I've been back from my ride around Australia for two weeks now and it has been that long since I started the bike. I went out to fault find my broken Oxford heated grips and fiddle around for a few minutes with the ignition on before I thought it best to start the bike so I didn't drain the battery.
Engine turned over but wouldn't start. Checked voltage and it was reading 12.6 volts loaded, which meant it was marginal but would likely have read more than 12.8V disconnected which should have been enough. I kept cranking it over and after a minute or so it fired every now and again, but still would not start. Cranked it over off and on for another few minutes but still nothing.
It was time to change the spark plugs anyway, so I pulled off the air box in preparation and tried starting it again, to no avail. Changed the spark plugs (pain in the ass undoing/redoing the restraining bolts!), put it all back together and tried starting again. Nothing. The old plugs were wet with fuel from repeated cranking, but otherwise looked fine.
The fact that it had cranked for probably 5 minutes all up since I tried starting the bike, I figure the battery must have been OK after all. Nonetheless, it was starting to struggle turning the engine over, so I hooked up jumper leads to my son's car. More enthusiastic cranking, but again nothing.
In a last desperate attempt, I opened the throttle up full before hitting the started and she coughed into life, spluttering pulsing white smoke for the next five minutes while it warmed up. Took it for a test ride and rode it like I stole it and all was fine. Revved it in the garage and no more smoke. Bike now starts no problems.
What the heck would have caused this?