Topic: Wiring Issue?

[Paul E.]

I've been chasing some electrical gremlins and think I might have found them, but i'm not sure what to do about it just yet.  I noticed that when I hooked my voltmeter up to my points it wasn't displaying ~12v's like it is supposed to, but rather ~9.5 volts.  I went up to my non stock coils, the PO put on coils from a Honda Goldwing, and much to my interest found these values.

Left coil: B/W wire = 9.58 v (slowly increasing)
             Yellow wire = 0.97 v (slowly decreasing)
Right coil: B/W wire = 9.67 v steady
                Blue wire = 9.67 v steady

I unhooked the yellow wire and the remaining wires all jumped to 12v!  The 1-4 points also registered 12v.

Just for fun, i unhooked the blue wire, rehooked the yellow wire and the voltages remained the same as when I first checked them. 

Any ideas on what makes the voltage drop when the yellow wire is connected and how it might be fixed?  Perhaps this is indicative that the yellow wire is grounding out on it's path to the points?  But if that was the case wouldn't it register as 0 v instead of 0.99 volts.... 

[Spanner 1]

Your readings are both low and high!.... First off, any testing like this must be done with a fully charged battery ( needs to read 12.6v after charging and a 1 hr. rest ). Most of our bikes run the headlight as soon as the ign. is turned ''on' which over several minutes will cause the battery voltage to decrease vs. time left 'on' , so really need to pull the headlight fuse to remove that 50 w load. When 1-4 point set is open ( no connection to ground ) then the blue wire should read close to the battery voltage ( only with a known good, charged one ). When the cam is turned to close 1-4 points then the voltage on the blue wire should read zero.... if anything above 0 and you are sure the point faces are mated then the points are dirty  .......  same for 2-3 points ; open = battery voltage ( close enough ) and closed = zero volts.
FYI... the points stay closed for  about 95 degrees ( out of the 360 deg. of a full rotation ) to allow the coils to energize and it's when the points open ( separate ) then the sudden drop of energy in the coil primary induces a high-tension voltage in the coil secondary = spark. That's why you time your bike for the points to open @ the 'F'(fire) mark 
One more thing.. ... if you have cleaned the points really well and you are sure they are closing good and you can still detect a voltage on the blue and yellow  wires then your main frame/engine ground is suspect... that's where the battery -(Neg. ) wire connects at the engine mount bolt.... Ever cleaned that up ?

[Paul E.]

Thanks Spanner 1, what you're saying makes sense.  That's kinda what I was thinking was going on with the difference in voltages between the yellow and blue wire depending on what stage the points were in (open or closed). 

The battery i'm using shows 12.76 volts with everything turned off (and a 1 hr rest). I went ahead and disconnected the whole headlight.  I did not disconnect the headlight fuse but will be sure to do that as well to decrease any potential drain!

Since I was only getting 9.67 volts to the points I figured it would be a good idea to move up the wiring until I was back into the 12 v range.  Opening up my Clymer to the wiring diagram I traced the path of the B/W wire and saw that it joins the killswitch.  Well what do you know, just yesterday I worked through Soh Ron's right hand switch rebuild guide and was pretty familiar with the B/W wire's path in the killswitch due to Soh Ron's excellent walkthrough.   

So I disconnected the B/W bullet connection and checked my voltage out of the killswiitch: 12.34 v!  Looks like the switch is working fine.  Reconnecting the B/W wire I went to the connection a couple of inches in front of the coils and got the reading of 9.67 volts.  It would seem that somewhere between the bullet connection in the headlight bucket and the connection right in front of the coils i'm losing voltage.  Everything is all wrapped up in the main harness so I can't see if there are any splices or connections but I think I may have to unwrap the harness and start looking...

Today I cleaned the battery ground and then every connection I could get my hands on in the electrical panel.  I brushed the spade terminals with a wire brush and shot some contact cleaner in there as well and made sure to clean off the voltage regulator and starter solenoid as well.  Everything is looking nice and shiny! 

[Don R]

If you follow the points wires from the points toward the battery area there are bullet connectors around the airbox area. Did you check them?

[Paul E.]

If you follow the points wires from the points toward the battery area there are bullet connectors around the airbox area. Did you check them?

Don R – the bullet connectors (yellow and blue) around the airbox area show 12.23 volts.  Additionally the connections on the coils now read correctly with the blue and yellow wires reading close to the battery voltage when open and close to 0 when closed.  Looks like the voltage issue is being caused by something within the points assembly.

The points are new TEC that I picked up from a dealer about a month ago.  I would think that since they came from the dealer they would be OK.  Could the symptoms I’m seeing be the result of a bad condenser?

[Spanner 1]

Do you get spark now ? Does the bike run ?..... and yes, could be a bad condenser.

[Don R]

I don't know, but I've heard of problems with cheap points. Not sure if that is the case here. Look closely at the springs to see if one is contacting anything on the plate. I had that happen once on a car. If I was close I'd tell you to come get a used Honda points plate to try.
 I was told if a condenser goes bad it will make the spark arc across the points and be easy to see. Hope that helps.

[Spanner 1]

Also, what is the point gap? and how did you set it por favor.

[TwoTired]

Take a look at the electrical diagram.  The coils are fed from a common point.  And we'll assume 12.5V exists there with no load (both points open).

Goldwing coils have something like 2.5 ohm primaries.  As the primary is just a length of wire, they will distribute that 12.5V at full value when no current is flowing.  Any wire or conductor path will distribute voltage in full (compared to source) when no current is flowing. 

If either coil is passing current (as in yellow wire connected to closed points), any resistance up stream of the coils will reduce voltage to the coils.  And the coil connected to the points that are closed will also consume power and drop voltage while passing.
 Ohm's law   E = I X R.   I = E/R, R = E/I

12.5V / 2.5Ω = 5 Amps   This is the current flowing through the circuit when a coil is pulling power.

When you disconnected the yellow wire, the coil stopped drawing the 5 amps of current through the B/W wire.  And the voltage went from 9.7 up to 12V, a difference of 2.3 V.  Since we know what current caused this voltage change, we can again use ohms law.    2.3V/5A = .46Ω.  You have this resistance upstream from your coils in the path to the battery, and it is this resistance that is drawing down the voltage to the coils.  Each switch contact or other non-solid wire connection in the path can develop resistance and it all adds up.

The voltage drop increases with the current.  Your stock coils were about 5 Ω.  And you would see half of that presently measured voltage drop with stock coils.

I sure hope you are putting those coils on a 750, as a 550 will have a very hard time keeping the battery charged with 2.5Ω primary coils, as they double the power drain from the system.  Stock ignition power ~30 watts drain.   GL coils will increase that to ~60Watts.  And this from a 150 Watt peak system on the 550  (about 40-50 watts at idle speed).

Cheers,

[Paul E.]

Thank you for the lesson in electronics!  I hadn't thought about utilizing Ohm's law. 

I sure hope you are putting those coils on a 750, as a 550 will have a very hard time keeping the battery charged with 2.5Ω primary coils, as they double the power drain from the system.  Stock ignition power ~30 watts drain.   

Uh-oh!  They are definitely going on a 550!  I wonder why the PO would have substituted the GL coils for the stock coils if the 550 will have difficulty keeping the battery charged with the 2.5Ω primaries.   

To try and discover where my excess resistance is occurring I unhooked the blue and yellow wires for the points plate and found that the voltage was 12.46 v for each wire.  When I hooked them back up to the plate the voltage dropped to 9.7 volts.  I disconnected the points plate letting it dangle freely under the exhaust and found the voltage was 12.08 v at the blue and yellow wire.  After reinstalling the plate the voltage read 9.7 again.  So when the plate is installed it causes the extra 3 volts of resistance.  Is this caused by the plate being improperly isolated?? 

While I don't plan on running the bike until I am able to get the correct voltage to the points, how does a voltage of less than 12 volts affect the performance of the bike?

This is great, I'm learning a ton. 

[bollingball]

I was just talking to Mark HondaMan about the new Honda tec points the other day when I was hooking up his Ign box. He said it would be a good idea to clean them with acetone and sand them. It seems they are putting a sealer of some type on them that is not so easy to get off.
Ken

[bollingball]

I think you may have the wires in the wrong place at the points. that is where your isolation occurs. With the fiber washers the pivot also is isolated
I disconnected the points plate letting it dangle freely under the exhaust and found the voltage was 12.08 v at the blue and yellow wire.  After reinstalling the plate the voltage read 9.7 again.  So when the plate is installed it causes the extra 3 volts of resistance.  Is this caused by the plate being improperly isolated??  


Ken

[TwoTired]

No such thing as 3 V of resistance.

Voltage is electrical potential.
Amperage is how much force to flowing through the wires.
Resistance is how much limitation is placed on the amperage flow.


A wire with no current flowing through it (incomplete circuit), will distribute the full voltage from the source throughout. 
When the circuit is completed the voltage will drop commensurate with the resistance present in the circuit.
When you disconnected the points plate, you broke that circuit path and current stopped flowing through it and power wasn't consummed ot voltage dropped when passing through the coil(s).

If there are multiple resistances in the circuit they act as voltage dividers, each dropping a portion of the voltage as it passes through a resistance.  The amount of voltage each resistor drops is directly related to the current passing through the active circuit.

In a simple case, make a circuit with twelve equal resistors wired in series with a 12 V source (unlimited current capability).  Each resistor will drop 1v across it.  With resulting readings of  11,10,9,8,7,6,5,4,3,2,1 Volts at each resistor tie point and referenced to the power source neg terminal.

Calculations become more complex with unequal value resistors, but a similar thing happens when taking voltage measurements mid circuit. Replace 6 of the 1 ohm resistors with one 6Ω resistor and it will drop half the voltage all by itself wherever placed in the circuit loop.

 The ohms and watts law equations are always solvable/predictable when knowing two variables.  It appears you are focusing on just one.
If you multiply your paycheck by X, how much extra will you earn?

I have little doubt that the PO replaced the original coils with what you have because of the easily replaceable ignition leads and never considered power draw or the extra wear of the switches and connector in the path providing that extra power. (imo).

Cheers,

[Paul E.]

I think you may have the wires in the wrong place at the points. that is where your isolation occurs. With the fiber washers the pivot also is isolated
I disconnected the points plate letting it dangle freely under the exhaust and found the voltage was 12.08 v at the blue and yellow wire.  After reinstalling the plate the voltage read 9.7 again.  So when the plate is installed it causes the extra 3 volts of resistance.  Is this caused by the plate being improperly isolated??  


Ken

Ken, what is the correct order for the wires?  My blue wire is currently setup (starting at the end of the bolt and working towards the head):

nut
small washer (metal)
blue wire terminal
washer (metal)
green wire terminal
fiber washer
point post/tab
fiber washer
flat metal point arm
bolt head

the yellow side follows the same ordering. 

 The ohms and watts law equations are always solvable/predictable when knowing two variables.  It appears you are focusing on just one.
If you multiply your paycheck by X, how much extra will you earn?

So the known variables that you'll use will be:
(V) battery voltage = 12.5V
(R) coil resistance = 2.5 ohms
which allows you to solve for the amperage (I)

Then you can use your known battery voltage in conjunction with the voltage found at any point in the electrical system to find the resistance at that point.  Such as how you found the resistance earlier: 12V - 9.7V =2.3V and then 2.3V/5A = .46Ω.

[TwoTired]

Then you can use your known battery voltage in conjunction with the voltage found at any point in the electrical system to find the resistance at that point.  Such as how you found the resistance earlier: 12V - 9.7V =2.3V and then 2.3V/5A = .46Ω.

...And this resistance is far too high for an accumulation of wire, crimp connections, switch contacts, and fuse terminal electrical paths.

Btw, .46Ω @ 5 amps means 11 watts thrown away as heat from your 150W peak alternator instead of being used to charge the battery.

Cheers,

[Paul E.]

11 watts is not something I want to throw away, especially if my coils might have a challenge keeping my battery charged as is.

Where the wires connect to the points via the small bolt--should a fiber washer be in between the yellow/green wires and blue/green? Or should they be in contact with each other?  The picture I went off during reassembly was not a close up showing exactly how it was, so it is very possible that I might have switched the order around when reassembling...

[TwoTired]

The purpose of the fiber washers is to keep the blue (or yellow) wire, and condenser lead (connected together), from connecting to the mount plate, so the point movement can control this event.
Fiber washers are insulators.

[Paul E.]

Hmmm...  So if the order of my wires is correct where else might the resistance be occurring within the setup?  Is it correct to assume that the problem occurs within the points plate area since the voltage going into the blue and yellow wires when not hooked up is at an acceptable number? 

As Ken suggested, I will grab some acetone and sand the points in case they still have any residual sealer left on them.

Really i'm not to certain what to be looking for that might cause the resistance.  Since the value is higher than what could be accounted for in dirty connections it seems like it should be something obvious.  But seeing as I don't have anything to compare it to, it's hard to detect.

[TwoTired]

Hmmm...  So if the order of my wires is correct where else might the resistance be occurring within the setup?

I'm close to giving up on this thread.

What part of ...

...And this resistance is far too high for an accumulation of wire, crimp connections, switch contacts, and fuse terminal electrical paths.

...don't you understand?  You can't believe anything between the battery and the coil connection terminals can have a fault or have a faulty connection?

Is it correct to assume that the problem occurs within the points plate area since the voltage going into the blue and yellow wires when not hooked up is at an acceptable number? 

Nope.  You're looking for love in all the wrong places. 
The voltage drop problem is not in the points plate area.
The problem(s) are up stream of the coils between their power connection and the battery terminals.

When you remove the point plate from the engine block, you are essentially adding a switch made up of the point plate contact area and the engine block contact area.  The voltage goes up because you've broken the circuit in which current can flow when you remove he plate.  Voltage distributes unimpeded in a circuit where no current flows.  So everything, including the unconnected plate itself will assume the voltage being fed to the coils (assuming the points are closed).

I'm at a loss as to how to make this any plainer.

Good luck!

[Paul E.]

I apologize for not catching onto what you're saying quicker.  I'll try harder.