Foccers
Left the old girl at work while I went on holiday, although she was covered the spot was quite exposed and the black cover wouldn't have helped with the temperatures we've been having. I foolishly did nothing to prepare the bike to be laid up for a month other than putting the cover on.
Turned the key and the dash sprang to life, let the fuel pump fill the carbs, this took a few seconds so I knew the contents had evaporated. It was already 20 deg out so I gave no choke. Turned the key and the starter motor did it's thing but there was no fire. Did this for a good 10 seconds and also gave half choke. Nothing. Turned off the lights to give the starter full current, tried again. It did eventually fire with half choke but it was running very weakly, about 300rpm, tried giving a little gas and it cut off. Started her again and it only fired after about 5 seconds of starter motor, again at about 300rpm. Tried gently applying more choke and it cut again. After a few mins of this eventually it started to warm up and ran like the good bike I know it is. The battery was nearly flat so this was quite lucky.
My thinking:
Probably just a fuel supply problem, too much air in the carbs which took a while to push through, I use Marvel Mystery Oil and she was only still for a month so I don't think dodgy fuel could be the cause.
Possible other causes:
Weak spark
Exhaust is original, the downpipes are starting to corrode on the outside, inside could be worse causing back pressure. (50 000km on the clock)
Cylinder 3 doesn't warm up as quickly as the others, carbs were recently balanced so this is something I decided to just live with.
Maybe ignition
Anyone else care to weigh in