ISO 2 stroke ignition guru
 

Lots of talent here, so I'll give this a try.

1978 Honda Hobbit PA50II
magneto ignition with points, coil with external condenser
Problem: no spark

If anyone wants to play along, I'll post all my diagnostic info on here.

Any takers?

Go......I'll play.

Bring it on!

It's been 2 hours.... you got a question? :Unknown:

Maybe he checked the kill switch or the key :bigthink:

If he has a problem with a 3 stoke sinusoidal encapsulation valve causing the bi-directional sleeve valve to convolute the electro magnetic field to reverse polarity he can try inversing the vari-valve accumulator ball valve to restore retro firing of the after burner causing the directional reversing of the power piston.
That should rectify the platinum ferro deposit transfer.:beerchug:

Looks like maybe his interweb went down too.

Looks like some interest. Nice day out, yard work to be done.
I have a lot of info to post; might take me the rest of the afternoon to get it on here.
Start off with photos of the parts.
http://www.onlycubcadets.net/forum/p...pictureid=6663
http://www.onlycubcadets.net/forum/p...pictureid=6664
http://www.onlycubcadets.net/forum/p...pictureid=6665

How about start with what you know/don't know. We all know what the parts look like....:beerchug:

OK. It will take a couple posts.
Stator and points:
Points are new Honda OEM, set at 0.014"
Resistance measurements for stator, measured with points open.
red-green 2.1 ohms
red-yellow 2.5 ohms
green-yellow 1.4 ohms
black/green 1.9 ohms
green-frame 0.2 ohms

Coil and condenser. New aftermarket.
Tested anyway. Condenser will take a charge and hold it.

Connected black wire from stator to coil yellow wire. Grounded coil with jumper wire to engine case.
Flywheel installed. Spark tester installed between high tension lead and spark plug installed in head.
Spun motor with electric drill.
No spark.

Finished with test info.

File points.
Check for no short to ground on kill wire. (Disconnect it)

Are the points getting any voltage? Check with test light while spinning engine.

Points are lightly filed with a points file and cleaned with rubbing alcohol.
Motor is on test stand, not installed in frame. There are no wires connected except those mentioned.
Points getting voltage?? There is no battery. This is a moped. Pedal it a couple revolutions and the motor is supposed to start.
The points are behind the flywheel. I don't see how to connect a test light behind the flywheel and spin the engine.
Your help and interest is appreciated.

Coil test that I used:
http://www.onlycubcadets.net/forum/p...pictureid=6666

Ok. Most likely making contact then.


Good deal. Not likely a short then. Still possible.... but less likely.


The points still have to get power. That's what the stator does. It makes electricity when you spin the motor, whether that is via your drill, or from the pedals. The points have to get power or no sparky, sparky.



The coil is outside the the engine, yes? Connect a test light to the wire that from the points to the coil. Disconnect the wire at the coil, and insert a test light. It should blink when you spin the engine. If not, your not getting power to the points, or they are not opening/closing.

I think I have a book on that engine... I'll go dig around and look at it real quick to refresh my memory. It's been a while since I played with an old Honda motor..

Just a guess here, is the movable point of the set inadvertently grounded? (chaffed wire or similar)
is the coil that makes power for the ignition system ok? (not shorted or open) so it is able to make power to operate the ignition system/high voltage coil.
From the pix, it looks like you have 2 lighting coils as well as a coil for ign system.
Those handlebar switches/controls are known for problems, as John suggested.
Thinking the switch interrupts the power generated for the ign system rather than use a "kill" wire to ground a "magneto"
do you have a wiring diagram to support your troubleshooting endeavor?
Never worked on that particular moped, but on similar small honda 60-90 CC engines, and that was how they worked
Edit:
John & I are thinking/posting about the same time, along the same lines AGAIN, HA,LOL

Thought of something else. IIRC, that ignition coil bolts to the frame of the cycle. If you have the engine out of the frame and on a bench, did you bolt the coil to the engine? I believe that it has to be grounded.

"The coil is outside the the engine, yes? Connect a test light to the wire that from the points to the coil. Disconnect the wire at the coil, and insert a test light. It should blink when you spin the engine. If not, your not getting power to the points, or they are not opening/closing. "

There are a couple windows in the flywheel. Rotating the engine by hand I can see the points open and close.

Coil is outside the engine. I connected a 6V test light between the black wire from the stator and the yellow wire on the coil. Spun the motor. Nothing.

Connected a DVM in place of the test light, set on VAC. Got 8.9 mV at max drill speed, spark plug removed from head. Not sure if that's enough to charge the condenser.

I have a jumper wire from the coil mounting bolt hole to the engine case for a ground.

Info taken from mopedarmy.com relating to stator testing:
http://www.onlycubcadets.net/forum/p...pictureid=6667

Wiring diagram. Sorry it's not the best image. It's available on a Google search.
[/I]
http://www.onlycubcadets.net/forum/p...pictureid=6668

The movable contact on the point set is not grounded. Points closed there is 0.2 ohm resistance. Points open there is no continuity.
The coil checks out. The condenser builds a charge.
Yes, two lighting coils. The red wire and the yellow wires from the stator.
Thanks for the questions.

I'm sorry. I'm not thinking this through. I gave bad info. Let's start over.

First off, you don't "charge" a condenser. It just absorbs the voltage spike that occurs when the points break.

Points don't have power going to them (per se). They open and close the ground connection to charge the coil. I told you wrong on how to test them.

Questions:
How many wires running to the coil, what color, and where do the go? If I'm not mistaken, should be 2. One from the stator, and one that goes to the points. The condenser should also attach to the point wire.

This motor doesn't use a rectifier correct? Wire runs straight from the stator to the coil?

I'll be back at the pc soon. I'll look over those pics.....

"Charging" a condenser.
This is the procedure I used to check out the condenser
I have the same DVM.
https://www.youtube.com/watch?v=FxD1OpPQaS0

"Questions:
How many wires running to the coil, what color, and where do the go? If I'm not mistaken, should be 2. One from the stator, and one that goes to the points. The condenser should also attach to the point wire.

This motor doesn't use a rectifier correct? Wire runs straight from the stator to the coil?"

There is one wire on the coil, yellow in earlier photo.
4 wires from stator. red and yellow are for lighting, black connects to yellow coil wire, green is ground.
No rectifier in the wire from the stator to the coil. There is a rectifier/regulator in the lighting circuit to keep from over-voltage the 6V light bulbs.

Sorry, I don't know how to separate questions and answers as you do.

I've got to entertain some guests for a while. I'll be back later with some direction...... hopefully. :biggrin2:

Click the multi quote icon (its the one to the right of the quote icon at the bottom right of each post, I think (occasionally)) and then edit the quote and add your response.

Thanks twoton!

I'm probably done for the night also.

Soooo.... this ignition system is like nothing I've ever seen on a Honda. Now, that said, I've never played with the mo-peds.

This is an A/C ignition system. It functions much differently that any other because of using A/C current.

The wire that comes to the coil from the stator is also the signal wire from the points. The points simply ground out the wire when they close, and when open, it lets the current go to the coil. (Electricity always follows the path of least resistance.) I cannot find any info on the voltage that the A/C generator puts out, but can tell you that you will not have any luck testing with a test light. My suggestion is finding out how much A/C voltage that is supplied to the coil for spark, setting the points open all the way so that they cannot close, and spin the engine and see if it is making power. Then test further from there. My guess at this point is that the winding responsible for power to the coil in the stator is bad/open. There are 3 windings in the stator. 1 for the ignition, and 2 for all other power sources. Depending on year, the voltage fed to the coil may or may not be direct fed. On some models it feeds through a silicone rectifier before going to the coil. Near as I can tell, this is just to feed extra voltage to the ignition coil, from the other two stator windings, during low voltage situations. (I.E. starting and sitting idling with all the lights on.)

I suggest you find a book or PDF of how to do a component test. I found a PDF of the supposed Honda manual for that machine, but outside of tear-down and assembly, it was vague at best.

Holler at me if I can help.

The early 2 smoke single Yamaha's '68-'72 used an AC system like that.
they put out 135-150 V. to supply the ign system,-- if that helps.
look closely @ your source coil for the Ign.

I do not understand. To me, the schematic clearly shows the wire from the stator intersecting the silicon rectifier on the way to coil. Care to enlighten me? There's Black/Yellow wire leading to rectifier and from rectifier it's Black/White wire that loops around the stator (in sketch) to the coil.

I thought this images without the colorful gobbygook wires might be easier to see here. Maybe/maybe not:

Attachment 70288

In the Honda manual, there are about 25 different diagrams. Depending on what year, or model there are different diagrams. His cycle may or may not have the rectifier. Also, if you look, the ign coil is not fed off the output of the rectifier. It is fed off of one side, the voltage of that side does not go through the rectifier, so it would still be A/C voltage.

"My guess at this point is that the winding responsible for power to the coil in the stator is bad/open."

I agree with this.
Since new stators are NLA and used ones on eBay are outrageously priced, without a guarantee, I'm going to convert to a CDI ignition.

Thanks to all for your time and effort.

I think you would be ok with a AC brand spark plug. :biggrin2:
Sorry couldn't resist that one

Might not be too hard to use your points as a trigger, and use power from the lighting source coil (s)? to power your existing high voltage spark coil.
---or even throw in a small cigarette package size 6V. battery.
off the top of my head that seems possible.
I've done similar.
But before we condemn the ign source coil, lets see if we can do a little testing of it, gotta be a simple way to check if it has any output and/or if it is open/shorted.
I'm sorry, but I cannot get the wiring diagram on here readable or the ones on the 'net either.
I'm sure it is my lack of computer expertise.
When I enlarge them, they get as fuzzy as long haired kitten.

OK Jonathan, Thanks for the education. I was having trouble seeing why is there a rectifier between the AC alternator and the AC coil. Hey, you gotta pepper the know it all with questions to get answers.:beerchug:

OK Jonathan, Thanks for the education. I was having trouble seeing why is there a rectifier between the AC alternator and the AC coil. Hey, you gotta pepper the knowledgeable mechanic with questions to get answers.:beerchug: