery.

my best guess would be on the points being either bad or misadjusted combined with corroded connectors on several of your wiring terminals

buy some electical contact cleaner and dielectric grease at the auto parts store and take apart your wiring harness one connector at a time , clean and grease each terminal then reassemble (make sure all the cleaner is dried off before you run current back through anything!!!)
Then test your points with a test light or voltmeter (get a manual if you don't know how), and set them.
fully charge your battery then reassemble and you should have good spark.

if you still don't have a good spark you've eliminated options 1 & 3 above (which account for about 80% of all ignition problems in these old Honda's) and you'll need to perform tests on the other 5...send me an email if this doesn't work and I'll give you tips on how to test the other stuff.
 

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Thanx, had my head stuck on CB450 when answering. so yes, drop the points and condenser bit which means that you have a trigger and ignition box. In my experience you need more advanced testing eqipment to test triggers and ignition modules. if memory serves... to test a trigger you need a voltage gauge that can capture and read maximum output (just like a compression tester gives you a "highest reading obtained") where as most common voltage meters give you only instant in time readings. similar story with the ignition module. I'm not completely sure about the CM400T but every other Honda I've worked on has had a negative ground signal sent from the ignition module to the coil (yellow with blue wire for the left and blue with yellow wire for the right) the coils are positively charged from the ignition circuit (black with white wire to both coils) the coil is "told to fire" by the ignition module when it recieved a negative signal that releases the spark to the high tension side (plug)...all of this means that you need special testers to read that negative signal from the ignition module to the coil.

I'd still start by cleaning all the terminals in the ignition circuit and don't forget the main wiring harness ground to frame and the battery ground to frame.
 

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Discussion Starter · #6 ·
Thanks for all the help. I am in a bit of a tussle with my father-in-law about what to do next. He took one look at the list by 'outobie' and its all wrong for my bike. He told me that, once started, the bike can run without the battery but must have the alternator. I love the guy, but once he gets his back up he can be stubborn. I think he got offended that I went to 'another source' that contradicted his advice. He is determined to take the rotor off and fiddle underneath, believing that moisture build up behind there is the problem (There was water in the area when we took of the cover... It obviously wasn't sealed well).

Anyway, I am going to clean everything to start, as you suggested (He says not to as I can damage things). I may take the CDI and the ignition coil to my local shop to see if they will test them.

Any other advice would be appreciated... I dont have the knowledge and now I have to deal with a p. o.'d father-in-law who wants to tear the whole bike apart to change the air filter. Makes it even more interesting! Once I have done those things, if I have problems I'll get back to you.

Sean
 

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Sensei
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Your father-in-law is correct...sort-of...... The ignition WILL fire as long as the coil wire is NOT grounded...IF you can get the alternator spinning fast enough to start producing enough electrical energy to initiate the process....The "kill" grounding is normally caused by either the "kill" switch, or the ignition switch in the off position.
It has been my experience that moisture or rust build-up inside the rotor will cause intermittant or failed ignition......
 

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to your father in law's credit he is partially correct about the bike being able to run without the battery. the stator doesn't put out a full charge at idle. the engine would have to be spinnig at about 3500 RPMs or so before the stator puts out enough voltage to properly power the ignition system. the bike doesn't actually care what the source of electricity is so long as there is a constant supply of 12volts. that supply can come from the battery or the stator (as long as the regulator rectifier are functioning properly)

I recently read a story about a guy who rode cross country and brought along a small gasoline power generator in his saddle bags (so he could listen to the radio and have electric lights while camping at night or something like that. I guess he never heard of batteries)...any how...along the road his stator quit on him which caused his battery to eventually go dead two days ride from nowhere.

according to the story, he rigged up the generator in his saddlebag to the wiring harness and made the two day trip back to civilization without missing a beat

by the way, you don't take the stator off to test it. the stator produces AC current and delivers it to the regulator / rectifier (should be 3 yellow wires from the stator to the reg/rec.) with the engine OFF disconnect the stator connector to the reg/rec and take a voltmeter and check for continuity between each of the 3 yellow wires (sepertely) and ground to the bike frame or to the negative battery terminal. (this is an Ohms test). you should get a reading between 0.1 and 1.0 Ohms. next, test for continuity BETWEEN each of the three yellow wires. there should be NO CONTINUITY. if the stator passed both tests then guess what...your stator is working properly. the condition that 66Sprint mentioned above would show it's self by failing the second test I describe above. If you have continuity between between the yellow wires then you have a short in your stator windings

Please keep in mind that this test has nothing to do with why you have no spark but should satisfy your father in law that the stator either is or is not working properly. the only way to eliminate the stator as possibly contributing to the problem is to disconnect it as I suggested in my earlier response.
 

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once you get past the stator issue you should take apart the terminals to clean & grease them in order. find a wiring diagram for your bike and follow the current flow from the battery and check for voltage at each connector in the sequence in which the current flows. Start by making sure the battery is properly connected to the wiring harness and the ground from both the battery to the frame and THE WIRING HARNESS TO THE FRAME are clean and tight. Then work your way through the wiring harness; starting backwards from the known problem (spark plugs, sparkplug caps, high tension leads, coils, CDI box, etc, until you get to a component that is functioning properly with good voltage.

for instance, if you have strong voltage (a reading the same as when you test the battery directly) to the CDI box (black wire with white stripe) but not to the same black with white stripe wire at the coil then you know the problem is in the wiring harness or connector between the junction of the black with white stripe wire to the main harness and the coil, etc.
 

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Discussion Starter · #10 ·
Thanks again. As i said, my F-I-L is a great guy, but I know since he's retired he makes every project much bigger than it needs to be (I think it is a way to fill time). He has a lot of knowledge about elelctrical things in general, but not bikes specifcally. The two things together often leave me wondering. Love to hear that his ideas are not totally off track. Now he can go ahead and I can start cleaning.

Sean
 

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Discussion Starter · #11 ·
Utterly frustrated! We have removed the rotor and replaced it with another one. Cleaned the contacts and used dielectric grease. Had spark for one try and then no spark again. I am about to do one of two drastic things... sell it off or.... even worse... take it to a shop. Either is an admission of failure. I feel at this point that we are actually making things worse.
 

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Discussion Starter · #12 ·
I have swapped them for the ones in my parts bike. The problem is I dont know how to test these, so I dont know if the old or the new ones are any good.

Sean
 

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I'm wonderng if the problem isn't with either the kill switch or ignition switch? Something is interupting electrcal current and from what you describe it just doesn't sound like an alt or cdi issue. Just a thought.
 

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The ignition on that bike is a CDI magneto....It "kills' by grounding out, not by "opening"..... IF the wire that goes to the coil (and splits off to the "kill") is grounding anywhere it will disable the spark...
 
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