How to Check Out CDI on 1997 Yamaha 80hp

[fishfun83]

My 1997 Yamaha 80 horsepower C80TLRV is missing on cylinder 2 only. This afternoon I replaced the CPS hoping that would be the easy fix but it did not solve the problem. Next I need to check the CDI and confirm it is dead before I spend $600 on a new one. My Service Manual says I need to measure resistance at the 3 plugs receive information from the Charge Coil, Pulser Coil and the Crankcase Position Sensor. Some youtube videos I have seen show measuring voltage with the engine cranking. Any help would be appreciated.

[99yam40]

you can measure resistance of the coils,
but the best in my opinion is measure the peak voltages into and out of the CDI at cranking and at upper RPMs too as the service manual calls for.

[fishfun83]

you can measure resistance of the coils,
but the best in my opinion is measure the peak voltages into and out of the CDI at cranking and at upper RPMs too as the service manual calls for.

I am trying to check out the CDI and my Yamaha Service Manual makes no mention of measuring voltage. Which service manual are you referring to? I am using the official Yamaha Service Manual LIT-18616-01-69

[99yam40]

Do not know anything about your motor or manual, but my C40 has the spec and procedures for my motor in the electrical /ignition pages

[cpostis]

I am trying to check out the CDI and my Yamaha Service Manual makes no mention of measuring voltage. Which service manual are you referring to? I am using the official Yamaha Service Manual LIT-18616-01-69

Well, that is the right manual for your C80TLRV, and it does not give you the peak voltages specifications for your CDI. I'm gonna look up your CDI part # and see what other engines it is used on. Then I'll see if I have a manual for it to get you the specifications you need. It might not be correct though.

Maybe our friend Boscoe can get them and confirm!!!

[fishfun83]

Thanks. Hope Boscoe can respond. I am really struggling.

[fishfun83]

One more thing. I have not tested the Pulser coil because rodbolt17 has stated that the pulser coil only controls spark to cylinders 1 and 3. Question is can the charge coil be bad and only fire on 1 and 3?

[cpostis]

I am trying to check out the CDI and my Yamaha Service Manual makes no mention of measuring voltage. Which service manual are you referring to? I am using the official Yamaha Service Manual LIT-18616-01-69

Well, that is the right manual for your C80TLRV, and it does not give you the peak voltages specifications for your CDI. I'm gonna look up your CDI part # and see what other engines it is used on. Then I'll see if I have a manual for it to get you the specifications you need. It might not be correct though.

Here it is, note no peak voltage at cylinder 2 while cranking. It' from a 2000 model year using the same CDI as yours.

[IMG]CDI.80 by Charles Postis, on Flickr[/IMG]

Maybe our friend Boscoe or others can confirm them?

[cpostis]

One more thing. I have not tested the Pulser coil because rodbolt17 has stated that the pulser coil only controls spark to cylinders 1 and 3. Question is can the charge coil be bad and only fire on 1 and 3?

Hmm... I just now read that post. Besides ohming out the CPS, are you sure you have a good connection from it to the CDI?

[fishfun83]

I just replaced the CPS and it is still not firing on cylinder 2. The connector between the CDI and the CPS looks great. No corrosion. Other than just looking at the connector, not sure how I would verify the connectivity between CPS and the CDI.

[cpostis]

I just replaced the CPS and it is still not firing on cylinder 2. The connector between the CDI and the CPS looks great. No corrosion. Other than just looking at the connector, not sure how I would verify the connectivity between CPS and the CDI.

Well to this I am not sure. But, maybe you can see if at least you DO NOT have an open wire to the CDI by ohming between the two terminals in the connector going to the CDI?

Others?

Where does Cyl 2 get its primary voltage from. Pulsar, Charge, Lighting coil? I know all coil leads go into the CDI, and all primary voltage is fed from the CDI to all ignition coils. Just tryin' to learn and see if my inquisitiveness can help others on the way.

Thanks!!

[99yam40]

I do not know why the manual does not show specs for #2, but it seems strange they do not have spec for #2 out of CDI as the CDI has to send voltage to the #2 coil to produce the spark does it not?
It just does not use a pulser coil to tell it when to send it on to the ignition coil is my thoughts

I would think the charge coil inputs voltage into the CDI for all 3 sparks, because there is nothing else to get that voltage from unless the CDI has something inside to step up voltage

[fishfun83]

Well I know that the CPS is good because I just replaced it. There is no lighting coil on this engine. Based on what others are saying, the CPS triggers Cylinder 2. Can the Charge Coil be bad and work on 2 of 3 cylinders. Can the Pulser coil be bad and cause number 2 Cylinder not to fire but fire on 1 and 3? There is no way I can tell from the schematic in the manual. Guess the best I can do is to:
1. Make certain there is a good connection between the CPS and the CDI
2. Check the resistance of the Pulser Coil to make certain it is within spec.
3. Check the resistance of the Charge Coil to make certain it is within spec.
4. Check wire from CDI to the number 2 Ignition Coil to make sure it is in good condition and not grounded.

and last but not least

Check the resistance values given in the manual for the CDI, although the manual says I need a analog volt meter to measure resistance which I don't have.

[99yam40]

lighting coil on Yamahas feed the RR to keep the battery up. I would think this C80 charges a battery while running does it not?

Just because you installed a new CPS does not mean it is putting good voltage into the CDI.

IMHO if the Charge coil, pulser coil, and CPS have the proper voltages going into the CDI, but is not sending out the proper voltage out to all plug coils then either the CDI is bad or there is a problem with the wiring where you are measuring it.
Is it too low, or too high?
does it even have any out put to #2?

[cpostis]

Well I know that the CPS is good because I just replaced it. There is no lighting coil on this engine. Based on what others are saying, the CPS triggers Cylinder 2. Can the Charge Coil be bad and work on 2 of 3 cylinders. Can the Pulser coil be bad and cause number 2 Cylinder not to fire but fire on 1 and 3? There is no way I can tell from the schematic in the manual. Guess the best I can do is to:
1. Make certain there is a good connection between the CPS and the CDI
2. Check the resistance of the Pulser Coil to make certain it is within spec.
3. Check the resistance of the Charge Coil to make certain it is within spec.
4. Check wire from CDI to the number 2 Ignition Coil to make sure it is in good condition and not grounded.

and last but not least

Check the resistance values given in the manual for the CDI, although the manual says I need a analog volt meter to measure resistance which I don't have.

Does the wiring diagram you have look like this?

[IMG]80 Diagram by Charles Postis, on Flickr[/IMG]