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Discussion Starter #41

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Well I think it's nearly time to wave the white flag.
Installed new CDI from the magician and still no spark. I'm assuming that it must be the stator due to the high brown/light blue wire reading as per below. Short of re-checking all the wire connections I'm lost.

Blue/White = 86 Ohms
Green/Pink = 136 Ohms
Brown/Light Blue = 216 Ohms

Anyone got a functioning Stator/pickup they're willing to part with?
 

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Discussion Starter #43
It sounds like the stator is the fault. BUT first with the engine OFF, key out and all connectors connected back probe each wire connection. You're looking for zero ohms at each and every spade connector in the connector plug.
What are the coil readings?
Are you checking for spark with on plug and wire installed and connected?
 

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I'm thinking so too. When I try to start the engine with with my voltmeter on the blue & white wires from the stator I get quite low readings.
Original Coil:
Primary Resistance: 0.6/0.7 ohms
Secondary Resistance: 8.07 K ohms

Aftermarket Coil:
Primary Resistance: 1.0 ohms
Secondary Resistance: 14.3k ohms

I am checking for spark with plug>NGK suppressor cap>wire>Coil. One of the spark plugs is tightened down into the head and the other i'm holding against the head bolt to ground.

BUT first with the engine OFF, key out and all connectors connected back probe each wire connection. You're looking for zero ohms at each and every spade connector in the connector plug.

What connector plug do you mean?
 

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Discussion Starter #45
Each of the 3 CDI/Stator connectors. The spade connectors inside each plug can become loose or corroded so that there's a poor connection which will affect the operation.
The voltage coming of the power supply circuit, Blue and White, is measured in AC volts not DC.
 

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All wiring from Stator has new plugs/connectors. When I crank the engine over I get 14-16 volts AC from the Blue/White wires from the stator. When I crank the engine over I get 7-10 volts AC from the Yellow/Green wires from the CDI that go to the coil. At the risk of sounding stupid you said back probe each wire. Do mean zero ohms between each spade connection or between negative and the connection? Is it worth just going the Ignitech route? I've read Nebula's thread about making the Ignitech conversion, i'm wondering whether its better in the long run anyway.
 

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" the primary pickup coil, the aluminum piece outside the rotor
The resistance should be about 207 ohms. New Spec 203 Ohms"

i tested mine because there is no spark.
Mine read about 197 ohm....Still good??

Still need to buy new plug caps.
But i think my problem is a kill switch problem. The PO did a wire harnass chop...Made it simpler, i think something is wrong or loose.
Still testing.
 

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Discussion Starter #48
197 may give you enough signal for spark. Usual problem is too much resistance.
You can disconnect the Black w/White pigtail wire at the CDI unit and see if you get spark. That is the circuit for the kill function, disconnecting means there's no way to manually turn off the ignition.
 

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Thank you! So no worries there..
That wire is loose, nothing connected. but still no spark.
Will test again this weekend. Also going to change the coil for a gm one. But forgot to buy cables and endcaps....
 

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Not sure if it's been mentioned but all 'stock' readings are +/-10% to take into account different meters
 

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These tests are used to check the CDI system. There are no valid tests for the CDI unit so this is an elimination process. If all these tests are good then the CDI is at fault. Before replacing a CDI all these components have to test good.
Use a multi-meter and set it to measure electrical resistance in Ohms.

Coil Test:Primary Side.Measure the resistance between the Yellow and Green wires.
The Yellow and Green wires being measured will be coming out of the spark plug coil.
The resistance should be less than 1 Ohm. Spec is .35 to .55 ohms
Secondary Side: Measure the resistance of the spark plug wires with the plug end caps removed, they unscrew. Insert a probe into each wire. Spec is 7.2K ohms to 8.8K ohms
Plug End Caps: Measure the resistance of the plug end caps. Spec is 5K ohms. Replacement part number is NGK XD05F

Stator Tests:
The connectors used are found under the left side cover
Measure the resistance of the Pink and Green wires.
The Pink and Green wires to measure will be going into the bundle that goes along the frame and eventually to the stator. This is the advancer pickup sensor
The resistance should be about 135 Ohms. New Spec 129 Ohms

Measure the resistance between the White and Blue wires.
These wires to measure will be going along the frame and eventually to the stator also. This is the CDI power source
The resistance should be about 85 Ohms. New Spec 84.2 Ohms

Measure the resistance between the Brown and Light blue wires.
These wires to measure will be going along the frame and eventually to the stator also. This is the primary pickup coil, the aluminum piece outside the rotor
The resistance should be about 207 ohms. New Spec 203 Ohms

The stator ohm readings listed can exceed the old spec by no more than 1 ohm, more than that will have a negative effect on the timing advance.
The New Spec was obtained by measuring 2 NOS stators, fresh unused old stock early model with the bullet Blue and White wire connectors.

Run/Kill and Ignition switch Tests:
Connect one probe to the Black w/White tracer pigtail wire coming out of the main wiring harness that connects to the CDI unit. Connect the other probe to the negative battery terminal. The results should be:
Ignition switch on, Run/Kill switch in Run position: Infinite Ohms reading meaning an open circuit
Ignition switch on, Run/Kill switch in Off position: Zero ohms or close to that showing the circuit is closed/completed to ground
Ignition switch OFF, Run/Kill in any position: Zero ohms or close to that showing the circuit is closed/completed to ground

Alternator Tests: Select/connect to one Yellow wire with a probe. Connect the other probe to one of the remaining 2 Yellow wires, resistance should be below 1 ohm. Repeat twice using a different wire each time. If the readings are good then test each of the Yellow wires with one probe connected to ground. There should be an Infinite ohms reading meaning none of the charging coils is shorted to ground.

NOTE: ​Some VOM's are auto-ranging meaning they switch ohm scales as needed and some are range selectible. If you have to select the range be sure to do that matching the expected ohm range.
So if the test result are the red numbers it’s the CDI that’s causing the problem. I’m wondering if when you said the “test are good” then CDI is at fault means these numbers.
 

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That's correct. If all your results match the red numbers then you have eliminated all the components in the ignition system as the source of the problem. Since we have no specific test for the CDI, we identify it as the problem by eliminating all the other possibilities.
 

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Are these electrical ohm test with engine one or off? I assume off... the test on the coil, engine off, pegged my ohm meter, off the chart... I have an old on with the needle/scale. That’s red on yellow black on green, vice versus does the same.
 

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Discussion Starter #56
Yes, engine off.
An analog VOM works the same as the digital versions, just a bit slower in getting a stable reading. Check your ohm settings, since the coil is less than 1 ohm you would need to use the lowest setting.
If you haven't changed the batteries in it for awhile that would be a good thing to do.
 

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These tests are used to check the CDI system. There are no valid tests for the CDI unit so this is an elimination process. If all these tests are good then the CDI is at fault. Before replacing a CDI all these components have to test good.
Use a multi-meter and set it to measure electrical resistance in Ohms.

Coil Test:Primary Side.Measure the resistance between the Yellow and Green wires.
The Yellow and Green wires being measured will be coming out of the spark plug coil.
The resistance should be less than 1 Ohm. Spec is .35 to .55 ohms
Secondary Side: Measure the resistance of the spark plug wires with the plug end caps removed, they unscrew. Insert a probe into each wire. Spec is 7.2K ohms to 8.8K ohms
Plug End Caps: Measure the resistance of the plug end caps. Spec is 5K ohms. Replacement part number is NGK XD05F

Stator Tests:
The connectors used are found under the left side cover
Measure the resistance of the Pink and Green wires.
The Pink and Green wires to measure will be going into the bundle that goes along the frame and eventually to the stator. This is the advancer pickup sensor
The resistance should be about 135 Ohms. New Spec 129 Ohms

Measure the resistance between the White and Blue wires.
These wires to measure will be going along the frame and eventually to the stator also. This is the CDI power source
The resistance should be about 85 Ohms. New Spec 84.2 Ohms

Measure the resistance between the Brown and Light blue wires.
These wires to measure will be going along the frame and eventually to the stator also. This is the primary pickup coil, the aluminum piece outside the rotor
The resistance should be about 207 ohms. New Spec 203 Ohms

The stator ohm readings listed can exceed the old spec by no more than 1 ohm, more than that will have a negative effect on the timing advance.
The New Spec was obtained by measuring 2 NOS stators, fresh unused old stock early model with the bullet Blue and White wire connectors.

Run/Kill and Ignition switch Tests:
Connect one probe to the Black w/White tracer pigtail wire coming out of the main wiring harness that connects to the CDI unit. Connect the other probe to the negative battery terminal. The results should be:
Ignition switch on, Run/Kill switch in Run position: Infinite Ohms reading meaning an open circuit
Ignition switch on, Run/Kill switch in Off position: Zero ohms or close to that showing the circuit is closed/completed to ground
Ignition switch OFF, Run/Kill in any position: Zero ohms or close to that showing the circuit is closed/completed to ground

Alternator Tests: Select/connect to one Yellow wire with a probe. Connect the other probe to one of the remaining 2 Yellow wires, resistance should be below 1 ohm. Repeat twice using a different wire each time. If the readings are good then test each of the Yellow wires with one probe connected to ground. There should be an Infinite ohms reading meaning none of the charging coils is shorted to ground.

NOTE: ​Some VOM's are auto-ranging meaning they switch ohm scales as needed and some are range selectible. If you have to select the range be sure to do that matching the expected ohm range.
1980 cb400t

Hello all,
I am trying to wake this Hawk up from its 28 year slumber and I have a question regarding the stator ohm test. Jim says in his post,"The stator ohm readings listed can exceed the old spec by no more than 1 ohm, more than that will have a negative effect on the timing advance." What if the readings are less than spec?

My stator ohm test results are:
Pink and green=116.4 (spec=129)
Blue and white=82.4 (spec=84.2)
Brown and Lt blue=204 (spec=203)

Ok, that last one wasn't less than spec but I felt it should be included.
All the other diagnosis results were good except that the plug caps were 5.1 and 5.28 (spec=5).

I not able to test the ignition switch as it is still in my online shopping cart, but the handlebar kill switch seems to work. It grounds the black w/white stripe wire, tested at the connector near the cdi, when in the kill position. Otherwise the black w/white stripe to ground remains open.

I have attached a picture of my ignition circuit jumper just in case this method of hotwiring (red to black only) prevents a spark. Because, I just don't know what I don't know. IMG_20190105_160120.jpg
Thanks,
Shain
P.S.- To be clear,I'm not getting any spark.
 

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Discussion Starter #60
I'd guess that your VOM is just reading low, try a new battery in it or borrow another one. With your readings the CDI unit would be at fault assuming the coil passed it's tests.
The Red to Black jumper will have zero effect on spark. The ignition switch is only used to kill the CDI circuit.
 
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