Topic: cylinders 1 and 4 misfiring

[wildmanrem]

Hey guys i am an extremely new member, and have an 81 cb650 custom i bought it as my first bike and the bike needs some work but the issue i came to day to get some kind of an answer to is that my outer two cylinders, (1 and 4) are not even firing i know they both hook up to the left ignition coil, which i found out after a night of pushing it home from a matter of misfiring, charging, and battery issues i bought a brand new ignition coil from amazon (and no i was not running on just 2 cylinders it just went out when i was out riding) the ignition coil came in today and i got everything hooked up and nothing. It still isn't firing on those two cylinders, any ideas?

[DH]

I'm not familiar with the 650, but believe it has electronic ignition? Electronic ignition usually has components (modules) that turn the ignition coils on and off to fire the plugs. There may be an issue with the module, sometimes called an ignitor, for #1 and #4.
Might be a bad ignitor or wiring and associated componantry. It could even be a bad or corroded connection somewhere. Best to download a service manual for your bike from this site
and start reading up. You'll find most here will suggest/guide you through troubleshooting rather than simply replacing parts.
That's is good advice, you'll learn that way, and troubleshooting is FREE. Parts are expensive. Perhaps there is a 650 guy who can
elaborate furthur....you might edit the title of your post to include the term cb650 in it.

[DaveBarbier]

If you pull the plugs after the engine was running, are they wet with fuel?

How about if you pull the #1 plug but reconnect it to the plug wire and hold it against the engine do you see a spark when you try and start it? Same test with #4.

Those tests will help determine which direction to go. Fuel/carbs or ignition.

[DH]

And to add, if you do have to troubleshoot the ignition system, the troubleshooting procedures for that system are
reasonably easy and straightforward. The system diagnosis is 6 well illustrated pages in the factory service manual.
Ability to use a volt meter  (or knowing someone who can) is a plus. Simple measurements.

[wildmanrem]

Thanks for the quick response and all the great suggestions! i've got a buddy that says he can bring over his multimeter tomorrow and i will test it and post the results

[754]

It is ignition problems..

[wildmanrem]

okay so i just had some time to check it all, and the battery had 12.52v with the key off, 12v with the key on, and 11.59v to the black and white wire when grounded to the engine, and when connected to the blue wire it only had 10.33v i checked a couple times and got a few different readings but they were all very close to these readings