Motorcycle Repair: Backfiring, air fuel mixture, carburation

Question
Hello, i have a backfiring issue. The bike starts up, and Idle great. Bike also has plenty of power. But when the bike warms up, at idle, it backfires, a couple of pops every 2 seconds or so. When I accellerate there is no backfiring, and of course when I let off throttle is backfires. But the problem is when I hold  the throttle (cruising) at 2500rpm and higher, it backfires like crazy. The bike was on 93 octane, but I was told that this caused the problem, so I switched to 87. It made the problem worse, and now power is lagging at lower RPM. So now im going to go back to 93. The bike is completely stock. Ive tried adjusting the air/fuel mixture screws, but with no success. Not sure on how to fix this. Thanks!
Chris

Answer
Not many bikes need hi-test fuel, but it sounds like yours was laid up for a while.  The backfiring is either pre-ignition or carburation problems.  Since the gas in the US is so bad, I suspect a carb issue so clean the carburettor properly especially the two jet circuits and try it again.  Good luck,  Jan