Topic: please help me troubleshoot ignition failure on my sons 81 cb650 c

[basket case]

My son got a 1981 cb650 custom back in march that was stored in a barn for several years. I trucked it home and we cleaned it up, changed the oil, cleaned the carbs and tank, replaced the battery, sparkplugs and air filter.  The bike started right up and ran great! 

To make the bike safe and reliable we decided to replace the tires (weather checked) chain and sprockets.  We rebuilt the front calipers   and carbs and replaced the fork seals. 

we just finished the work a couple of days ago and planned to start it up and check it out.  My son got home from school and tried to start it.  He said it fired, ran a minute then stalled when he began removing choke.  When I checked the bike the starter didn't operate.  The fuse was blown so I replaced it.  Still no luck. I traced the problem to the starter coil (solenoid) and replaced it temporarily with a universal replacement.  The bike turned over great but wouldn't start and quickly flooded. I checked for spark and found none. this bike has a CDI or electronic ignition and I am clueless as to troubleshooting this ignition.

My son admitted that when the bike wouldn't start he got frustrated and just kept cranking on it until it stopped and smoked.

I am hoping that he won't need to replace all the ignition parts but I don't know what to look for other than the 12vdc, so I could use help testing the ignition components.  How do I test the following:

• Ignition Coils
• Pulse Generator
• Spark Units (Ignitors)

Any help would be great!

[csendker]

This is beyond my capabilities, but I know that coil testing is in the FAQ's --> http://www.sohc4.us/forums/index.php?topic=5752.msg8383#msg8383

[TwoTired]

Before you go too far into TS mode check the Off-Run-Off switch on the bars.
Some of us have been known to bump that thing and wonder why the bike won't work.

Do check for 12 v at the coils and at the igniter units (Blk/Wht) wires.
I think I would also verify that the green wires at the units have continuity to Bat Negative.

Each pulser is a simple coil winding.  Disconnect them and measure for resistance with a meter.  I don't know what they are supposed to be, but if you get infinity, that can't be good.

Doesn't your repair or shop manual say how to check them?

I only see have wire diagram.
http://oldmanhonda.com/MC/WiringDiagrams/MCwiring.php

I expect you need an oscilloscope or peak hold AC meter to measure the CDI output.

Cheers,

[byidesign]

The CDI on the cb650 79-82 is a split CDI
    system {one pickup/CDI/coil} per
     two cylinders, same as my cb650sc, the fact you get
       "nothing" {usually one set dies...and
       the other set still sparks}   makes me think
      you need to check all wire connections/ ign switch
        fuses/holders/kill switch/grounds, for poor,or dirty
         connections {especially one's behind the headlight.}
                make sure you are getting your battery voltage
           where it needs to go first..
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                            Bruce