It mainly backfires thru the carb, but if I get on it hard, it does both.

tried dist cap, nothing
fuel filter, nothing
fuel flow from tank, I can fill a 2 pound coffee can in about 20 sec.
new fuel pump, nothing
took out jets, metering rods etc, clean
exhaust flowed fine when I took motor out, unless theres a mouse in there, but I wouldn't think that would change with time or temp.
I think I have another coil, I can stick it in and try it.
My fuel line is all hard plumbed, except from frame to pump, which is only a year old, so I don't see any kind of a fuel line collapse issue.
Thank you for your input. I'll keep you posted.