Ok so recent update:
Lots done to find the problem. Carbs rebuilt. All new gaskets, jets etc.
Compression check: Ok
Fuel tap rebuilt.
Valve check: Problem with front cylinder.
So far this is what was wrong. Opened the cylinder cover and cam cover. Took off the tensioners and removed cams. ( making sure it was tdc and marks aligned. (Turned engine by hand)
2 of the cam guides that sit on the lash adjusters had fallen off. It must have happened when i put the cams on the first time without me realising. So spockster you were right about the valves.
I have yet to fire it up as it was late last night when i finished putting it back together. The whole procedure was done with the engine on the bike. Took about an hour in total. I will post the outcome later.