Intermittent Rough Running on DOHC K...

[jwaltmire]

Hey Friends,

I've got an issue on my 79' K that I just can't seem to kill. Every once and a while, my engine starts running rough-- characterized by a deeper timbre (almost like it's getting too much fuel), jerky acceleration, and lots of popping. The popping sounds like it's coming from either the #1 or #2 cylinder (I noticed the popping mostly from the left side when I had the stock 4into2 exhaust on there). The strangest part of the issue is that it comes and goes on it's own, and usually only lasts for about 30 minutes of riding time.

Here are a few more details about the bike and the issue:

- Since encountering the issue, I have bored out my cylinders to 836cc, installed a MAC 4-into-1 exhaust, installed new spark plugs and a new ignition coil, and re-jetted and fully cleaned/rebuilt my carbs. I'm running the stock airbox with a newly replaced K&N filter. The issue has happened intermittently throughout all of these changes.
- The rough running seems to happen after I accelerate somewhat aggressively, and it usually doesn't correct itself until I've ridden at highway speeds for a while.

Before I rejetted my carbs, the bike was running on the lean side, so it seemed implausible that I was somehow flooding the engine with gas. However, I'm still thinking that it's a fuel delivery issue, given the intermittent nature.

Anyone experienced anything like this? What can I try next?

Thanks,
J

[TOOLS1]

Intermittent is usually an ignition problem. I would start checking all the ignition parts, and the charging system.
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