Hi there can someone give me some advice.
When I got back from my Sunday ride I noticed that when I shut the throttle off, it goes over a stop position. i.e to rev the engine I need to turn it about a third of a turn back until it clicks over "something" before revs are raised. Do you think that it the throtlle tube that is worn and if so any ideas on availability and cost.

Yeah, does sound like your throttle tube may be broken. You should be able to check it by removing the back of the pulley housing. You can get a replacement throttle tube from Graeme France fairly cheap.

I thought it was the best place to start.
Is it as easy to replace as this example on you tube.
http://www.youtube.com/watch?v=cHvkYDVR3Lo" onclick="window.open(this.href);return false;

I know he's doing it on a different bike, but is as straight forward.
I'm quite handy with a set of spanners and prepared to have a go myself.

regards

Yeah it's very easy - the hardest bit will probably be getting the grip off the throttle tube if you want to reuse it.

Having said that, you may need to take the tank and airbox off if you can't get enough cable slack at the top end.

Check that the throttle tube is actually broken before diving in with the above - undo the two screws on the back of the pulley housing (rider side) to reveal the pulley part of the throttle tube, and rotate the tube to check it.

Quick mechanics tip - to remove and refit handlebar grips - use an air line with a pistol type blow gun to simply expand the grip over the handlebar - 5 second job ....

OK I know not everyone has a compressor - but even the smallest cheapest models can do this.

Thank you both, parts are ordered and hopefully I'll fit it on the weekend, Ill let you know how it goes.
Regards

Just to update, removed the throttle grip okay, a hot day helped.
Released the throttle cable housing after soaking screw threads with WD40 and leaving for half hour. Only to find that although the throttle tube was cracked and split, the throttle close cable was also broken.
So removed the fuel tank then the airbox and removed the cable.

I'm going to order two new cables as I don't want the other one breaking next week.

Q: Do I need to remove the carburettor in order to fit the new cables.

No, you should be able to do it with the carbs in place. You may want to disconnect the choke cable if it's in the way. Probably won't be though.

be prepared for frustration, not a pro by any means but i did this once and getting the lugs in is a pain in the a*s

All fitted and working, like you said easy to fit without removing the carbs.
Unfortunately flicked off the kill switch without noticing and then couldn't work out why it won't start!!!!!!!!
I must say how good Graeme France service delivery is. Ordered two sets of parts and both arrived the following day.
My friends are amazed how easy it was to get the parts, even more amazed I fitted them (but I'm not letting on about the kill switch.)
Thanks everyone for your help.

It's the weekend, the bikes back up and running
Time to play, happy days.