Not running on left cylinder, has sparkcb360

Posted this problem on Honda twin a while back but figured I would pick everyone's brain on here as well. My honda cb360 stopped running on the left cylinder. It has good spark and I checked the timing and it all looked good. I used a test light to check the wires going to the points and I only got a green light on the wire going to the right coil. This lead me to believe I had a bad coil. Replaced that today and now I can't get the test light to light up on the wires to either coil. Bike still runs on the right cylinder and battery is fully charged. Tried checking timing again and couldn't get a light to come on. Anything simple I am missing?

Update, started it up and gave it some gas and the left side started firing, pulled the right plug and it ran on the left as long as I held the throttle.

Also the right hand side sputtered a bit and a white puff would come out of the back of the carb when it did, but I think that is an unrelated issue


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Dead (or dying) battery is one of the more common causes of an early Honda twin firing on only one cylinder. It's easy to rule out, too.

Grab some jumper cables and run them from your car to the bike (keep the car turned off). Start the bike with the cables attached and see if both cylinders fire.

Report back.

I had the battery on the charger all day yesterday but I will try that when I get home!

dantyler92 said:

I had the battery on the charger all day yesterday but I will try that when I get home!

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Cool. For what it's worth, a bad battery won't hold a charge, so putting it on a charger won't do much. The jumper cables should allow us to remove this from the list of possible causes, though.

dantyler92 said:

Update, started it up and gave it some gas and the left side started firing, pulled the right plug and it ran on the left as long as I held the throttle.

Also the right hand side sputtered a bit and a white puff would come out of the back of the carb when it did, but I think that is an unrelated issue


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Click to expand...

Sounds like carb sync issue. Rule out the electrical issues first, then I'd go through and adjust cam chain, valves, timing and carb sync according to the manual.

Thanks everyone I will try hooking it up to the car when my roommate gets home with the cables. I turned the bike on and the electric start worked fine so I'm not sure if that means the battery is ok?
And would a bad battery cause the test light not to work when I am trying to time the bike?


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Sometimes, but not always. If electric start it working OK, that's usually an indication of a good battery, but it's worth testing just the same.

Hey guys sorry to take so long getting back! I pulled the carbs apart and synced them and that did the trick. The sync screw was super loose. I don't know what was causing the issue with not getting power from the coil but at least I know that's good now too! Thanks for everyone's help you all are the best


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