1982 cb650 nighthawk ignition troubleshooting

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BenHume
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Joined: Sat Feb 25, 2017 8:28 pm

1982 cb650 nighthawk ignition troubleshooting

Postby BenHume » Wed Mar 15, 2017 3:59 pm

Hi! I was having trouble keeping my bike running once it was warmed up, and so I pulled the plugs and tested them once warm and found that the plugs for cylinder 2&3 weren't firing. After letting it cool, spark returned. Both of my ignition coils appears to be originals and both tested a bit low, so I decided to order new coils/wires/caps. Sadly once the new ones were installed and tested (all sparked beautifully​) I warmed up the bike and experienced the same issue... The plugs for 2&3 cylinder weren't firing.

This leads me to believe that the issue must lie in the CDI boxes or the pulse generator. I don't know how to test either, but something is malfunctioning once the bike warms up. Any help would be appreciated.

-Ben

cb650
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Re: 1982 cb650 nighthawk ignition troubleshooting

Postby cb650 » Thu Mar 16, 2017 5:08 am

first bet would be the pulse generators. You can swap them to to the other cyls just with the connectors and see if it changes to the other cyls.
Did you clean the tank out?!?!?!?!

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Folsoml
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Re: 1982 cb650 nighthawk ignition troubleshooting

Postby Folsoml » Thu Mar 16, 2017 8:38 am

I had the exact problem with a CB750C and it was the pulse generators. Once they got hot, something was shorting out.
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BenHume
Posts: 4
Joined: Sat Feb 25, 2017 8:28 pm

Re: 1982 cb650 nighthawk ignition troubleshooting

Postby BenHume » Sat Mar 25, 2017 6:07 pm

Problem Solved. It was indeed the pulse generator! I even replaced the ignition coils thinking it was them, but if I had known I could have tested that and saved some money. Oh well, I bought a used pulse generator and it works. Ignition troubles are over, now I need to figure out why carb 1 is running so rich!


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