I don't believe it!

It's been a damp misty day today, although my contact up north says it cleared away late morning up there. Down south it was late afternoon before things dried up, so we decided to go for a little evening ride. I was going to give my NA a run as I've only been out on it a couple of times this year. Gill was going to give the 125 a test run as we've had a few problems with the fuel tank -  more on that later. I had to jump start the NA, which was not unexpected given it's lack of use. While that was ticking over, I started up the 125, which took quite a while - not normal. Once I got it going, it wouldn't tick over, but I handed it over to Gill saying it would be ok once it warmed up (fingers crossed!) Well, it wouldn't pull up the ever so slight hill away from our house, so I had to admit something was wrong & the ride was aborted. Back on the drive, I felt the pipes & the right hand exhaust was cold. Now the first rule of diagnosis is 'what's changed?' If something was working & you've changed or messed with some part of it, that's the first suspect - so fuel right? I'd drained & removed the tank and supply pipes, so surely that would be where the problem lay. I opened the drain screw on the right hand carb & petrol came out, so that was that theory knocked on the head. Spark plugs were only about 18 months & 800 mile old & coils & HT leads were in place & undamaged. I changed the spark plug anyway & it fired up straight way on both cylinders and ticked over at a steady 1,200 rpm Plugs are NGK, bought from a bike shop and have been working fine, so it's a bit of a concern if  even these are now of questionable quality now
Anyway, at least we were able to get back to our little ride, and I guess we're luckier than the guy that owns the boat in the middle distance just in front of my right hand mirror