Coil question

[scott s]

The hole spacing is the same but the holes in the new coil are slightly smaller so, rather than drill them out, I'll go to the hardware store and get some new screws and acorn nuts and just re-use the stock spacers. Should work just fine.

Curious though: would/could I damage the coil if I were to run a bit through the holes to make them big enough for the stock screws? It's literally like one drill size larger.

 

[Enginedoctor]

the steel pieces protruding through the coil itself are usually several layers sandwiched together. for that reason, it's easy to screw up the very first or very last layer. if you use a good sharp drill bit and the right drill (or better a drill press) and take your time, no, you shouldn't damage anything.

since there's already a hole there, usually metal (steel) will drill fairly easily, with a good bit. getting the pilot done is usually the toughest part, and if you skip that altogether, kiss a few drill bits of the intended size goodbye.

just make sure you back up the metal before you push on it with the drill. maybe a block of wood under it?

 

[scott s]

Okay, I was able to carefully drill out the holes on the new coil and have it mounted up just like the stocker.

I went by my local shop to get a condenser and all they had in 6V was this one from a CB100 or something like that. He said it was a twin, hence the two leads, but that it was 6V.



When I asked about installing it, his instructions were to mount it on the coil in the same place as the original and that would be the ground.
He then said that the two wires from the condenser need + power. I was told to make a splitter from the power wire to the coil and use it to power the condenser. I asked several times for clarification but, being the electrical dummy I am, I'm not sure I understand.
If the condenser is grounded to the coil/bracket/frame and power is going from the main harness to the coil and condenser, how does it get BACK to the coil from the condenser?
Will what he told me work at all? Will this condenser work at all?

He's saying to connect these two wires, power to the coil and the condenser wire, to the wire from the harness that feeds the coil.

 

[theraymondguy]

With coil ignition, not everything happens in a New York Minute. In layman's terms, the positive input from the magneto coil doesn't hit the condenser, then the coil or reverse. It is meant to hit both at the same time. The condenser will 'store' a small current as the voltage is received, the coil will 'charge' on the power received. As the coil 'fires' / discharges, the condenser will 'support' the coil as it 'fires' via the connection your ebay seller is asking to make, elongating the 'firing' time and strengthening the spark generated by the coil at the spark plug.

 

[scott s]

Just to clarify, the condenser came from a local Mom and Pop shop and the mechanic there told me to wire it up as I described.

Sounds like, from what you're telling me, it will work that way?

 

[theraymondguy]

Exactly, it will work just fine. One thing I forgot to mention, the coil charges and condenser stores a small current when the points are closed, the coil discharges when they open.

Ideally your condenser would have the same capacitance value as the stock unit, but realistically it'd have to be a good bit out of range for it to be a problem.

 

[scott s]

Next two dumb questions:

1) On the CL70 blue is ground and black is power, right? So, when I splice the coil and condenser wires together, they need to go to the black wire on the main harness.

2) The 12V coil from eBay came with a spark plug cap. The replacement 6V coil did not. Any reason I can't use the spark plug cap he sent with the 12V coil? If you tell me what to check for, I can Ohm it out for you.

 

[theraymondguy]

Next two dumb questions:

1) On the CL70 blue is ground and black is power, right? So, when I splice the coil and condenser wires together, they need to go to the black wire on the main harness.

2) The 12V coil from eBay came with a spark plug cap. The replacement 6V coil did not. Any reason I can't use the spark plug cap he sent with the 12V coil? If you tell me what to check for, I can Ohm it out for you.

The black wire on your CL harness will be the positive to the coil and condenser. As to which wire is which... I dunno. Hopefully they were marked. One of the two wires will most likely be ground and the other positive, but I can't say that with certainty.

The primary side of the coil will be the issue, it's impedance will dictate whether this coil functions or not. look for 1 - 5 ohms impedance max using a digital multimeter. Tuning the secondary may be of some benefit, ideally from the inside of the spark plug boot to the coil body should be ~13- 15 Kohm on a digital multimeter. If you need to install a boot without a resistor, to get this number, I'd advise doing so. If it's 8 Kohm without the boot (go right to the wire), you can purchase a 5 Kohm NGK boot readily (part # LD 05)
http://www.ebay.ca/itm/Motorcycle-N...ccessories&hash=item35d72f092a&vxp=mtr&_uhb=1 .

Honestly, I think you'd be better off with a 1 wire CT 70 condenser, use the same mounting technique for your condenser.

http://www.ebay.ca/itm/New-Honda-Co...ccessories&hash=item256a9335a2&vxp=mtr&_uhb=1

 

[scott s]

But that just brings more questions...

I'm sorry. Really I am. I just don't understand electrical very much.

If I mount the condenser to the coil, where does the wire on the condenser go? The stock one was soldered to the + (?) side of the coil. I guess I could do, like you said, and splice the condenser wire into the + wire for the coil?

 

[scott s]

Oh, and from what the guy at the shop told me, the coil I have has two + wires since it was for a 2 cylinder bike. They're both the same color, same end on the wire, etc.

 

[Enginedoctor]

those two wires represent the same path to the condenser. one can go to the coil, and the other to the source. having two wires just made it easier to hook to the two coils of the other bike. the ground of the condenser does the work. look at a condenser as a 'high speed' battery that doesn't produce voltage, it just stores a tiny bit for the coil to do it's job.

Also, having the condenser grounded allows it to do it's job. if it weren't, it wouldn't be working on the same circuit as the coil and battery etc. just know that the coil has to be grounded, So does the condenser, And the condenser MUST be hooked to the same circuit that feeds the coil. Doesn't matter 'where' so to speak, just in between the points and the coil. Thats all. Don't try and understand it if you don't think you can, just hook it up and get spark.

 

[theraymondguy]

E.D. is on the money, I wasn't aware the capacitor you have was for a twin. Connect one wire from the condenser to the black from the magneto, the other to the coil and job done. It may not be a long lasting solution, but should get you spark / riding in the interim - possibly for a good length of time.

I would invest some effort in measuring the secondary side of the coil, adding a boot if necessary.

 

[scott s]

It may not be a long lasting solution, but should get you spark / riding in the interim - possibly for a good length of time.

I would invest some effort in measuring the secondary side of the coil, adding a boot if necessary.

Yes. the condenser is for a twin. It's all the Mom 'n' Pop store had in 6V and it was free, so....

Why do you say temporary?

And I'll measure the coil, but can you give me instructions in "Electrics for Dummies" language?

 

[Enginedoctor]

okay put your meter in 'ohms' mode. looks like the omega symbol. You take one lead and put it to the small wire going to the coil. then take the other lead and put it to the thick wire coming from the coil. (where the spark plug cap would go.) this would measure the secondary side of the coil. refer back to earlier posts for 'good' measurements

 

[scott s]

On the 200k ohm scale, I get 16.4 through the coil. I have to set it to the 200 scale and I get a very low reading through the new cap.... ~0.1 or 0.2. Kind of hard to get a stable reading on it.

For comparison, the old coil, with cap installed, reads 23.6 on the 200k scale. The new coil, I checked without the cap installed.

 

[scott s]

And if those numbers look OK, I tried to follow your advice and plugged the condenser into the coil....nice, tight fit on the plugs.



And I soldered/shrink wrapped a genuine Honda bullet fitting from my box 'o' stuff to the other wire on the condenser. That bullet fits the female end on the wiring harness very well.



That only leaves the stock blue ground wires. But, if I understand correctly, the coil and condenser will be grounded to the frame. If needed, should I put a ground wire under one of the mounting studs and run it up to the blue ground wire on the harness? Just to be safe?

If you guys give me the thumbs up on this, I can install the coil and get the motor back in the frame.

 

[scott s]

I don't think this is right....

I got a manual that has a wiring schematic I can actually read. The black is power to the coil. The blue is NOT a negative or a ground, but is coming from the points.

Now that I've spliced the wires together, have I ruined this condenser set up?

I need to get the condenser to the blue wire coming from the points AND have the black wire going to the coil.
I think....

 

[scott s]

At this point, I'm willing to use the old coil IF those numbers look good.

The old coil, with cap installed, reads 23.6 on the 200k scale Is this acceptable?

 

[scott s]

I removed the cap and trimmed 1/4" off the oil wire. Re-measured and got 11.8 on the 200K scale. The cap measured 10.3.
Sound OK?

 

[Enginedoctor]

The wire to the condenser can't be both power and ground. It won't work if it is. You can re splice if you need to.