No these are all the things I did before asking for advise. Anyway I have worked out the problem. It was the manifold. Even tho it looked the same as a standard one the end where the carb attaches was about 1.5mm shorter than it should be. Because of this although the carb was going on as far it can go it was not making a seal with the rubber ring in the carb and air was getting in. I had another manifold and ive swapped it over and it is now running fine. If I didn't have the other manifold lying around I doubt I would have ever figured this out either.
Thanks for your help guys.
