Topic: Spark, Fuel, Compression. Still not running...

[Slayer]

Well I have finally made it up to the big three. In my unexperienced opinion it is the points. I have gapped them and cleaned the points as good as it is going to get. They do not spark when I am trying to start it. I measured 6 ohms on the 1-4 mark, 5.5 ohms on 1/4 turn, 5.5 ohms on 1/2 turn, .2 ohms on 3/4 turns. I have a feeling it should have zero continuity when not at top dead center. The only other potential problem is the the plate has bad threads for the yellow wire and I can't tighten it as well as it should. I have a spare plate so I am going to swap them out and re adjust gap and try the static timing again. Am I on the right track or chasing ghosts?

[fuzzybutt]

have you tried reversing the wires to the points, just in case you reversed them

[Slayer]

Traced the wiring and everything is all lined up. I changed points plates and what a mess I have made. It felt pretty tight and would not slide back and forth very well but I tried it anyway. When I cranked it the whole plate was wobbling around and metal shavings were falling out  I took off the plate and saw the wear on the plate and noticed on one of the spark advance spring posts was broken. I swear it feels like I spend more time fixing my F ups than the ones that the bike came with. Time to bust out the JB weld and a little Dead Kennedys.

Oh one other thing I noticed differently. The plate was sparking agianst the engine. Is this good or bad? Why?

[Hush]

You def should not get sparking from the points plate to the engine!
Sounds like your power wire to the points is earthing somewhere, that will act just like a kill switch but will incur damage to battery/points/coils/fuses pretty quickly if I'm right.
Double check your points, esp the area where the power wire attaches to them, make sure it is not coming into contact with anything else, you maybe onto the reason the bike wont start here so recheck and good luck.

[TwoTired]

You def should not get sparking from the points plate to the engine!

If it is loose and the power is on, why not?

The points complete an electrical circuit to battery NEG terminal via the frame and engine castings.  The points plate mounts on that casting.  Loosen the plate and you have added another contact point/gap.  When it breaks that connection the power to the coils is broken (assuming either point set is closed).  When the coil's magnetic field collapses, it makes high voltage in both the primary and secondary windings.  This backwards electromotive force can rise to a couple hundred volts, and arc across the gaps between plate and engine case.

The points are normally closed through 195 degrees of crankshaft rotation.  With the stock point cam, this is achieved when the widest open gap is between .012 to .016 inch.  While the points are closed during crank rotation, the coils build a charge.  When the point cam rotates to force the points open, the coil power dumps energy into the spark plugs forcing an arc across the gaps.

An ohms reading uses the meter's own power passed through the probe tips.  It knows what is sent and measures what it gets back on the other probe.  The difference reading is how it interprets the circuit resistance being tested.  An ohms reading by itself is meaningless unless the circuit is also known between the probe tips and no external power is being driven into the circuit.  This means we must know where you put the freaking probe tips during the measurement for any reading make an iota of sense.

I have to wonder why points setup is such a mystery?  It is described accurately in the both the owners and Honda shop manuals.  I think there is a description in the FAQ as well. 

 


Maybe I should just stay away from these threads.

[Slayer]

I have gone over the FAQ time and time again. I have been reading the maintenance manual every step of the way. The manual says you can adjust timing with an ohmmeter (engine off) by taking one probe tip to ground and the other probe tip to the blue wire for 1-4.  I guess it would be a better way to check via voltage since I have spark now. It is such a mystery to me because it seems like it is working but it is not. I have never worked with anything electrical until I started digging into this bike. Sorry for the little question marks over your head I have them too.

[TwoTired]

What manual says to use an ohmmeter?

[Slayer]

Clymer page 54, chapter three periodic maintenance and tune up, Ignition Timing, Static Method. The first paragraph: The static method requires something that can signal when an electronic circuit is opened or closed. This can be a buzz box (ignition on), an ohmmeter (ignition off) or a continuity light (ignition on). This later method, often called a timing light, is the least expensive. It is available for under $2 at parts stores.

The manual says to put the probe tips to the blue wire and ground the other wire. Thats what I did.

[TwoTired]

If you must use an ohmmeter, you look for the transition point of zero ohms to higher reading.  Tthat is when the points open and you are reading the resistance the the other coil through it's closed points.

Or you put some thin insulative material between the points you aren't adjusting, and when the meter goes from Zero to infinity, that tells you when the points open.


Have you removed the spark advancer under the points plate?  It can be reinstalled 180 out phase, which would make spark occur at the wrong time.  Find actual TDC of #1 or #4 piston.  Do the timing marks line up?

[Duke McDukiedook]

A dwell meter for points would be a more accurte tool than an ohmmeter.
But, that means more money. If you got a tachometer/dwell meter you would have one very useful tool for your motorcycle.

[Slayer]

If you must use an ohmmeter, you look for the transition point of zero ohms to higher reading.  Tthat is when the points open and you are reading the resistance the the other coil through it's closed points.

So when I measured: 6 ohms on the 1-4 mark, 5.5 ohms on 1/4 turn, 5.5 ohms on 1/2 turn, .2 ohms on 3/4 turns, it should have been 0 until TDC right? That is where I started to get confused.

Have you removed the spark advancer under the points plate?  It can be reinstalled 180 out phase, which would make spark occur at the wrong time.

I did remove it when the springs were stuck. There is only one pin, how do you put it in 180 out of phase?

Find actual TDC of #1 or #4 piston.  Do the timing marks line up?

I don't think so. The cam starts to open the points slightly after the timing mark.

A dwell meter for points would be a more accurte tool than an ohmmeter.
But, that means more money. If you got a tachometer/dwell meter you would have one very useful tool for your motorcycle.

I am pretty broke but once I have some cash for tools that is first on my list. Hey at least it is better than giving up and getting a Dyna right?

[Spanner 1]

Bro Slayer, all you want to know from your ohm meter is when it goes from a reading to no reading....that is all, nothing else..! The exact point where the meter drops to no reading is where you get your spark...so, you need to slide your points plate up or down to make this happen exactly at the F ( fire ) mark...repeat on other set of points and your done  !
Rotate crank slowly to find the spot where the points open ....meter goes to no reading, rotate 180 deg. to other F mark to set the other point.....

[TwoTired]

If you must use an ohmmeter, you look for the transition point of zero ohms to higher reading.  Tthat is when the points open and you are reading the resistance the the other coil through it's closed points.

So when I measured: 6 ohms on the 1-4 mark, 5.5 ohms on 1/4 turn, 5.5 ohms on 1/2 turn, .2 ohms on 3/4 turns, it should have been 0 until TDC right? That is where I started to get confused.

You don't need to know the measurement number, you need to know when the reading changes state as you rotate the crank.  Before the 1.4 mark it should read zero, when the mark is aligned, the reading should go higher.  You rotate the main plate to adjust this.

Have you removed the spark advancer under the points plate?  It can be reinstalled 180 out phase, which would make spark occur at the wrong time.

I did remove it when the springs were stuck. There is only one pin, how do you put it in 180 out of phase?

If you took the point cam off the advancer assembly, you can put it back on with the cam 180 degrees off.  If you did that, you won't get the points to open on the timing mark.

You don't need a dwell meter to get the engine to run.  I usually time with a 12 v instrument lamp with two wires and alligator clips on it.

[Slayer]

Since I have voltage I did the dynamic timing with the ignition on. I set up a voltmeter positive probe to the blue coil wire for 1-4 and the negative to ground. I also set the #1 coil cable on the engine block with a spark plug in it to actually see the spark just to make sure. It turns out that I got spark right on the firing line (F 1-4). The problem is that coils 1-4 spark at the firing line (F 2-3) also, and vice versa with the other coil connected to yellow. The voltmeter measured 10.5V about 180 degrees after spark and 9.5V about 180 degrees before the spark. When it sparks it goes from 9.5V - 10.5V.

It looks like both electric circuits are the same. Both points open and close opposite of each other and the blue points spark, not the yellow.

[TwoTired]

In a working system, the voltmeter has it's probes placed, electrically speaking, on either side of the point contacts.
When the points contacts are closed, the voltage potential (which is what the voltmeter is registering) should be zero volts, just like if you placed the probe tips together.
When the points open, the voltage rises to a value that is seen on the Black/White wire feeding the coils (near the spine of the bike, where ever that is).  This voltage transition point should occur when the crank is rotated (clockwise on the timing plate) and the 1.4 F mark aligns with notch on the engine case.

The same arrangement occurs with the 2.3 mark when probing across the 2.3 point set.

Some things that can go wrong:
The point contact surfaces may have material on them the prevents their electrical closure.  (This is supposed to coincide with their mechanical closure)
There can be wire connection issues (opens, groundings, shortings) that can occur between coil and points connection.

You can use the voltmeter to verify that the Blue and Yellow wires do NOT carry the same signal.  If they do, it is unlikely that the points or timing is the culprit, and you should look for blue and yellow wire routing issues.

To save your battery, you might consider removing your headlight fuse, while probing about with a voltmeter.

Cheers,

[Slayer]

I will do the same test with the probe on the side of the point contact. Let me make sure I have this right. Probe to wire contact on the points, right? Other probe to ground? It seems like I should test the black and white connection since that is the voltage that supplies the coils.

I think the points contacts are fairly new and there is no wear or misalignment. I made sure to rub a clean business card on both surface points on the points before testing. Since I am new to electrical wiring I am pretty sure it is something I did wrong, but there is not much wiring involved. The only thing I was kinda unsure about was when I connected the blue wire and ground wire to the points. They are separated by a washer which would make contact between the two right? Is this correct? Sorry if this is frustrating dealing with the ignorant. I learn better looking at a working model than learn as I troubleshoot. Thanks again TT

Thanks for the headlight tip, it will save me some charging time for sure

[IHWillys]

Caveat here, I just got my first CB a few weeks ago so my Honda CB expereince is nill.

However, I've been dealing with points for a few years(since about 1980).  On bikes I may set timing using various methods but one thing in common with static setting with a points system is I disconnect the points leads and put an ohmmeter across the points.  Put the meter next to whatever crank reference I'm utilizing and it's a very simple task to see both the indicator and the meter to see exactly when the points open and close via the change from infinite resistance(open points) to 0(closed points).  The spark occurs when the points open.

Key point using this method is one isolates the points by disconnecting the wires.

May not be the best and doesn't help with wiring issues but it does settle the timing of the points open/close and their continuity.  I've had points that looked perfectly good and clean on the contacts but still would not "close".

Ken

[Slayer]

Caveat here, I just got my first CB a few weeks ago so my Honda CB expereince is nill.

However, I've been dealing with points for a few years(since about 1980).  On bikes I may set timing using various methods but one thing in common with static setting with a points system is I disconnect the points leads and put an ohmmeter across the points.  Put the meter next to whatever crank reference I'm utilizing and it's a very simple task to see both the indicator and the meter to see exactly when the points open and close via the change from infinite resistance(open points) to 0(closed points).  The spark occurs when the points open.

Key point using this method is one isolates the points by disconnecting the wires.

May not be the best and doesn't help with wiring issues but it does settle the timing of the points open/close and their continuity.  I've had points that looked perfectly good and clean on the contacts but still would not "close".

Ken

So basically do the same ohmmeter test as the first except take the blue wire out and replace with the probe?

[TwoTired]

I will do the same test with the probe on the side of the point contact. Let me make sure I have this right. Probe to wire contact on the points, right? Other probe to ground? It seems like I should test the black and white connection since that is the voltage that supplies the coils.

If you want.  But, voltage can only be measured at open points if power is going through the coil.  So, by inference, power must be getting to the coils if you can measure it at the points.

I think the points contacts are fairly new and there is no wear or misalignment. I made sure to rub a clean business card on both surface points on the points before testing.

You're probably ok. But, FYI the metal can make a transparent, non-conductive coating that can fool the eye.  Electrons know the difference, though.

Since I am new to electrical wiring I am pretty sure it is something I did wrong, but there is not much wiring involved. The only thing I was kinda unsure about was when I connected the blue wire and ground wire to the points. They are separated by a washer which would make contact between the two right? Is this correct? Sorry if this is frustrating dealing with the ignorant.

The ground is the mounting plate itself.  The "ground" wire you refer to, is actually the connection to the condenser, I assume.  It better not be ground.  The assembly order on the point's wire post, is both the wires first, then flat washer, then lock washer then nut.  As long as the washers are electrically conductive, the order won't matter electrically.  But, for mechanical retention over time, the order is significant.

Don't worry, ignorance is correctable.  We've all had it about something at one (or more) times in lives.  Hopefully, the condition is curable with enough perseverance.
Wishing to or insisting on remaining ignorant, is where it gets frustrating.  Dealing with invisible stuff like electricity, is mostly a mental exercise, even though it takes physical things for it go where where needed.  Sometimes, electron herding is more like chicken or cat herding.  But, even they are predictable if you only give them one way to go.  It's the same with wires and electricity.

Cheers,

Cheers,

[Slayer]

Yesterday evening I did some tests to help narrow down the problem. First I did the points isolation test provided by IHWillys. 1.4 and 2.3 both break continuity at the F line. So the actual points are good.

Next I tested the 1.4 points under power. I put the positive probe from the multimeter on the blue wire where it connects to the points, and the negative probe grounded to the plate. I started with 0V and turned the crank clockwise until I got a reading. I read 11.11V at the "1" mark on the plate that shows 1-4. Voltage broke at the "T" on 2.3 side. Good

2.3 side was next. I got 11.01V starting at the "2" on the 2-3 mark. Voltage broke at the "T" on 1.4 side. Good.

There was a little bit of voltage overlap from the 1.4 and 2.3 sides that occurred but that should be normal since I read somewhere that it should be feeding voltage 190 degrees of the cycle. The overlap starts at the 1.4 "F" mark and and stops right after the "T" at 1.4

So it looks like the tests show that the points system is operating correctly. The only abnormalities that I am aware of is the double sparking. I would guess I have to check my wiring. Is there a good systematic way of going through this?

[TwoTired]

Well, that's a good progress report.

Honda says the point "dwell" is 195 degrees of crankshaft rotation.  This is the number of degrees that the point contacts are closed, as determined by the point cam profile and the gap setting.

"Dwell" is also the charge duration of the coils, where the coils receive the energy they need to provide spark.

It is normal for the coils to make spark both when the points close and when they open.  If the coils build charge fast enough, they can cause an output spark potential.  As this is at the bottom of the piston stroke, such spark, while unnecessary, is not harmful.  The charging spike is not normally very powerful, or reliable for combustion purposes in the SOHC4.  But, where you really need the spark, is when the points open, and that is why there is a dwell spec.  The points open caused spark should happen when the cylinder has an fuel air mixture charge, initiating combustion.

If your spark plugs are indeed throwing an arc across the gap at the right time, it sounds as though your ignition system is ready to run.  If you spin the engine with choke on, do the spark plugs get wet with fuel?

Cheers,

[Slayer]

Oh that is a great question. I am curious to find out since the only thing I know for sure about the carbs are that when I open the drain plugs they all drain fine. I guess all that means is that the carbs are getting fuel. This test would prove if the fuel gets to the cylinder. Damn I wish I was home.

[Slayer]

Choked the carbs and cranked it over. No fuel on the spark plugs. Tried it twice for the warm fuzzy feeling. So it looks like I have my weekend planned out. I am going to do some research before I start ripping things off. Clymer, FAQ, and previous threads here I come!