Author Topic: '80 CB650c ignition unit or pulse generator at fault?  (Read 580 times)

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Offline ABikeNamedTrouble

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'80 CB650c ignition unit or pulse generator at fault?
« on: September 16, 2012, 10:09:10 AM »
Hey folks,

It's been awhile since I've been on the forum.  I've enjoyed nearly a year of trouble-free riding (even decided to rename the bike from "Trouble" to "Russel" after my girlfriend's amazing grandfather who is 93 and looks and lives like he's 70). 

Anyway, I was riding home from said girlfriend's house the other night and suddenly two of my cylinders stopped firing.  I amazingly made it home fine (even made it up to 70mph!) on two out of four.  I assumed it was a busted ignition coil but upon testing, it's not the coil.  So I'm left with two possibilities as far as I can see:

1) One of my CDI units is broken.
2) One of my pulse generator units is broken. 

The trouble is, I don't know how to isolate them from eachother.  It seems from the wiring that the 1-4 pulse generator is wired directly to the 1-4 spark unit and vice-versa. 

I've already repaired the CDI units, as you can see in the thread linked in my signature.

So my question is:  Which one is the most likely culprit?


As always, thanks in advance for the help.
Adam. 
- Adam

1980 CB650c Custom
Keihin PD mechanical carbs
Stock air box and 4-4 exhaust
http://forums.sohc4.net/index.php?topic=97504.0

Offline onepieceatatime

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Re: '80 CB650c ignition unit or pulse generator at fault?
« Reply #1 on: September 16, 2012, 07:09:07 PM »
Swap the ignition unit to find out. If the opposite cylinders start firing, you know that it is the ignitor, if not, you know it is the pulse generator.
1965 CA77
1972 CB750K Ol' Sarge
1974 CB450K7
1977 CB750K7
1977 CB750K7
1980 CB650C
1982 CM450A
1997 GL1500SE