Yeah this

 

Ok. maybe the old fuel affects on caughing, but does it affect on backfiring thru carb?

 

YES!...........fuel not burning creates LEAN mixture.

 

Ok sir. I`ll check that out. I will clean tank, empty carb. Then fill up tank and ride

 

And if that does not work you may need to clean carbs to clear plugged passages/jets..........good luck.

 

 

How many turns out is "properly set?" Mine's set at about 2.5 turns out, no carb pops.

When was the last time you changed the manifold seals at the heads?

If it sat for a year, very likely some passages or jets have some residue built up, need to clean all those "boogers" out.

Have you tried Seafoam gas treatment? It worked well on my 1991 before I did a complete carb rebuild and replaced manifold seals.

John

 

These guys have what you need.

https://cv-performance.com/carburetor-parts/

 

I have changed my manifold seals, They are brand new.

 

Coughing through the carb is a sign of the pilot jetted too lean.

Here is a good vid about jetting.and tuning. Shows symptoms of main and intermediate jets too lean and too rich.

It could also be your idle mixture is too lean.