School me on points and condensers

[lowtops]

History: I have a 1972 CB175 that I have been restoring over the past couple of years. I rebuilt the motor about a year ago and have since put 11 miles on it. I could not find suitable mufflers and it was just to loud to ride. Plus I don't have a tag yet so just I have just been terrorizing the neighborhood for those 11miles. I recently found mufflers for it and am ready to get it on the road. I have not had any issues since the rebuild until now. I should also mention that I crank it at least every week to keep things fresh.

Problem: My problem is it won't start now. Battery is good, compression is good, plugs are good, and it's getting fuel.

Question: Is there any way to test the coil and condenser? I tried using a voltmeter on the coil and the voltmeter went haywire and now the digital display does not come on. I have recently learned that you cannot use a digital voltmeter on "pulsing" power sources. True or false? I used an analog voltmeter after this and was getting 5V from the spark plug wires and the coil. Thoughts? Bad coil?

Should there be a spark between the points when they open? I am thinking there should not be, but I am new to points systems and don't know. I have new points on the way.

Is there a way to test the condensor? The repair manual states to touch the case of the condensor to the negative post on the battery and the positive wire of the condensor to the poisitive post on battery. Let it charge for a few seconds and touch positive wire to the case of the condensor if there is a spark it can be presumed to be good. I did this and nothing, both with the old condensor and the new one. Any thoughts or suggestions?

Thanks for reading all of this.

 

[valentine]

History: I have a 1972 CB175 that I have been restoring over the past couple of years. I rebuilt the motor about a year ago and have since put 11 miles on it. I could not find suitable mufflers and it was just to loud to ride. Plus I don't have a tag yet so just I have just been terrorizing the neighborhood for those 11miles. I recently found mufflers for it and am ready to get it on the road. I have not had any issues since the rebuild until now. I should also mention that I crank it at least every week to keep things fresh.

Problem: My problem is it won't start now. Battery is good, compression is good, plugs are good, and it's getting fuel.

Question: Is there any way to test the coil and condenser? I tried using a voltmeter on the coil and the voltmeter went haywire and now the digital display does not come on. I have recently learned that you cannot use a digital voltmeter on "pulsing" power sources. True or false? I used an analog voltmeter after this and was getting 5V from the spark plug wires and the coil. Thoughts? Bad coil?

Should there be a spark between the points when they open? I am thinking there should not be, but I am new to points systems and don't know. I have new points on the way.

Is there a way to test the condensor? The repair manual states to touch the case of the condensor to the negative post on the battery and the positive wire of the condensor to the poisitive post on battery. Let it charge for a few seconds and touch positive wire to the case of the condensor if there is a spark it can be presumed to be good. I did this and nothing, both with the old condensor and the new one. Any thoughts or suggestions?

Thanks for reading all of this.

Found this for testing coils. I've never personally had a coil go bad...

Ignition coils. Measure the resistance between the primary (low-tension) wire and ground or ground terminal. It should be very low. Like .5 to 1.5 Ohms. The primary wire is the small wire going to the CDI box or points. Next measure the secondary (high-tension) wire and ground. (Note that on most bikes these days, the coil mounting bar, that passes through the coil and mounts it to the frame, is the ground for the coil primary and secondary wires.) This should be quite high, like 6000 to 13000 ohms. If the coil is out side the specs given in the shop manual the coil might be bad. Sometimes, a coil will work OK when cool but fail when it warms up. Let them cool and they work again. They make machines that will test coils under load. They are nice to have but can be pricey. Remember to take the plug cap off for the test. The cap can add 300 ohms resistance.

My guess is that it's your points/condenser. Your points will spark when they are in the process of opening if your condenser is bad....

 

[valentine]

Looks like the guy has a pretty good write up on points/condensers here.

Dan's Motorcycle

 

[lowtops]

Two very good replies. Thanks for the info. I already have Dan's website saved, I just forgot about it. Thanks again.

EDIT: Thanks for the reminder valentine. Everything I ever wanted to know about points and condensors.

 

[lowtops]

Any thoughts on my digital voltmeter? Will "pulsing" power sources ruin it?

 

[valentine]

Any thoughts on my digital voltmeter? Will "pulsing" power sources ruin it?

Got me there. I don't know too much about electrical..