cough splutter burp

I got to look into the starting and idling problems over the weekend, I have a good spark and I know the fuel is getting there as the plug is fouling, the idle is OK but just dies after a minute or two, unless I feather the throttle, I thought Id throw in the old idle jet from the smaller carb I had on it originally, It did idle better and longer but still died. I went for a short ride up the road and she began to stutter and died, I got a few bursts of life trying to get going again, but I eventually rolled/pushed it back the 500m back home, it was for this reason I decided to go up the hill and not down it.
I got back to the shed and decided to give her a birthday since I was most likely going to pull the carb out anyway, I changed the gear oil, I checked and cleaned the plug, it was a little browner than it was after the plug chop, but I did notice that the little nipple on the end was loose? a possible cause? I re-torqued the cylinder head nuts too, which did seem a little loose to me, there was a small leak at the base of the head, another likely cause of the starting problem, low compression.
I disconnected the carb and pulled it down, I found no obvious blockages, there was some crap below the filter screen though, I blew out all the jets and holes as best I could and put it all back together. I did the same run up the hill and it ran a little better, still feels like there is a fuel delivery issue, just seemed to miss every now and then and the acceleration was lacking towards the top of the range 80kmph and up, getting to eighty wasn't a problem, she pulled hard through the gears. I got back and the first thing I did was pull the plug, it was clean as a whistle, it's a new plug, this worries me a bit that I might be a bit lean It still wont idle for long so I set about adjusting the throttle cable nipple along about 3-4mm to open the slide just a small bit at idle and give me some room for idle adjustment, this seemed to work and the idle problem seemed done with. I ran out of daylight so decided to call it a day until the morning.
I checked the weather and decided to ride the Sprint to work, it started after four kicks, OK since it was a cold frosty morning, idle was a tad fast but I would adjust that when the engine was warm. I rode out and down toward town, same running issues as yesterday, so I turned around in case she died and I didn't feel like pushing it home up the hill first thing Monday morning, It didn't stop but I had to keep the revs up and the clutch grabbing to turn around, I lifted the front wheel twice turning around, once home I shut it off and will look at it when I get home, I then proceeded to start the GT200 take off and perform a rear wheel spin 180 degrees and layed it down on the cold wet soft ground.....no harm done but would've looked pretty funny, note to self. Don't give it too much on the wet grass until you get going....