OK this has turned into a grand mystery. call me stooopid, but see if you can figure this one out. its gotta be simple I had a fine-running BRP, except for "popcorn" on hard decel. Rode it all over southern new mexico, having a blast. would start on the first kick Cold or Hot. Lovely.... So I get back home and one day decide to bump up the Pilot jet to cure the backpop. Pulled the carb, flipped it over and unscrewed the 62 pilot, put in a 68 pilot. While doing this the float assembly fell out. i put it back in. Reassembled the bike Tried for a couple of days to get it to start. It will backfire in the can but not start no matter the mix-screw setting. Put the 62 back in just to see. Tried for a week everything I could think of to get it to start. Finally in utter frustration took to the honda shop... the one here is the best I've ever seen. Best Service Manager I've ever seen in Motorcycleland. Left it with them A week went by with no calls. I went down there today to see what's up. Found them stumped. Completely baffled. They have no clue why it won't start. Swapped out spark plugs, checked valves, checked compression, consulted the stars, grabbed voodoo doll, kicked it a million times. Same thing.... huge, flamethrowing backfires so loud it wakes the dead, but will not start. ok, so something simple changed. Bike started and ran super. Especially easy to start. Now it won't start. Has good spark, has good specs, SEEMS to have fuel if its backfiring that impressively. What happened? What causes a spot-on PERFECT backfire... just one per kick [well its usually about the third or fourth kick that lights her off...] ????? Did something ELSE fall out of that carburetor? I have a symptom-theory that the fuel is not emulsifying correctly. its sucking a lotta fuel in, pushing the vapors into the can. the fuel residue in the cylinder "flames" without firing, and when the exhaust valve opens it lights off the buildup of vapors in the exhaust pipe. But why is the carb not carbing ???