1976 KZ back firing from one cylinder

Backfiring through a carb may result from insufficient clearance on the intake valve.

When the valve fails to fully close, combustion escapes through the valve and blasts its way backwards through the intake port and carb.

Good Fortune!

Hi Patton,
The backfiring happens in the exhaust and stops when I pu the choke on...

Clabedan wrote: . . . The backfiring happens in the exhaust and stops when I pu the choke on...

Popping on deceleration may result from pilot circuits that are too lean, for whatever reason, and may sometimes be reduced or eliminated by slight enrichment, say 1/4 turn of the pilot adjustment screws (when the carbs are in otherwise clean and in good condition with correct size pilot jets, correct fuel levels, etc.).

In this instance, would suspect that the choke is serving to enrichen the mixture provided by overly lean pilot circuits (due to whatever reason).

Good Fortune!

well in fact the backfiring is constant at idle, not on deceleration... and yes, the choke has a positive effect, eliminating all backfiring.
Will try to synchronize them to see if this does any good, otherwise I will open the carb again... I cleaned them thoroughly and checked the float ball heights but you never know what could have happened since...
Maybe something is clogging up the left carb...

Thanks for your coments and suggestions

Solved
I opened the left butterfly a little bit more
I also moved the slide needle down a notch (clip moved to central position - it was on 4th and now back on 3rd as per factory settings) , the engine was too rich

Evrything is now a lot smoother and the spark plugs dońt look mucky anymore, the bike is also idling perfectly

First time i hear of a bike having to be set leaner after adding pod filters, it seems that the set up was way too rich before I did... But then again, I just bought it and both diaphragms and gaskets were ripped so the previous owner probably tried to compensate for this.

Thanks for all the answers, suggestions, help