Exhaust popping at idle and engine dies with choke ON

Hey guys, on my 75 Honda CL360 I've been building for almost 3 years now I have two issues: there is a popping noise at idle and when I put the choke on the engine dies.
The carbs were rebuilt by PJ but I may not have them adjusted just right. Any suggestions on where to start?

Popping could be late ignition timing, check that first.
- Valves may also need to be adjusted.


Then sync (when engine is warm).

I just saw your reply but this morning I made sure the jets were clean (unclogged) and noticed that the popping is only coming out of the upper exhaust which is the right hand side cylinder. I also noticed that occasionally a pop will make the carb move, it looks like its being kicked out by the engine. Not sure if that makes sense to anyone. I tightened down the carb boot but the carb still moves on random pops.
I've adjusted the timing multiple times on this bike but I can do it again this weekend. It's pretty annoying how much it pops.

That sounds like an air leak. getting in around the carbs or the exhaust. also if the engine is warm and you put the choke on it should stall, the choke is only needed when doing a cold start.

On my 360, if it is backfiring back through the carb, the issue has been late ignition timing every single time. But that's not to say you don't have an air leak.

Adjust the valves, time the ignition, start it up, spray some carb cleaner around where the intake manifold butts against the head and also make sure the carbs are fully seated inside the boots. These 360's are way to finicky.

Thanks for all the tips. I just ordered some new points because I've had to adjust these so many times they're probably just worn out, hoping new ones will hold their adjustment longer. I'll pick up some carb cleaner too, I couldn't remember what I'm supposed to use to find air leaks, I just knew WD40 doesn't work.
I'll report back when I have more info. Also want to get some photos taken and post them here. Thanks again.