Just to clarify, I never leave the fuel tap on when the bike is not running. I used to mix my fuel (premium unleaded) at 40:1 after I rejetted the bike from the advice I received from this forum and the JustKDX website, but ended up going back to 32:1. I use Castrol TTS.
I gave it a run on the weekend (went away for 3 days to a 4WD/Motorbike park - awesome). The first day (with the same old fuel still in the tank) I still had trouble starting the bike and resorted to spraying the air filter with Aerostart. I was then able to start it with a couple of kicks. I rode for an hour or so with out any problems restarting it.
The next day it started 2nd kick. I topped up the couple of litres left in the tank with about 8 litres of fresh fuel, and rode the bike all day without any problems.
The third day, I again had to resort to using Aerostart to get the bike started.
I was hoping, by giving the bike a good blast after months of no use, that it would solve the problem.
I'll check it out further as per everyones advice.
Thanks