Thanks guys, the guy I bought the bike off was using it till I bought it (4months
ago) so hasn't been sitting around.
Your right , I don't think my testers were sitting properly in the plug holes because when I brought them out they was marked along the bottom edge.
I had time to whip of the rocker cover and check valves clearances, and there all pretty much within spec (1 or 2 are 1thou tight or so)
I have a lot of time to think about this on my commute to and from work haha , so I'm starting to think it's a jet hopefully ( I should've really checked when I was doing the float levels the other day)
That all I can think of, without going much further into pistons and ring which id rather not haha
I might try get some pictures / videos to show what I'm doing...
Unfortunately my dad managed to snap the 5 way carb fuel joining pipe when we had them out so I've ordered a new one from Japan so until that comes I don't want to pull the carbs and start playing with them because I've managed to keep it going with some tube an T peices and it's not leaking yet haha