Ok, I've got a wierd issue. 1987 with 74,000 miles and I've owned since new.
I think this is carb related but see what you think.
Bike is hard to start, even just after it has been ridden 20 miles. Sometimes get a backfire when trying to start it.
When it is running, it idles great, runs great, plenty of top end.
I had previously had a backfire issue and hard starting so I pulled the carbs, installed new orings, needles, float bowl orings, pilot orings/washers, and adjusted the float levels and double checked with hose. Bike ran fine for a few months after that and now it is acting up again.
Fresh fuel, full tank, valves have a few thousand miles before adjustment needed, installed new pickup coils last year. Tried a different ICU box I had as a spare. New Yuasu battery 2 years ago. Stic coils 2 years ago.
Yesterday for the heck of it I drained all the float bowls. The bike was cold, hadn't been ridden for 2-3 weeks. I put the petcock on prime for 10 seconds, then choked it and it started up pretty quick and I was surprised. Rode the bike 20 miles. Parked in driveway. front end was up a few inches higher than rear because of driveway slope. The bike had been shut off for a few minutes then I tried to start and it was hard to start again but no backfire.