All sorted. It was the thermowax unit. Heres some instructions I found, hope it might help someone else in future, or just ask. Although I didnt follow these exactly, they did help a lot:
[/size]
[/size] should preferably remove the tank but you can instead just chock it up by placing a piece of 2 x 2 timber on top of the frame and under the rear lip.This has the advantage over propping it up of giving better access under the tank and you'll be able to run the engine later.The airbox needs to be removed but you can leave the velocity stacks sat in the airbox base just slacken the 6 bolts right off.Disconnect the 2 coolant hoses , there'll be almost no loss of fluid. I'd suggest at this point that before you remove the thermowax unit that you check the plunger for rust etc or worse case wax.If it looks ok spray some WD40 on it and work the plunger with your fingers. It should move freely apart from the spring tension.Any signs of wax and it'll need replacing.Reconnect the coolant hoses and airbox and start the engine.The plunger should not move till about 75 - 80*C when it should then extend fully pushing the tang onto the tickover adjustment screw thus reducing the rpm's to tickover level.Rev it, get it nice and hot, let the fans kick-in and observe the rpm's. If they rise unexpectedly check to see if the plunger is still pressed against the tickover screw.If it isn't, the unit will need to be removed and maybe replaced, but I'd try copious amounts of WD40 first.To remove the unit undo the 2 screws, disconnect the spring, take the tickover adjustment cable out of it's holder and pull clear.With it out of the bike split the unit and clean and oil the plunger thoroughly before retrying it. Hopefully though, it can be sorted in situ.Also, while you're in there give the throttle cable mechanisms a good oiling
