problem sorted! after alot of faffing around with jets, exhausts, needle heights i found the problem. when changing the jet i noticed the emulsion tube where the jet screws in could move up and down. but theres no grub screw just a pressed in brass pin as a retainer, so gave that a few firm taps and it runs sweet now! fmf fatty and power core 2 next. seems to run sweet and fuel rite on a 240 jet, and have no issues with using the standard head on the 240 kit. it definately benifitted from a k and n. im thinking it will be pretty quick with a race pipe on now, roll on the summer! cheers for all your feedback fellas. 
