Spark Advance

[grubsie]

Finally getting back to working on my 63 CA95. Been sidetracked with business closing, weddings etc. It has been so long that I can't remember the correct way for the spark advance lobe to fit. I know that it can either be correct or 180 degrees out. I want to make sure I do it right the first time. If I remember correctly, it should be set to open the points just before TDC of compression stroke of the right side cylinder. (Clutch Side). Any help would be appreciated.

[Spokes]

I will answer your question tomorrow night. I am installing a known correct ignition set up on my CA95 project bike and will take a pic to post.

[VegeKev]

Hey Grubsie,

Recently went through exactly the same scenario....I ended up having it back to front as I thought that as the 'F' mark lined up then power would be cut to the coil, allowing a spark to be generated....WRONG! (ha...50/50 chance and blew it )
So now I know that (with your trusty 6V bulb and battery connected up) you want the bulb to LIGHT as the 'F' mark lines up with the timing mark.

Kev.

[Spokes]

Here is the pic I promised. Hope it helps.

[grubsie]

Thanks for the picture Spokes. I am still in a fog here with the electrics. My understanding is that when the contacts of points open, a pulse is sent to the coil causing the spark plugs to spark. That being said, having removed the spark advance lobe from its base plate and spring unit and not remembering which way it was... does it matter which way is is put back on as long as the the points open (or close) when the F mark lines up with timing mark? The manual I have says something about the points should closed at this timing mark. I am also assuming that I do not have to be concerned which cylinder is on the compression stroke at this timing point because both plugs fire at the same time anyway so at firing, one or the other will be on its compression stroke.

[grubsie]

Thanks for the picture Spokes. I am still in a fog here with the electrics. My understanding is that when the contacts of points open, a pulse is sent to the coil causing the spark plugs to spark. That being said, having removed the spark advance lobe from its base plate and spring unit and not remembering which way it was... does it matter which way is is put back on as long as the the points open (or close) when the F mark lines up with timing mark? The manual I have says something about the points should closed at this timing mark. I am also assuming that I do not have to be concerned which cylinder is on the compression stroke at this timing point because both plugs fire at the same time anyway so at firing, one or the other will be on its compression stroke.

[rum-rum]

i did the same thing putting the spark advance lob on backwards 50 50 chance and i did it wrong the first time too

[Larzfromarz]

Actually while the points are closed a magnetic field is being created in the coil. When the points open the magnetic field in primary coil collapses and induces and current in the secondary coil (remember its really a transformer) that creates the spark at the plug. Honestly with a 50/50 chance, if it won't start (and everything else is good), flip the thing and see if it will.


So for general knowledge- When a coil "shorts" internally is is usually due to overheating and the varnish that insulates the wire melts and internal contact is made either in the primary or secondary winding itself (reducing the ability to build the proper magnetic field) or the contact is between the primary and secondary coils thus completely defeating and chance of a current being induced into the secondary resulting in either very poor or no spark. The coil, thru magnetic induction (the electrical theory behind transformers) takes our battery voltage that we supply to the system and transforms or "steps up" the voltage to around 20-30,000 volts for spark at the plug.
Transformers can step up voltage or step down voltage. An example of a step down voltage is the little "wall wart" or transformer that we charge all of our gadgets on (cell phones etc). Takes "wall voltage" 110v AC approx and transforms, steps down the voltage to something you can use (6-12 vdc). This is why they say not to leave these things plugged in. They use energy all of the time and dissipate that energy as heat or dollars into the air.

[Colorado66]

I'm trying to take any guessing out on which way the lobe fits as I'm assembling a new engine.
Could someone please confirm if the points are open (gap of 0.03-0.4MM) when the timing marks are showing?


Or do I have this 180 degrees off?

Thank you

[VegeKev]

As the "F" lines up with the pointer, you want the points to close
Kev.

[Sam Green]

To start with, make sure your points are clean and not pitted, also make sure that the heel of the points (the part that rubs on the cam) is not worn.
If in doubt, buy new points, they don't cost the earth and can save a lot of time if you are unsure if the heel is worn.
Remove tappet covers GENERATOR side.
Rotate the motor anti clock wise.
Just before the F starts to line up, both tappets should be loose.
This tells you that the cylinder nearest to you (points side) is on the compression stroke and the piston is nearing TDC (top dead center).
As the F comes into line with the pointer, the points should start to OPEN.
If you put a battery and bulb across the points, the bulb should light up as the F aligns with the pointer, this is assuming that the points gap is set correctly and the points back plate is in the correct position.
Some might think that because both cylinders fire at the same time, it shouldn't matter if the points cam is 180 degrees out.
The thing to remember here is that the crankshaft turns twice to the camshafts once and you'll end up getting sparks at the plugs when the valves are out of phase with the timing.

Have fun.

Sam.

[Colorado66]

As the "F" lines up with the pointer, you want the points to close

As the F comes into line with the pointer, the points should start to OPEN.

I'm sorry but am confused.

should there be a gap (open) as shown in my picture when the pointer is close to the "F"?
Or shouldn't there be a gap (closed) ?

Sorry for the newbie questions and thank you

[Larzfromarz]

The points should "OPEN" at 'F' or "Fire" to collapse the magnetic filed in the coil creating the spark. The magnetic field is building (dwell) while the points are closed.
Kev is in the southern hemisphere so we have to translate....
L

[Sam Green]

Thanks Larry but I didn't want to say that.
Kev is a real nice guy and WE have a lot to answer for.
I don't think that we realised that we sent you to a world where the bath water goes down the plug hole in the opposite direction and Christmas falls in the middle of summer, that the stars revolve around the heavens in the opposite direction and we sent all our best CRICKETERS to play for Australia.
Oh and I forgot, you owe me 38,000 Aus $ for the part I sent you for your Honda.

Don't worry Kev, I've done it myself and I don't have your excuse, but I am very old and that's my excuse.

Sam.

[Larzfromarz]

Plus 1 on Kev! Wish he was/I was closer.
The internet is great but would it be awesome to get everyone together in one place, one time? Cool fantasy....