I havent heard anything, I was thinking of something else, If the bike had been sitting with gas in the carbs, (over Winter??)
The inside of the carbs and/or needle valves could have gotten coated with varnish.
This coating could be choking off the gas supply. When sitting the carbs have the chance
to fill with gas. If varnished the gas supply may not be able to keep up with the gas being
used while running. The Bike is simply being starved of gas, that WILL cause sputtering,
I rethought the coils issue, usually if a coil goes bad it will shut down completely until cooled.
My Snow Blower did this exact thing this winter , it quit doing it when I pulled the bowel and float and cleaned it, it was always cold blooded so I adjusted the floats gas level
and now it runs perfectly, better than new..
In closing a lack of gas feed seems the right track. It makes the most sense, it gives the same results, and resolves itself when allowed to sit, Yes it is cooling but the carbs are filling up again. The supply just runs out, and the bike is just getting a trickle,
that explains the pops and missing, 3 guys hit it but there are several places this can be.
Plugged petcocks (but both would need to be plugged)
Plugged feed line,
varnished carbs..
It will take a complete fuel system disassemble, clean, Carb clean, Tank Clean, Kreme Koat to eliminate the issue..
